,,! ,,int]national ,,sci5tific ,,s]ies ,,volume ,,lv ,,! ,,int]national ,,sci5tific ,,s]ies ,,e>?quakes ,,& ,,o!r ,,e>? ,,movem5ts ,,by ,,john ,,milne ,,pr(essor ,,( ,,m9+ ,,& ,,geology ,,9 ,,! ,,imp]ial ,,college ,,( ,,eng9e]+1 ,,tokio1 ,,japan ,,) ,,?irty-,,eight ,,figures ,,new ,,york ,d4 ,,appleton ,,& ,,company #a1 #c1 ,,& #e ,,bond ,,/reet #ahhf ,,preface4 ,9 ! foll[+ pages x has be5 my object to give a sy/ematic acc\nt ( v>i\s ,e>? ,movem5ts4 ,^! comprise ,e>?quakes1 or ! sudd5 viol5t movem5ts ( ! gr\nd2 ,e>? ,tremors1 or m9ute movem5ts :i* escape our att5tion by ! smallness ( _! amplitude2 ,e>? ,pulsations1 or movem5ts :i* are ov]look$ on acc\nt ( ! l5g? ( _! p]iod2 & la/ly1 ,e>? ,oscillations1 or movem5ts ( long p]iod & l>ge amplitude :i* attract s mu* att5tion f _! geological importance4 ,x is difficult to sep>ate ^! ,e>? ,movem5ts f ea* o!r1 because !y are ph5om5a :i* only diff] 9 degree1 & :i* are intimately associat$ 9 _! occurr5ce & 9 _! orig94 ,because ,e>?quakes are ph5om5a :i* h attract$ a univ]sal att5tion s9ce ! e>lie/ times1 & ab\t !m s _m obs]vations h be5 made1 !y are treat$ ( at consid]able l5g?4 ,z v mu* ( :at might be said ab\t ! o!r ,e>? ,movem5ts is common to :at is said ab\t ,e>?quakes1 x has be5 possible to make ! description ( ^! ph5om5a comp>atively %ort4 ,! s*eme :i* has be5 adopt$ w be und]/ood f ! foll[+ table3-- ,i4 ,,e>?quakes4 #a4 ,introduction4 #b4 ,seismometry4 7a7 ,!oretically4 #c4 ,e>?quake ,motion4 7b7 ,z d$uc$ f exp]im5ts4 7c7 ,z d$uc$ f actual ,e>?quakes4 #d4 ,e>?quake ,effects4 7a7 ,on l&4 7b7 ,9 ! ocean4 #e4 ,det]m9ation ( ,e>?quake orig9s4 7a7 ,9 space4 #f4 ,di/ribution ( ,e>?quakes4 7b7 ,9 "t 7geological "t1 hi/orical "t1 annual1 seasonal1 diurnal1 c47 #g4 ,cause ( ,e>?quakes4 #h4 ,e>?quake pr$iction & w>n+4 ,,ii4 ,,e>? ,,tremors4 ,,iii4 ,,e>? ,,pulsations4 ,,iv4 ,,e>? ,,oscillations4 ,9 "s in/ances ! gr\p+ ( ph5om5a accord+ to ! above s*eme may be f\nd inaccurate1 z1 = example1 9 ! *apt]s ref]r+ to ! effects & causes ( ,e>?quakes4 ,?is arises f ! fact t ! relation%ip betwe5 ,e>?quakes & o!r ,e>? ph5om5a are n well und]/ood4 ,?us ! sudd5 elevation ( a coa/ l9e & an accompany+ e>?quake may be relat$1 ei!r z effect & cause1 or vice v]s1 or !y may bo? be ! effect ( a ?ird ph5om5on4 ,mu* ( :at is said respect+ ,e>?quake motion w %[ h[ little accurate k we h ab\t ^! di/urbances4 ,_h ,i be5 writ+ 9 ,engl&1 &1 !re=e1 be5 9 a position to make ref]5ces to libr>ies & p]sons :o are au?orities on subjects connect$ ) ,seismology1 ! foll[+ pages might h be5 made m complete1 & inaccuracies avoid$4 ,a l>ge proportion ( ! mat]ial embodi$ 9 ! foll[+ pages is f\nd$ on exp]im5ts & obs]vations made dur+ an eight ye>s' resid5ce 9 ,japan1 :]e ,i h _h ! opportunity ( record+ an e>?quake e week4 ,! writ] to :om ,i am *iefly indebt$ is ,mr4 ,rob]t ,mallet4 ,n be+ 9 a position to ref] to orig9al memoirs1 ,i h drawn _m illu/rations f ! works ( ,pr(essor ,k>l ,fu*s & ,m4 ,s4 di ,rossi4 ,^!1 & o!r writ]s to :om ref]5ce has be5 made1 are giv5 9 an app5dix4 ,= see+ ^! pages ?r\gh ! press1 my ?anks are due to ,mr4 ,?omas ,gray1 :o1 :5 resid+ 9 ,japan1 did s mu* = ! advancem5t ( obs]vational ,seismology4 ,= advice & assi/ance 9 devis+ exp]im5ts1 ,i t5d] my ?anks to my colleagues1 ,pr(essor ,t4 ,alex&]1 ,mr4 ,t4 ,fujioka1 & to my late colleague4 ,pr(essor ,john ,p]ry4 ,= assi/ance 9 ! actual obs]vation ( ,e>?quakes1 ,i h to ?ank my fri5ds 9 v>i\s p>ts ( ,japan1 especially ,mr4 ,j4 ,bissett & ,mr4 ,t4 ,talbot1 ( ,yokohama4 ,= assi/ance 9 obta9+ in=mation f ,italian s\rces ,i h to ?ank ,dr4 ,f4 ,du ,bois1 f ,g]man s\rces ,pr(essor ,c4 ,netto1 & f ,japanese s\rces ,mr4 ,b4 ,h4 ,*amb]la94 ,= help 9 c>ry+ out exp]im5ts1 ,i am indebt$ to ! lib]ality ( ! ,briti% ,association1 ! ,geological ,society ( ,london1 ! ,meteorological & ,telegraph dep>tm5ts ( ,japan1 & to ! (fic]s ( my own in/itution1 ! ,imp]ial ,college ( ,eng9e]+4 ,&1 la/ly1 ,i (f] my s9c]e ?anks to ^? g5tlem5 :o h tak5 "p 9 ! e/abli%m5t & work+ ( ! ,seismological ,society ( ,japan1 & to my publi%]s1 ^: lib]ality has enabl$ me to place ! lab\rs ( resid5ts 9 ! ,f> ,ea/ be=e ! ,european public4 ,,john ,,milne4 ,,tokio1 ,,japan2 ,june #cj1 #ahhc ,,cont5ts4 ,,*apt] ,i4 ,,introduction4 ,,page ,relation%ip ( man to nature--,! aspect ( a c\ntry is dep5d5t on geological ph5om5a--,e>?quakes an important geological ph5om5on--,relation%ip ( seismology to ! sci5ces & arts--,e>? movem5ts o!r ?an e>?quakes--,seismological lit]ature--7,writ+s ( ,p]rey1 ,mallet1 ,ea/]n writ+s1 ! ,philosophical ,transactions ( ! ,royal ,society1 ! #8,g5tleman's ,magaz9e1' ! ,bible1 ,h]odotus1 ,pl9y1 ,hopk9s1 ,von ,h(f1 ,humboldt1 ,s*midt1 ,seeba*1 ,lasaulx1 ,fu*s1 ,palmi]i1 ,b]telli1 ,seismological ,society ( ,japan7--,seismological t]m9ology #a ,,*apt] ,,ii4 ,,seismometry4 ,nature ( e>?quake vibrations--,_m in/rum5ts call$ seismomet]s only seismoscopes--,ea/]n seismoscopes1 columns1 projection seismomet]s--,vessels fill$ ) liquid--,palmi]i's m]cury tubes--,! %ip seismoscope--,! cacciatore--,p5dulum in/rum5ts ( ,kreil1 ,wagn]1 ,ew+1 & ,gray--,bracket seismographs--,we/'s p>allel motion in/rum5t--,gray's conical p5dulums1 roll+ sph]es1 & cyl9d]s--,v]beck's ball & plate seismograph--,! pr9ciple ( ,p]ry & ,ayrton--,v]tical motion in/rum5ts--,record receiv]--,"t-record+ app>atus--,! ,gray & ,milne seismograph #ab ,,*apt] ,,iii4 ,,e>?quake ,,motion ,,discuss$ ,,!oretically4 ,ideas ( ! anci5ts 7! views ( ,travag9i1 ,hooke1 ,woodw>d1 ,/ukeley1 ,mit*ell1 ,"y1 ,mallet7--,nature ( ela/ic waves & vibrations--,possible causes ( di/urbance 9 ! e>?'s cru/--,! "t ( vibration ( an e>? p>ticle--,velocity & accel]ation ( a p>ticle--,propagation ( a di/urbance z det]m9$ by exp]im5ts ^u ! ela/ic moduli ( rocks--,! int5sity ( an e>?quake--,area ( greate/ ov]turn+ mom5t--,e>?quake waves--,reflexion1 refraction1 & int]f]5ce ( waves--,radiation ( a di/urbance #da ,,*apt] ,,iv4 ,,e>?quake ,,motion ,,z ,,d$uc$ ,,f ,,exp]im5t4 ,exp]im5ts ) fall+ weights--,exp]im5ts ) explosives--,results obta9$ f exp]im5ts--,relative motion ( two adjac5t po9ts--,! effect ( hills & excavations ^u ! propagation ( vibrations--,! int5sity ( artificial di/urbances--,velocity ) :i* e>? vibrations are propagat$--,exp]im5ts ( ,mallet--,exp]im5ts ( ,abbot--,exp]im5ts 9 ,japan--,mallet's results--,abbot's results--,results obta9$ 9 ,japan #eg ,,*apt] ,v4 ,,e>?quake ,,motion ,,z ,,d$uc$ ,,f ,,obs]vation ,,on ,,e>?quakes4 ,result ( feel+s--,! direction ( motion--,in/rum5ts z indicators ( direction--,duration ( an e>?quake--,p]iod ( vibration--,! amplitude ( e>? movem5ts--,side ( greate/ motion--,int5sity ( e>?quakes--,velocity & accel]ation ( an e>? p>ticle--,absolute int5sity ( an e>?quake--,radiation ( an e>?quake--,velocity ( propagation #fg ,,*apt] ,,vi4 ,,effects ,,produc$ ,,by ,,e>?quakes ,,^u ,,build+s4 ,! de/ruction ( build+s is n irregul>--,cracks 9 build+s--,build+s 9 ,tokio--,relation ( de/ruction to e>?quake motion--,measurem5t ( relative motion ( p>ts ( a build+ %ak5 by an e>?quake--,prev5tion ( cracks--,direction ( cracks--,! pit* ( ro(s--,relative position ( op5+s 9 a wall--,! la/ h\se 9 a r[--,! sw+ ( build+s--,pr9ciple ( relative vibrational p]iods #if ,,*apt] ,,vii4 ,,effects ,,produc$ ,,^u ,,build+s 7cont9u$74 ,types ( build+s us$ 9 e>?quake c\ntries--,9 ,japan1 9 ,italy1 9 ,s\? ,am]ica1 9 ,c>accas--,typical h\ses = e>?quake c\ntries--,de/ruction due to ! nature ( und]ly+ rocks--,! sw+ ( m\nta9s--,want ( support on ! face ( hills--,e>?quake %ad[s--,de/ruction due to ! int]f]5ce ( waves--,e>?quake bridges--,examples ( e>?quake effects--,protection ( build+s--,g5]al conclusions #abb ,,*apt] ,,viii4 ,,effects ,,( ,,e>?quakes ,,on ,,l&4 #a4 ,cracks & fissures--,mat]ials dis*>g$ f fissures--,explanation ( fissure ph5om5a4 #b4 ,di/urbances 9 lakes1 riv]s1 spr+s1 wells1 fum>oles1 c4--,explanation ( ^! latt] ph5om5a4 #c4 ,p]man5t displacem5t ( gr\nd--,on coa/ l9es--,level tracts--,among m\nta9s--,explanation ( ^! movem5ts #adf ,,*apt] ,,ix4 ,,di/urbances ,,9 ,,! ,,ocean4 ,sea vibrations--,cause ( vibratory bl[s--,sea waves3 prec$+ e>?quakes2 succe$+ e>?quakes--,magnitude ( waves--,waves z record$ 9 c\ntries di/ant f ! orig9--,records on tide gauges--,waves )\t e>?quakes--,cause ( waves--,ph5om5a difficult ( explanation--,velocity ( propagation--,dep? ( ! ocean--,examples ( calculations--,comp>ison ( velocities ( e>?quake waves ) velocities :i* ought to exi/ f ! kn[n dep? ( ! ocean #afc ,,*apt] ,x4 ,,det]m9ation ,,( ,,e>?quake ,,orig9s4 ,approximate det]m9ation ( an orig9--,e>?quake-hunt+ 9 ,japan--,det]m9ations by direction ( motion--,direction indicat$ by de/ruction ( build+s--,direction det]m9$ by rotation--,cause ( rotation--,! use ( "t obs]vations--,errors 9 su* obs]vations--,orig9 det]m9$ by ! me?od ( /raight l9es--,! me?od ( circles1 ! me?od ( hyp]bolas1 ! me?od ( co-ord9ates--,haughton's me?od--,diff]5ce 9 "t betwe5 s\nd1 e>?1 & wat] waves--,me?od ( ,seeba* #ahg ,,*apt] ,,xi4 ,,! ,,dep? ,,( ,,an ,,e>?quake ,,c5trum4 ,! dep? ( an e>?quake c5trum--,greate/ possible dep? ( an e>?quake--,=m ( ! focal cavity #bac ,,*apt] ,,xii4 ,,di/ribution ,,( ,,e>?quakes ,,9 ,,space ,,& ,,"t4 ,g5]al di/ribution ( e>?quakes--,occurr5ce along l9es--,examples ( di/ribution--,italian e>?quake ( #ahgc--;,9 ,tokio--,ext5sion ( e>?quake b\nd>ies--,seismic en]gy 9 relation to geological "t2 to hi/orical "t--,relative frequ5cy ( e>?quakes--,syn*ronism ( e>?quakes--,second>y e>?quakes #bbf ,,*apt] ,,xiii4 ,,di/ribution ,,( ,,e>?quakes ,,9 ,,"t 7cont9u$7 #bcd ,,*apt] ,,xiv4 ,,di/ribution ,,( ,,e>?quakes ,,9 ,,"t 7cont9u$74 ,! occurr5ce ( e>?quakes 9 relation to ! position ( ! heav5ly bodies--,e>?quakes & ! moon--,e>?quakes & ! sun2 & ! seasons2 ! mon?s--,planets & meteors--,h\rs at :i* e>?quakes are frequ5t--,e>?quakes & sun spots--,e>?quakes & ! aurora #bej ,,*apt] ,,xv4 ,,b>ometrical ,,fluctuations ,,& ,,e>?quakes--,,fluctuations ,,9 ,,temp]ature ,,& ,,e>?quakes #bff ,,*apt] ,,xvi4 ,,relation ,,( ,,seismic ,,to ,,volcanic ,,ph5om5a4 ,want ( syn*ronism betwe5 e>?quakes & volcanic eruptions--,syn*ronism betwe5 e>?quakes & volcanic eruptions--,conclusion #bgj ,,*apt] ,,xvii4 ,,! ,,cause ,,( ,,e>?quakes4 ,mod]n views respect+ ! cause ( e>?quakes--,e>?quakes due to fault+--,to explosions ( /eam--,to volcanic evisc]ation--,to *emical degradation--,attractive influ5ce ( ! heav5ly bodies--,! effect ( oceanic tides--,v>iation 9 atmosph]ic pressure--,fluctuation 9 temp]ature--,w9ds & e>?quakes--,ra9 & e>?quakes--,conclusion #bgg ,,*apt] ,,xviii4 ,,pr$iction ,,( ,,e>?quakes4 ,g5]al nature ( pr$ictions--,pr$iction by ! obs]vation ( unusual ph5om5a 7,alt]ation 9 ! appe>ance & ta/e ( spr+s2 und]gr\nd noises2 prelim9>y tremors2 ,e>?quake prophets--w>n+s furni%$ by animals1 c47--,e>?quake w>n+ #big ,,*apt] ,,xix4 ,,e>? ,,tremors4 ,artificially produc$ tremors--,obs]vations ( ,kat]1 ,d5man1 ,airy1 ,palm]1 ,paul--,natural tremors--,obs]vations ( ,zlln]1 ,m4 d',abbadie1 ,g4 ,h4 & ,h4 ,d>w9--,exp]im5ts 9 ,japan--,) seismoscopes1 microphones1 p5dulums--,"w 9 ,italy--,b]telli1 ,c\nt ,malvasia1 ,m4 ,s4 di ,rossi--,in/rum5ts employ$ 9 ,italy--,tromomet]s1 microseismographs1 microphones--,results obta9$ 9 ,italy--,9 ,japan--,cause ( microseismic motion #cjf ,,*apt] ,,xx4 ,,e>? ,,pulsations4 ,def9ition ( an e>? pulsation--,indications ( p5dulums--,indications ( levels--,o!r ph5om5a indicat+ ! exi/5ce ( e>? pulsations--,di/urbances 9 lakes & oceans--,ph5om5a resultant on e>? pulsations--,cause ( e>? pulsations #cbf ,,*apt] ,,xxi4 ,,e>? ,,oscillations4 ,evid5ces ( oscillation--,examples ( oscillation--,temple ( ,jupit] ,s]apis--,obs]vations ( ,d>w9--,causes ( oscillation #cdd ,,app5dix #cdi ,,index #cei ,,e>?quakes4 ,,*apt] ,i4 ,,introduction4 ,relation%ip ( man to nature--,! aspect ( a c\ntry is dep5d5t on geological ph5om5a--,e>?quakes an important geological ph5om5on--,relation%ip ( seismology to ! sci5ces & arts--,e>? movem5ts o!r ?an e>?quakes--,seismological lit]ature--7,writ+s ( ,p]rey1 ,mallet1 ,ea/]n writ+s1 ! ,philosophical ,transactions ( ! ,royal ,society1 ! #8,g5tleman's ,magaz9e1' ! ,bible1 ,h]odotus1 ,pl9y1 ,hopk9s1 ,von ,h(f1 ,humboldt1 ,s*midt1 ,seeba*1 ,lasaulx1 ,fu*s1 ,palmi]i1 ,b]telli1 ,seismological ,society ( ,japan7--,seismological t]m9ology4 ,9 bygone sup]/iti\s times lightn+ & ?und] 7 reg>d$ z sup]natural visitations4 ,b z ^! ph5om5a became bett] und]/ood1 & m5 le>n$ h[ to avoid _! de/ructive p[]1 ! sup]/ition 0 gradually dispell$4 ,?us x is ) ,e>?quakes3 ! m cle>ly !y are und]/ood1 ! m confid5t 9 ! univ]sality ( law w man become1 & ! m w 8 m5tal condition be advanc$4 ,9 8 #8,hi/ory ( ,civilisation 9 ,engl&1' ,buckle has laid consid]able /ress ^u ! mann] 9 :i* e>?quakes1 volcanoes1 & o!r ( ! m t]rible =ms 9 :i* ! work+s ( nature reveal !mselves to u1 h ex]t$ an influ5ce ^u ! imag9ation & und]/&+2 & j z a sudd5 fright may affect ! n]ves ( a *ild = ! rema9d] ( its life1 we h 9 ! annals ( seismology records :i* indicate t e>?quakes h n be5 )\t a s]i\s influ5ce ^u ! m5tal condition ( :ole communities4 ,to a geologi/ !re are p]haps no ph5om5a 9 nature m int]e/+ ?an e>?quakes1 ! /udy ( :i* is call$ ,seismology4 ,com+1 z %ocks (t5 w1 f a region ( volcanoes1 ! /udy ( ^! di/urbances may enable u to und]/& some?+ ab\t ! nature & work+ ( a volcano4 ,z an e>?quake wave travels along f /rata to /rata1 if we /udy its reflections & *ang+ velocity 9 transit1 we may (t5 be l$ to ! discov]y ( c]ta9 rocky /ructures buri$ deep b5ea? our view1 ab\t :i*1 )\t ! help ( su* waves1 x w\ld be hopeless ev] to atta9 any k4 ,by /udy+ ! propagation ( e>?quake waves ! physici/ is enabl$ to confirm 8 speculations respect+ ! transmission ( di/urbances 9 ela/ic m$ia4 ,= ! physici/ e>?quakes are gigantic exp]im5ts :i* tell him ! ela/ic moduli ( rocks z !y exi/ 9 nature1 & :5 prop]ly int]pret$ may lead him to ! prop] compreh5sion ( _m ill-und]/ood ph5om5a4 ,x is n impossible t seismological inve/igation may tea* u some?+ ab\t ! e>?'s magnetism1 & ! connection betwe5 e>?quakes & ! #8e>? curr5ts' :i* appe> 9 our telegraph wires4 ,^! & num]\s o!r k9dr$ problems fall )9 ! doma9 ( ! physici/4 ,x is ( int]e/ to ! meteorologi/ to "k ! connections :i* probably exi/ betwe5 e>?quakes & ! fluctuations ( ! b>omet]1 ! *anges ( ! !rmomet]1 ! quantity ( ra9fall1 & l ph5om5a to :i* he devotes 8 att5tion4 ,next we may turn to ! m practical aims ( seismology & ask ourselves :at are ! effects ( e>?quakes ^u build+s1 & h[1 9 e>?quake-%ak5 c\ntries1 ! build+s are to be made to )/& !m4 ,"h we are face to face ) problems :i* dem& ! att5tion ( eng9e]s & build]s4 ,to atta9 :at we desire1 obs]vation1 common s5se1 & subtle reason+ mu/ be br\ght to be> ^u ?is subject4 ,9 ! inve/igation ( ! pr9ciple on :i* e>?quake in/rum5ts make _! records1 9 ! analysis ( ! results !y give1 9 problems connect$ ) a/ronomy1 ) physics1 & ) con/ruction1 seismology (f]s to ! ma!matician new fields = inve/igation4 ,a /udy ( ! effects :i* e>?quakes produce on ! l[] animals w n fail to int]e/ ! /ud5t ( natural hi/ory4 ,a /udy l seismology1 :i* leads u to a m complete k ( e>?-heat & its work+s1 is to be reg>d$ z "o ( ! corn]-/ones ( geology4 ,! sci5ce ( seismology invites ! co-op]ation ( work]s & ?9k]s 9 almo/ e dep>tm5t ( natural sci5ce4 ,we h already ref]r$ to ! influ5ce ex]t$ by e>?quakes ov] ! human m9d4 ,h[ to pr$ict e>?quakes1 & h[ to escape f _! dang]s1 are problems :i*1 if !y c be solv$1 are ( extreme int]e/ to ! _w at l>ge4 ,9 addition to ! sudd5 & viol5t movem5ts :i* we call e>?quakes1 ! seismologi/ has to inve/igate ! small] motions :i* we call e>? tremors4 ,f obs]vations :i* h be5 made ( late ye>s1 x w\ld appe> t ! gr\nd on :i* we dwell is incessantly 9 a /ate ( tremul\s motion4 ,a fur!r subject ( inve/igation :i* is be=e ! seismologi/ is ! exp]im5tal v]ification ( ! exi/5ce ( :at may be call$ #8e>?-pulsations4' ,^! are motions :i* ma!matical physici/s affirm$ ! exi/5ce (1 b :i*1 9 consequ5ce ( ! sl[ness ( _! p]iod1 h hi!rto escap$ obs]vation4 ,! oscillations1 or sl[ *anges 9 ! relative positions ( l& & sea1 might also be includ$2 b ?is has already be5 tak5 up z a sep>ate bran* ( geology4 ,^! f\r classes ( movem5ts are no d\bt int]dep5d5t1 & seismology 9 ! wide/ s5se might conv5i5tly be employ$ to include !m all4 ,9 succe$+ *apt]s we w endeav\r to indicate h[ f> ! fir/ ?ree ( ^! bran*es h be5 prosecut$1 & to po9t out t :i* rema9s to be accompli%$4 ,x is difficult1 h[ev]1 to =m a j e/imate ( ! am\nt ( seismological "w :i* has be5 done1 9 consequ5ce ( ! scatt]$ & unc]ta9 nature ( _m ( ! records4 ,seismology1 z a sci5ce1 orig9at$ late1 *iefly ow+ to ! facts t c5tres ( civilisation are seldom 9 ! mo/ di/urb$ regions1 & t e>?quake-%ak5 c\ntries are widely sep>at$ f ea* o!r4 ,z e portion ( ! habitable globe appe>s to h be5 %ak5 m or less by e>?quakes1 & z ^! ph5om5a are s t]rible 9 _! nature1 we c readily und]/& :y seismological lit]ature is ext5sive4 ,9 ! annals ( almo/ e c\ntry :i* has a writt5 hi/ory1 ref]5ces are made to seismic di/urbances4 ,an idea ( ! att5tion :i* e>?quakes h receiv$ may be ga!r$ f ! fact t ,pr(essor ,alexis ,p]rey1 ( ,dijon1 :o has publi%$ "s sixty memoirs on ?is subject1 gave1 9 #ahef1 a catalogue ( #a1hcg works devot$ to seismology4#a ,9 #aheh ,mr4 ,rob]t ,mallet publi%$ 9 ! ,reports ( ! ,briti% ,association a li/ ( sev]al hundr$ works relat+ to e>?quakes4 ,sixty-five ( ^! works are to be f\nd 9 ! ,briti% ,museum4 ,s f> z lit]ature is conc]n$1 e>?quakes h receiv$ z mu* att5tion 9 ! ,ea/ z 9 ! ,we/4 ,9 ,*9a !re are _m works treat+ on e>?quakes1 & ! att5tion :i* ^! ph5om5a receiv$ may be judg$ ( f ! fact t 9 ,a4,d4 #acf ! ,gov]nm5t appo9t$ a commission to inquire into ! subject4 ,ev5 ! isolat$ empire ( ,japan c boa/ ( at lea/ sixty-five works on e>?quakes1 sev5 ( :i* are e>?quake cal5d>s1 & tw5ty-?ree e>?quake monographs4#b ,besides ^? treat+ especially ( e>?quakes1 !re are innum]able ref]5ces to su* di/urbances 9 v>i\s hi/ories1 9 ! transactions ( le>n$ societies1 & 9 p]iodicals4 ,to attempt to give a complete catalogue ( ev5 ! books :i* h be5 writt5 w\ld be to ent] on a "w ( compilation :i* w\ld occupy _m ye>s1 & c\ld nev] be satisfactorily f9i%$4 ,9 ! #8,philosophical ,transactions ( ! ,royal ,society1' :i* 7 issu$ 9 ! eighte5? c5tury1 !re are ab\t "o hundr$ & eighty sep>ate communications on e>?quakes2 & 9 ! #8,g5tleman's ,magaz9e' = #agee !re are no less ?an fifty notes & articles on ! same subject4 ,! great int]e/ %[n 9 e>?quakes ab\t ! ye>s #agej-fj 9 ,engl&1 0 *iefly due to ! t]rible calamity :i* ov]took ,lisbon 9 #agee1 & to ! fact t ab\t ?is "t sev]al %ocks 7 exp]i5c$ 9 v>i\s p>ts ( ! ,briti% ,isl&s4 ,9 #agej1 :i* may be describ$ z ! e>?quake ye> ( ,brita91 #8a %ock 0 felt 9 ,surrey on ,m>* #ad2 on ! #ah? ( ! same mon? ! :ole ( ! s\?-we/ ( ,engl& 0 di/urb$4 ,on ,april #b1 ,*e/] 0 %ak52 on ,june #g1 ,norwi* 0 di/urb$2 on ,augu/ #bc1 ! inhabitants ( ,lanca%ire 7 al>m$2 & on ,septemb] #cj ludicr\s & al>m+ sc5es occurr$ 9 consequ5ce ( a %ock hav+ be5 felt dur+ ! h\rs ( ,div9e s]vice1 caus+ ! congregations to hurry into ! op5 air4'#c ,z might be expect$1 ^! occurr5ces gave rise to _m articles & notes direct+ att5tion to ! subject ( e>?quakes4 ,seismic lit]ature has n1 h[ev]1 at all times be5 a measure ( seismic activity3 ?us1 9 ,japan1 ! e>?quake records = ! twelf? & sixte5? c5turies sc>cely m5tion any %ocks4 ,at fir/ sight x might be imag9$ t ?is 0 ow+ to an abs5ce ( e>?quakes2 b x is suffici5tly acc\nt$ = by ! fact t at t "t ! c\ntry 0 torn ) civil w>1 & matt]s m urg5t ?an ! record+ ( natural ph5om5a engag$ ! att5tion ( ! inhabitants4 ,pr(essor ,rockwood1 :o has giv5 s mu* att5tion to seismic di/urbances 9 ,am]ica1 tells u t dur+ ! rec5t conte/ betwe5 ,*ili & ,p]u a simil> int]mission is obs]vable4 ,we see1 !re=e1 t an abs5ce ( records does n necess>ily imply an abs5ce ( ! ph5om5a to be record$4 ,p]haps ! e>lie/ exi/+ records ( e>?quakes are ^? :i* occur 9 ! ,bible4 ,! fir/ ( ^!1 :i* we are told occurr$ 9 ,pale/9e1 0 9 ! reign ( ,ahab 7,b4,c4 #iah-hig74d ,"o ( ! mo/ t]rible e>?quakes m5tion$ 9 ! ,bible is t :i* took place 9 ! days ( ,uzziah1 k+ ( ,judah 7,b4,c4 #haa-gei71 :i* %ook ! gr\nd & r5t ! ,temple4 ,! awful "* ( ?is1 & ! deep impression produc$ on m5's m9ds1 may be le>n$ f ! fact t ! "t ( its occurr5ce 0 subsequ5tly us$ z an epo* f :i* to reckon dates4 ,! writ+s ( ,h]odotus1 ,pl9y1 ,livy1 c41 c41 %[ ! int]e/ :i* e>?quakes attract$ 9 e>ly ages4 ,^! writ]s *iefly devot$ !mselves to ref]5ces & descriptions ( disa/r\s %ocks1 & to !ories respect+ ! cause ( e>?quakes4 ,! great] portion ( ! ,japanese notices ( e>?quakes is simply a s]ies ( anecdotes ( ev5ts :i* took place at ! "t ( ^! disa/]s4 ,we also f9d ref]5ces to sup]/iti\s beliefs1 curi\s occurr5ces1 & ! app>5t connection betwe5 e>?quake di/urbances & o!r natural ph5om5a4 ,9 ^! respects ! lit]ature ( ! ,ea/ closely resembles t ( ! ,we/4 ,! e>?quake cal5d>s ( ! ,ea/1 h[ev]1 =m a class ( books :i* c h>dly be said to f9d _! p>allel 9 ,europe2#e :ile1 on ! o!r h&1 ! latt] possesses types ( books & pamphlets :i* d n appe> to h a p>allel else:]e4 ,^! are ! m or less !ological works--#8,moral ,reflections on ,e>?quakes1' #8,s]mons' :i* h be5 prea*$ on e>?quakes1 #8,pray]s' :i* h be5 appo9t$ to be read4#f ,speak+ g5]ally1 x may be said t ! writ+s ( ! anci5ts1 & ^? ( ! ,middle ,ages1 d[n to ! comm5cem5t ( ! n9ete5? c5tury1 t5d$ to ! propagation ( sup]/ition & to !ories bas$ on speculations ) few & imp]fect facts = _! f\ndation4 ,among ! ef=ts :i* h be5 made 9 mod]n times to raise seismology to a high] level1 is t ( ,pr(essor ,p]rey1 ( ,dijon1 :o comm5c$ 9 #ahdj a s]ies ( ext5sive catalogues embrac+ ! e>?quakes ( ! _w4 ,^! catalogues enabl$ ,p]rey1 & subsequ5tly ,mallet 9 8 reports to ! ,briti% ,association1 to discuss ! p]iodicity ( e>?quakes1 ) ref]5ce to ! seasons & to o!r ph5om5a1 9 a m g5]al mann] ?an x _h be5 possible = previ\s work]s to accompli%4 ,! facts ?us accumulat$ also enabl$ ,mallet to discuss e>?quakes 9 g5]al1 & ! v>i\s ph5om5a :i* !y pres5t 7 sift$ & classifi$ = inspection4 ,ano!r great impetus :i* obs]vational seismology receiv$ 0 ,mr4 ,mallet's report ^u ! ,neapolitan e>?quake ( #aheg1 9 :i* new me?ods ( seismic inve/igation 7 put =?4 ,^! h =m$ ! work+ tools ( _m subsequ5t obs]v]s1 & by !m1 z well z by 8 exp]im5ts on artificially produc$ di/urbances1 ,mallet f9ally drew ! /udy ( e>?quakes f ! realms ( speculation by %[+ t !y1 l o!r natural ph5om5a1 7 capable ( be+ und]/ood & inve/igat$4 ,9 addition to ,p]rey & ,mallet1 ! n9ete5? c5tury has produc$ _m writ]s :o h tak5 a consid]able %>e 9 ! advancem5t ( seismology4 ,!re are ! catalogues ( ,von ,h(f1 ! obs]vations ( ,humboldt1 ! !oretical inve/igations ( ,hopk9s1 ! monographs ( ,s*midt1 ,seeba*1 ,lasaulx1 & o!rs2 ! books ( ,fu*s1 ,cr$n]1 ,vogt1 ,volg]2 ! records & obs]vations ( ,palmi]i1 ,b]telli1 ,rossi1 & o!r ,italian obs]v]s4 ,to ^!1 :i* are only a few out ( a long li/ ( names1 may be add$ ! publications ( ! ,commission appo9t$ = ! obs]vation ( e>?quakes by ! ,natural ,hi/ory ,society ( ,switz]l&1 & ! volumes :i* h be5 publi%$ by ! ,seismological ,society ( ,japan4 ,be=e conclud+ ?is *apt] x w be well to def9e a few ( ! m ord9>y t]ms :i* are us$ 9 describ+ e>?quake ph5om5a4 ,x may be obs]v$ t ! ,engli% ^w e>?quake1 ! ,g]man erdbeb51 ! ,fr5* tremblem5t de t]re1 ! ,spani% t]remoto1 ! ,japanese ji%9 c41 all mean1 :5 lit]ally translat$1 e>?-%ak+1 & are popul>ly und]/ood to mean a sudd5 & m or less viol5t di/urbance4 ,seismology 7 an e>?quake1 a disc\rse7 9 its simple/ s5se means ! /udy ( e>?quakes4 ,to be consi/5t ) a ,greek basis = seismological t]m9ology1 "s writ]s h ?r[n aside ! famili> expression #8e>?quake1' & sub/itut$ ! awkw>d ^w #8seism4' ,! s\rce f :i* an e>?quake orig9ates is call$ ! #8orig91' #8focal cavity1' or #8c5trum4' ,! po9t or area on ! surface ( ! gr\nd above ! orig9 is call$ ! #8epic5trum4' ,! l9e jo9+ ! c5trum & epic5trum is call$ ! #8seismic v]tical4' ,! radial l9es along :i* an e>?quake may be propagat$ f ! c5trum are call$ #8wave pa?s4' ,! angle :i* a wave pa?1 :]e x rea*es ! surface ( ! e>?1 makes ) t surface is call$ ! #8angle ( em]g5ce' ( ! wave4 ,?is angle is usually d5ot$ by ! lett] e4 ,z ! result ( a simple explosion at a po9t 9 a homog5e\s m$ium1 we ought1 !oretically1 to obta9 at po9ts on ! surface ( ! m$ium equidi/ant f ! epic5trum1 equal me*anical effects4 ,^! po9ts w lie on circles call$ #8isoseismic' or #8coseismic' circles4 ,! area includ$ betwe5 two su* circles is an #8isoseismic area4' ,9 nature1 h[ev]1 isoseismic l9es are seldom circles4 ,elliptical or irregul> curves are ! common =ms4 ,! isoseismic area 9 :i* ! greate/ di/urbance has tak5 place is call$ ! #8meizoseismic area4' ,seeba* calls ! l9es enclos+ ?is area #8plei/osei/s4' ,^! la/-m5tion$ l9es are :olly due to ,mallet & ,seeba*4 ,_m words are us$ to di/+ui% diff]5t k9ds ( e>?quakes f ea* o!r4 ,all ( ^! appe> to be v indef9ite & to dep5d ^u ! obs]v]'s feel+s1 :i*1 9 turn1 dep5d ^u 8 n]v\s temp]am5t & 8 situation4 ,9 ,s\? ,am]ica small e>?quakes1 consi/+ ( a s]ies ( rapidly recurr+ vibratory movem5ts n suffici5tly p[]ful to create damage1 are spok5 ( z trembelores4 ,! t]remotos ( ,s\? ,am]ica are e>?quakes ( a de/ructive nature1 9 :i* di/9ct %ocks are p]ceptible4 ,x may be obs]v$ t %ocks :i* at "o place w\ld be describ$ z t]remoto w\ld at ano!r & m di/ant place probably be describ$ z trembelores4 ,! succussatore are ! %ocks :]e !re is consid]able v]tical motion4 ,! t]rible %ock ( ,riobamba 7,febru>y #d1 #agig71 :i* is said to h ?r[n corpses f _! graves to a height ( #ajj feet1 0 an e>?quake ( ?is ord]4 ,! vorticosi are %ocks :i* h a twi/+ or rotatory motion4 ,ano!r me?od ( describ+ e>?quakes w\ld be to ref] to in/rum5tal records4 ,:5 ! vibrations ( ! gr\nd h only be5 along ! l9e jo9+ ! obs]v] & ! epic5trum1 ! di/urbance might be call$ #8eu?utropic4' ,a di/urbance 9 :i* ! prom95t movem5ts are transv]se to ! above direction might be call$ #8diagonic4' ,if motions 9 bo? ( ^! directions occur 9 ! records1 ! %ock might be said to be #8dia/rophic4' ,if !re be mu* v]tical movem5t1 ! %ock might be said to be #8anaseismic4' ,"s di/urbances c\ld only be describ$ by us+ two or ?ree ( ^! t]ms4 ,,*apt] ,,ii4 ,,seismometry4 ,nature ( e>?quake vibrations--,_m in/rum5ts call$ seismomet]s only seismoscopes--,ea/]n seismoscopes1 columns1 projection seismomet]s--,vessels fill$ ) liquid--,palmi]i's m]cury tubes--,! %ip seismoscope--,! cacciatore--,p5dulum in/rum5ts ( ,kreil1 ,wagn]1 ,ew+1 & ,gray--,bracket seismographs--,we/'s p>allel motion in/rum5t--,gray's conical p5dulums1 roll+ sph]es1 & cyl9d]s--,v]beck's ball & plate seismograph--,! pr9ciple ( ,p]ry & ,ayrton--,v]tical motion in/rum5ts--,record receiv]s--,"t-record+ app>atus--,! ,gray & ,milne seismograph4 ,be=e we discuss ! nature ( e>?quake motion1 ! det]m9ation ( :i* has be5 ! aim ( mod]n seismological inve/igation1 ! read] w naturally look = an acc\nt ( ! v>i\s in/rum5ts :i* h be5 employ$ = record+ su* di/urbances4 ,a description ( ! e>?quake ma*9es :i* h be5 us$ ev5 9 ,japan w\ld =m a bulky volume4 ,all t we c d1 !re=e1 is to describe briefly ! m prom95t features ( a few ( ! m important ( ^! in/rum5ts4 ,9 ord] t ! relative m]its ( ^! may be bett] und]/ood1 we may /ate g5]ally t mod]n rese>* has %[n a typical e>?quake to consi/ ( a s]ies ( small tremors succe$$ by a %ock1 or s]ies ( %ocks1 sep>at$ by m or less irregul> vibrations ( ! gr\nd4 ,! vibrations are (t5 bo? irregul> 9 p]iod & 9 amplitude1 & !y h a duration ( f a few seconds to sev]al m9utes4 ,we w illu/rate ! records ( actual e>?quakes 9 a future *apt]1 b 9 ! meantime ! idea t an e>?quake consi/s ( a s+le %ock mu/ be dismiss$ f ! imag9ation4 ,to con/ruct an in/rum5t :i* at ! "t ( an e>?quake %all move & leave a record ( its motion1 !re is b little difficulty4 ,contrivances ( ?is ord] are call$ seismoscopes4 ,if1 h[ev]1 we wi% to "k ! p]iod1 ext5t1 & direction ( ea* ( ! vibrations :i* con/itutes an e>?quake1 we h consid]able difficulty4 ,in/rum5ts :i* w 9 ?is way measure or write d[n ! e>?'s motions are call$ seismomet]s or seismographs4 ,_m ( ! elaborate in/rum5ts supplem5t$ ) electro-magnetic & clockwork arrangem5ts are1 :5 we exam9e !m1 no?+ m ?an elaborate seismoscopes :i* h be5 errone\sly t]m$ seismographs4 ,! only approximations to true seismographs :i* h yet be5 inv5t$ are )\t d\bt ^? :i* dur+ ! pa/ few ye>s h be5 us$ 9 ,japan4 ,x w\ld be a some:at arbitr>y proce$+1 h[ev]1 to classify ! diff]5t in/rum5ts z seismoscopes1 seismomet]s1 & seismographs1 z ! "* ( ! record giv5 by c]ta9 in/rum5ts is sometimes only seismoscopic1 :il/ at o!r times x is seismometric1 dep5d+ on ! nature ( ! di/urbance4 ,_m in/rum5ts1 = in/ance1 w\ld record ) consid]able accuracy a s+le sudd5 movem5t1 b w\ld give no reliable in=mation reg>d+ a cont9u$ %ak+4 ,ea/]n ,seismoscopes4--,! e>lie/ seismoscope ( :i* we f9d any hi/orical record is "o :i* owes its orig9 to a ,*9ese call$ ,*ko4 ,x 0 inv5t$ 9 ! ye> ,a4,d4 #acf4 ,a description is giv5 9 ! ,*9ese hi/ory call$ #8,gokanjo1' & ! translation ( ?is description runs z foll[s3-- #8,9 ! fir/ ye> ( ,yka1 ,a4,d4 #acf1 a ,*9ese call$ ,*ko inv5t$ ! seismomet] %[n 9 ! accompany+ draw+4 ,?is in/rum5t consi/s ( a sph]ically =m$ copp] vessel1 ! diamet] ( :i* is eight feet4 ,x is cov]$ at its top1 & 9 =m resembles a w9e-bottle4 ,its out] "p is ornam5t$ by ! figures ( diff]5t k9ds ( birds & animals1 & old peculi>-look+ lett]s4 ,9 ! inn] "p ( ?is in/rum5t a column is s susp5d$ t x c move 9 eight directions4 ,also1 9 ! inside ( ! bottle1 !re is an arrangem5t by :i* "s record ( an e>?quake is made accord+ to ! movem5t ( ! pill>4 ,on ! outside ( ! bottle !re are eight dragon heads1 ea* ( :i* holds a ball 9 its m\?4 ,und]nea? ^! heads !re are eight frogs s plac$ t !y appe> to wat* ! dragon's face1 s t !y are ready to receive ! ball if x %\ld be dropp$4 ,all ! arrangem5ts :i* cause ! pill> to knock ! ball out ( ! dragon's m\? are well hidd5 9 ! bottle4' ,illu/ration3 ,,fig4 #a4 #8,:5 an e>?quake occurs1 & ! bottle is %ak51 ! dragon in/antly drops ! ball1 & ! frog :i* receives x vibrates vigor\sly2 any "o wat*+ ?is in/rum5t c easily obs]ve e>?quakes4' ,) ?is arrangem5t1 al?\gh "o dragon may drop a ball1 x is n necess>y = ! o!r sev5 dragons to drop _! balls unless ! movem5t has be5 9 all directions2 ?us we c easily tell ! direction ( an e>?quake4 #8,once ^u a "t a dragon dropp$ its ball )\t any e>?quake be+ obs]v$1 & ! p !re=e ?\ght ! in/rum5t ( no use1 b aft] two or ?ree days a notice came say+ t an e>?quake _h tak5 place at ,rsei4 ,he>+ ( ?is1 ^? :o d\bt$ ! use ( ?is in/rum5t began to believe 9 x aga94 ,aft] ?is +5i\s in/rum5t _h be5 inv5t$ by ,*ko1 ! ,*9ese ,gov]nm5t wisely appo9t$ a secret>y to make obs]vations on e>?quakes4' ,n only is ?is in/rum5t ( int]e/ on acc\nt ( its antiquity1 b x is also ( int]e/ on acc\nt ( ! close resemblance x be>s to _m ( ! in/rum5ts ( mod]n times4 ,ano!r e>?quake in/rum5t also ( ,ea/]n orig9 is ! magnetic seismoscope ( ,japan4 ,on ! night ( ! de/ructive e>?quake ( #ahee1 :i* deva/at$ a great portion ( ,tokio1 ! own] ( a spectacle %op 9 ,asakusa obs]v$ t a magnet dropp$ "s old iron nails & keys :i* _h be5 atta*$ to x4 ,f ?is occurr5ce ! own] ?\ght t ! magnet _h1 9 consequ5ce ( its age1 lo/ its p[]s4 ,ab\t two h\rs aft]w>ds1 h[ev]1 ! great e>?quake took place1 aft] :i* ! magnet 0 obs]v$ to h rega9$ its p[]s4 ,?is occurr5ce l$ to ! con/ruction ( ! seismoscope1 :i* is illu/rat$ 9 a book call$ ! #8,ansei-,kembun-,roku1' or a description ( ! e>?quake ( #ahee1 & examples ( ! in/rum5t are /ill to be se5 9 ,tokio4 ,^! in/rum5ts consi/ ( a piece ( magnetic iron ore1 :i* holds up a piece ( iron l a nail4 ,?is nail is connect$1 by means ( a /r+1 ) a tra9 ( clockwork communicat+ ) an al>m4 ,if ! nail falls a cat* is releas$ & ! clockwork set 9 motion1 & w>n+ giv5 by ! r++ ( a bell4 ,x does n appe> t ?is in/rum5t has ev] act$ ) success4 ,columns4--,"o ( ! commone/ =ms ( seismoscope1 & "o :i* has be5 v widely us$1 consi/s ( a r\nd column ( wood1 metal1 or o!r suitable mat]ial1 plac$1 ) its axis v]tical1 on a level plane1 & surr\nd$ by "s s(t mat]ial su* z loose s& to prev5t x roll+ %\ld x be ov]turn$4 ,! fall ( su* a column indicates t a %ak+ or %ock has tak5 place4 ,attempts h be5 made by us+ a numb] ( columns ( diff]5t sizes to make ^! indications seismometric1 b !y seldom give reliable in=mation ei!r z to int5sity or direction ( %ock4 ,! indications z to int5sity are vitiat$ by ! fact t a long-cont9u$ g5tle %ak+ may ov]turn a column :i* w\ld /& a v consid]able sudd5 %ock1 :ile ! directions 9 :i* a numb] ( columns fall seldom agree ow+ to ! rotational motion imp>t$ to !m by ! %ak+4 ,besides1 ! direction ( motion ( ! e>?quake seldom rema9s 9 ! same azimu? ?r\gh\t ! :ole di/urbance4 ,an extremely delicate1 & at ! same "t simple =m ( seismoscope may be made by propp+ up /rips ( glass1 p9s1 or o!r easily ov]turn$ bodies aga9/ suitably plac$ supports4 ,9 ?is way bodies may be arrang$1 :i*1 al?\gh !y c only fall 9 "o direction1 nev]!less fall ) f> less motion ?an is necess>y to ov]turn any column :i* w /& )\t lat]al support4 ,projection ,seismomet]s4--,closely relat$ to ! seismoscopes & seismomet]s :i* dep5d on ! ov]turn+ ( bodies4 ,mallet has describ$ two sets ( app>atus ^: indications dep5d on ! di/ance to :i* a body is project$4 ,9 "o ( ^!1 :i* consi/$ ( two simil> p>ts arrang$ at "r angles1 two metal balls re/ "o on ea* side ( a /op at ! l[] "p ( two incl9$ _/ l tr\ghs4 ,9 ?is position ea* ( ! balls completes an electric circuit4 ,by a %ock ! balls are project$ or roll$ up ! tr\ghs1 & ! height to :i* !y rise is record$ by a correspond+ int]val 9 ! break ( ! circuits4 ,! v]tical compon5t ( ! motion is measur$ by ! compression ( a spr+ :i* c>ries ! table on :i* ?is arrangem5t re/s4 ,9 ! second app>atus two balls are successively project$1 "o by ! =w>d sw+1 & ! o!r by ! backw>d sw+ ( ! %ock4 ,atta*$ to !m are loose wires =m+ t]m9als ( ! circuits4 ,!y are caught 9 a b$ ( wet s& 9 a metal tr\gh =m+ ! o!r end ( ! circuit4 ,! ?r[ ( ! balls z measur$ 9 ! s&1 & ! diff]5ce ( "t betwe5 _! successive projections z indicat$ by special contrivances connect$ ) ! clos+ ( ! circuits1 enables ! obs]v] to calculate ! direction ( ! wave ( %ock1 its velocity1 & o!r elem5ts connect$ ) ! di/urbance4 ,x w be obs]v$ t ! design ( ?is app>atus assumes ! e>?quake to consi/ ( a di/9ct isolat$ %ock4 ,oldham1 at ! end ( 8 acc\nt ( ! ,ca*> e>?quake ( #ahfi1 recomm5ds ! use ( an in/rum5t bas$ on simil> pr9ciples4 ,9 8 in/rum5t f\r balls l bullets are plac$ 9 not*es cut 9 ! corn]s ( ! upp] end ( a squ>e /ake driv5 into ! gr\nd4 ,vessels fill$ ) liquid4--,ano!r =m ( simple seismoscope is made by p>tially fill+ a vessel ) liquid4 ,! height to :i* ! liquid is wa%$ up ! side ( ! vessel is tak5 z an indication ( ! int5sity ( ! %ock1 & ! l9e jo9+ ! po9ts on :i* maximum motion is indicat$1 is tak5 z ! direction ( ! %ock4 ,if e>?quakes all la/$ = ! same l5g? ( "t1 & consi/$ ( vibrations ( ! same p]iod1 su* in/rum5ts might be ( s]vice4 ,^! in/rum5ts h1 h[ev]1 be5 9 use f an e>ly date4 ,9 #agdb we f9d t b[ls ( wat] 7 us$ to measure ! e>?quakes :i* 9 t ye> al>m$ ! inhabitants ( ,leghorn4 ,ab\t ! same "t ! ,rev4 ,s4 ,*&l]1 writ+ ab\t ! %ock at ,lisbon1 tells u t e>?quakes may be measur$ by means ( a sph]ical b[l ab\t ?ree or f\r feet 9 diamet]1 ! inside ( :i*1 aft] be+ du/$ ov] ) ,b>b]'s puff1 is fill$ v g5tly ) wat]4 ,mallet1 ,babbage1 & ,de la ,b*e h recomm5d$ ! same sort ( contrivance1 b1 not)/&+1 x has ju/ly be5 criticis$ z #8ridicul\s & utt]ly impracticable4'#g ,an important portion ( ,palmi]i's well-kn[n in/rum5t consi/s ( horizontal tubes turn$ up at ! ends & p>tially fill$ ) m]cury4 ,to magnify ! motion ( ! m]cury1 small floats ( iron re/ on its surface4 ,^! are atta*$ by means ( ?reads to a pulley provid$ ) indices :i* move 9 front ( a scale ( degrees4 ,we ?us read (f ! int5sity ( an e>?quake z s _m degrees1 :i* means s _m millimetres ( wa%+ up & d[n ( m]cury 9 a tube4 ,! direction ( movem5t is det]m9$ by ! azimu? ( ! tube :i* gives ! maximum indication1 sev]al tubes be+ plac$ 9 diff]5t azimu?s4 ,?is =m ( in/rum5t appe>s to h be5 sugge/$ by ,mallet1 :o gives an acc\nt ( ! same 9 #ahdf4 ,inasmu* z ! rise & fall ( ! m]cury 9 su* tubes dep5d on its dep? & on ! p]iod ( ! e>?quake toge!r ) its duration1 we see t al?\gh ! results obta9$ f a giv5 in/rum5t may give u means ( mak+ approximate comp>isons z to ! relative int5sity ( v>i\s e>?quakes1 x is v f> f yield+ any absolute measurem5t4 ,ano!r me?od :i* has be5 employ$ to magnify & regi/] ! motions ( liquid 9 a vessel has be5 to float ^u its surface a raft or %ip f :i* a tall ma/ project$4 ,by a slight motion ( ! raft1 ! top ( ! ma/ vibrat$ ?r\gh a consid]able range4 ,?is motion ( ! ma/ z to direction & ext5t 0 !n record$ by suitable contrivances atta*$ to ! top ( ! ma/4 ,a v simple =m ( liquid seismoscope consi/s ( a circul> tr\gh ( wood ) not*es cut r\nd its side4 ,?is is fill$ ) m]cury to ! level ( ! not*es4 ,at ! "t ( an e>?quake ! maximum quantity ( m]cury runs ov] ! not*es 9 ! direction ( greate/ motion4 ,?is in/rum5t1 :i* has long be5 us$ 9 ,italy1 is kn[n z a ,cacciatore1 be+ nam$ aft] its inv5tor4 ,x is a prom95t feature 9 ! collection ( app>atus =m+ ! well-kn[n seismograph ( ,palmi]i4 ,p5dulum in/rum5ts4--,mallet speaks ( p5dulum seismoscopes & seismographs z #8! olde/ probably ( seismomet]s long set up 9 ,italy & s\!rn ,europe4' ,9 #ahda we f9d ^! be+ us$ to record ! e>?quake di/urbances at ,comrie 9 ,scotl&4 ,^! in/rum5ts may be divid$ into two classes3 fir/1 ^? :i* at ! "t ( ! %ock are int5d$ to sw+1 & ?us record ! direction ( movem5t2 & second1 ^? :i* are suppos$ to rema9 at re/ & ?us provide #8/eady po9ts4' ,to obta9 an absolutely #8/eady po9t' at ! "t ( an e>?quake1 has be5 "o ( ! *ief aims ( all rec5t seismological inve/igations4 ,) a /yle or po9t] project+ d[n f ! /eady po9t to a surface :i* is be+ mov$ backw>d & =w>d by ! e>?1 su* a surface has writt5 ^u x by its own motions a record ( ! gr\nd to :i* x is atta*$4 ,conv]sely1 a po9t project+ upw>ds f ! mov+ e>? might be caus$ to write a record on ! body provid+ ! /eady po9t1 :i* 9 ! class ( in/rum5ts n[ to be ref]r$ to is suppos$ to be ! bob ( a p5dulum4 ,x is n difficult to get a p5dulum :i* w sw+ at ! "t ( a mod]ately /rong e>?quake1 b x is some:at difficult to obta9 "o :i* w n sw+ at su* a "t4 ,dur+ ! pa/ few ye>s1 p5dulums v>y+ betwe5 =ty feet 9 l5g? & c>ry+ bobs ( eighty p\nds 9 weight1 & "o-eigh? ( an in* 9 l5g?1 & c>ry+ a gun-%ot1 h be5 exp]im5t$ ) "u a great v>iety ( circum/ances4 ,sometimes ! supports ( ^! p5dulums h be5 z rigid z x is possible to make a /ructure f brick & mort>1 & at o!r times !y h int5tionally be5 made loose & flexible4 ,! indices :i* wrote ! motions ( ^! p5dulums h be5 z v>i\s z ! p5dulums !mselves4 ,a small ne$le slid+ v]tically ?r\gh two small holes1 & re/+ its l[] end on a surface ( smok$ glass1 has on acc\nt ( its small am\nt ( friction be5 p]haps "o ( ! fav\rite =ms ( record+ po9t]s4 ,! free p5dulums :i* h be5 employ$1 & :i* 7 int5d$ to sw+1 h be5 us$ = two purposes3 fir/1 to det]m9e ! direction ( motion f ! direction ( sw+1 & second1 to see if an approximation to ! p]iod ( ! e>?'s motion c\ld be obta9$ by discov]+ ! p5dulum among/ a s]ies ( diff]5t l5g?s :i* 0 set 9 mo/ viol5t motion1 ?is probably be+ ! "o :i* _h its natural p]iod ( sw+ ! mo/ ne>ly approximat+ to ! p]iod ( ! e>?quake oscillations4 ,inasmu* z all p5dulums :5 sw++ h a t5d5cy to *ange ! plane ( _! oscillation1 & also z we n[ "k t ! direction ( motion dur+ an e>?quake is n always con/ant1 ! results usually obta9$ ) ^! in/rum5ts respect+ ! direction ( ! e>?'s motion h be5 unsatisfactory4 ,! results :i* 7 obta9$ by s]ies ( p5dulums ( diff]5t l5g?s 71 = v>i\s reasons1 also unsatisfactory4 ,( p5dulums int5d$ to provide a /eady po9t1 f :i* ! relative motion ( a po9t on ! e>?'s surface c\ld be record$1 !re has be5 a great v>iety4 ,"o ( ! olde/ =ms consi/$ ( a p5dulum ) a /yle project+ d[nw>ds f ! bob s z to t\* a b$ ( s&4 ,sometimes a concave surface 0 plac$ b5ea? ! p5dulum1 on :i* ! record 0 trac$ by means ( a p5cil4 ,probably ! be/ =m 0 t 9 :i* a ne$le1 capable ( slid+ freely up & d[n1 m>k$ ! relative horizontal motion ( ! e>? & ! p5dulum bob on a smok$ glass plate4 ,x g5]ally happ5s t at ! "t ( a mod]ately sev]e e>?quake ! :ole ( ^! =ms ( app>atus are set 9 motion1 due p>tly to ! motion ( ! po9t ( support ( ! p5dulum1 & p>tly to ! friction ( ! writ+ po9t on ! plate4 ,among ^! p5dulums may be m5tion$ ^? ( ,cavalli]i1 ,faura1 ,palmi]i1 ,rossi1 & num]\s o!rs4 ,x is possible t ! orig9ators ( "s ( ^! p5dulums may h int5d$ t !y %\ld record by sw++4 ,if ?is is s1 !n s f> z ! det]m9ation ( ! actual nature ( e>?quake motion is conc]n$1 !y belong to a l[] grade ( app>atus ?an t 9 :i* !y are "h includ$4 ,a great improvem5t 9 p5dulum app>atus is due to ,mr4 ,?omas ,gray ( ,glasg[1 :o sugge/$ apply+ s mu* frictional resi/ance to ! free sw+ ( a p5dulum t = small displacem5ts x became #8dead beat4' ,by c>ry+ out ?is sugge/ion1 p5dulum in/rum5ts 7 rais$ to ! position ( seismographs4 ,! mann] ( apply+ ! friction w be und]/ood f ! foll[+ description ( a p5dulum in/rum5t :i* is also provid$ ) an index :i* gives a magnification ( ! motion ( ! e>?4 ,b ,b ,b ,b is a box #aac cm4 high & #cj cm4 by #ah cm4 squ>e4 ,inside ?is box a lead r+ ,r1 #ag cm4 9 diamet] & #c cm4 ?ick1 is susp5d$ z a p5dulum f ! screw ,s4 ,?is screw passes ?r\gh a small brass plate ,p ,p1 :i* c be mov$ horizontally ov] a hole 9 ! top ( ! box4 ,^! motions 9 ! po9t ( susp5sion all[ ! p5dulum to be adju/$4 ,illu/ration3 ,,fig4 #b4 ,project+ ov] ! top ( ! p5dulum !re is a wood5 arm ,w c>ry+ two slid+ po9t]s ,h ,h1 re/+ on a glass plate plac$ on ! top ( ! p5dulum4 ,^! po9t]s are = ! purpose ( giv+ ! frictional resi/ance be=e ref]r$ to4 ,if ?is friction plate is smok$1 ! friction po9t]s w write ^u x records ( l>ge e>?quakes indep5d5tly ( ! records giv5 by ! prop] index1 :i* only gives satisfactory records 9 ! case ( %ocks ( ord9>y int5sity4 ,cross+ ! inside ( ! p5dulum ,r !re is a brass b> p]=at$ ) a small conical hole at ,m4 ,a /iff wire passes ?r\gh ,m & =ms ! upp] portion ( ! index ,i1 ! l[] portion ( :i* is a ?9 piece ( bamboo4 ,fix$ ^u ! wire !re is a small brass ball :i* re/s on ! upp] side ( a second brass plate also p]=at$ ) a conical hole1 :i* plate is fix$ on ! b> ,o ,o cross+ ! box4 ,if at ! "t ( an e>?quake ! upp] "p ( ! index ,i rema9s /eady at ,m1 !n by ! motion at ,o1 ! l[] end ( ! index :i* c>ries a slid+ ne$le at ,g1 w magnify ! motion ( ! e>? 9 ! ratios ,m ,o3 ,o ,g4 ,9 ?is in/rum5t ,o ,g is ab\t #ag cm4 ,! ne$le ,g works ^u a piece ( smok$ glass4 ,9 ord] to br+ ! glass into contact ) ! ne$le )\t di/urbance1 ! glass is c>ri$ on a /rip ( wood ,k1 h+$ at ! back ( ! box1 & propp$ up 9 front by a loose block ( wood ,y4 ,:5 ,y is remov$ ! glass drops d[n ) ,k out ( contact ) ! ne$le4 ,! box is c>ri$ on b>s ( wood ,c ,c1 :i* are fix$ to ! gr\nd by ! /akes ,a ,a4 ,! great advantage ( a p5dulum seismograph work+ on a /ation>y plate is1 t ! record %[s at once :e!r ! direction ( motion has be5 con/ant1 or :e!r x has be5 v>iable4 ,! maximum ext5t ( motion 9 v>i\s directions is also easily obta9$4 ,! disadvantage ( ! in/rum5t is1 t at ! "t ( a l>ge e>?quake1 ow+ p]haps to a slight sw+ 9 ! p5dulum1 ! records may be unduly magnifi$4 ,on su* occasions1 h[ev]1 fairly good records may be obta9$ f ! friction po9t]s1 provid$ t ! plates on :i* !y "w h be5 previ\sly smok$4 ,x might p]haps be well to use two ( ^! in/rum5ts1 "o hav+ a comp>atively high frictional resi/ance1 & h5ce #8dead beat' = l>ge displacem5ts4 ,_m attempts h be5 made to use a p5dulum seismograph 9 conjunction ) a record-receiv+ surface1 :i* at ! "t ( ! e>?quake %\ld be kept 9 motion by clockwork4 ,9 ?is way x 0 hop$ to sep>ate ! v>i\s vibrations ( ! e>?quake1 & ?us avoid ! great] or less confusion :i* occurs :5 ! index ( ! p5dulum writes its backw>d & =w>d motion on a /ation>y plate4 ,hi!rto all attempts 9 ?is direction1 9 :i* a s+le multiply+ index 0 us$1 h be5 unsuccessful because ( ! mov+ plate dragg+ ! index 9 ! direction ( its motion = a %ort di/ance1 & !n all[+ x to fall back t[>ds its normal position4 ,9 connection ) ?is subject we may m5tion ! p5dulum seismographs ( ,kreil1 ,wag5]1 ,ew+1 & ,gray4 ,9 ! bob ( ,kreil's p5dulum !re 0 clockwork1 :i* caus$ a disc on ! axis ( ! p5dulum to cont9u\sly rotate4 ,on ?is cont9ually revolv+ surface a /yle fix$ to ! e>? trac$ an unbrok5 circle4 ,at ! "t ( an e>?quake1 by ! motion ( ! /yle1 ! circle 0 to be brok5 & l9es drawn4 ,! numb] & l5g? ( ^! l9es 7 to indicate ! l5g? & int5sity ( ! di/urbance4 ,gray's p5dulum consi/$ ( a flat heavy disc c>ry+ on its upp] surface a smok$ glass plate4 ,?is1 :i* =m$ ! bob ( ! p5dulum1 0 support$ by a pian(orte /eel wire4 ,:5 set ready to receive an e>?quake1 ! wire 0 twi/$ & ! bob held by a cat* s arrang$ t at ! "t ( ! e>?quake ! cat* 0 releas$1 & ! bob ( ! p5dulum all[$ to turn sl[ly by ! untwi/+ ( ! support+ wire4 ,re/+ on ! surface ( ?is rotat+ disc 7 two multiply+ indices arrang$ to write ! e>?'s motions z two compon5ts4 ,9 ! in/rum5ts ( ,wag5] & ,ew+1 ! clockwork & mov+ surface d n =m "p ( ! p5dulum1 b re/ indep5d5tly on a support rigidly atta*$ to ! e>?4 ,9 ,wag5]'s in/rum5t "o index only is us$1 :ile 9 ,ew+'s two are us$ = writ+ ! record ( ! motion4 ,a difficulty :i* is app>5t 9 all p5dulum ma*9es is t :5 ! bob ( su* a p5dulum is deflect$ x t5ds to fall back to its normal position4 ,to make a p5dulum p]fect x !re=e requires "s comp5sat+ arrangem5t1 s t ! p5dulum1 = small displacem5ts1 %all be 9 neutral equilibrium1 & ! errors due to sw++ %all be avoid$4 ,sev]al me?ods h be5 sugge/$ = mak+ ! bob ( an ord9>y p5dulum a/atic = small displacem5ts4 ,"o me?od propos$ by ,gray consi/s 9 fix+ 9 ! bob ( a p5dulum a circul> tr\gh ( liquid1 ! curvature ( ?is tr\gh hav+ a prop] =m4 ,ano!r me?od :i* 0 sugge/$1 0 to atta* a v]tical spiral spr+ to a po9t 9 ! axis ( ! p5dulum a little bel[ ! po9t ( susp5sion1 & to a fix$ po9t above x1 s t :5 ! p5dulum is deflect$ x w\ld introduce a c\ple4 ,pr(essor ,ew+ has sugge/$ an arrangem5t s t ! bob ( ! p5dulum %all be p>tly susp5d$ by a /ret*$ spiral spr+1 & at ! same "t %all be p>tly held up f bel[ by a v]tically plac$ /rut1 ! weight c>ri$ by ! /rut be+ to ! weight c>ri$ by ! spr+ 9 ! ratio ( _! respective l5g?s4 ,z to h[ ^! arrangem5ts w act :5 c>ri$ into practice yet rema9s to be se54 ,ano!r important class ( in/rum5ts are inv]t$ p5dulums4 ,^! are v]tical spr+s made ( metal or wood load$ at _! upp] end ) a heavy mass ( metal4 ,an arrangem5t ( ?is sort1 provid$ at its upp] end ) a p5cil to write on a concave surface1 0 employ$ 9 #ahda to regi/] ! e>?quakes at ,comrie 9 ,scotl&4 ,9 ,japan !y 7 l>gely employ$ 9 s]ies1 ea* memb] ( a s]ies hav+ a diff]5t p]iod ( vibration4 ,! object ( ^! arrangem5ts 0 to det]m9e :i* ( ! p5dulums1 ) a giv5 e>?quake1 record$ ! greate/ motion1 x be+ assum$ t ! "o :i* 0 ?r[n into ! mo/ viol5t oscillation w\ld be ! "o mo/ ne>ly approximat+ ) ! p]iod ( ! e>?quake4 ,! result ( ^! exp]im5ts %[$ t x 0 usually ^? ) a sl[ p]iod ( vibration :i* 7 ! mo/ di/urb$4 ,bracket ,seismographs4--,a gr\p ( in/rum5ts ( rec5t orig9 :i* h done good "w1 are ! bracket seismographs4 ,^! in/rum5ts appe> to h be5 indep5d5tly inv5t$ by sev]al inve/igators3 ! g]m f :i* !y orig9at$ probably be+ ! well-kn[n horizontal p5dulum ( ,pr(essor ,zlln]4 ,9 ,japan !y 7 fir/ employ$ by ,pr(essor ,w4 ,s4 ,*apl94 ,subsequ5tly !y 7 us$ by ,pr(essor ,ew+ & ,mr4 ,gray4 ,!y consi/ ess5tially ( a heavy weight support$ at ! extremity ( a horizontal bracket :i* is free to turn on a v]tical axis at its o!r end4 ,:5 ! frame c>ry+ ?is axis is mov$ 9 any direction except+ p>allel to ! l5g? ( ! gate-l bracket1 ! weight causes ! bracket to turn r\nd a l9e kn[n z ! in/antane\s axis ( ! bracket correspond+ to ?is motion ( ! fix$ axis4 ,any po9t 9 ?is l9e may !re=e be tak5 z a /eady po9t = motions at "r angles to ! l5g? ( ! support+ bracket4 ,two ( ^! in/rum5ts plac$ at "r angles to ea* o!r h to be employ$ 9 conjunction1 & ! motion ( ! gr\nd is writt5 d[n z two rectangul> compon5ts4 ,9 ,pr(essor ,ew+'s =m ( ! in/rum5t1 light prolongations ( ! brackets =m indices :i* give magnifi$ repres5tations ( ! motion1 & ! weights are pivot$ r\nd a v]tical axis ?r\gh _! c5tre4 ,9 ! accompany+ sket* ,b is a heavy weight pivot$ at ! end ( a small bracket ,c ,a ,k1 :i* bracket is free to turn on a knife-edge1 ,k1 above1 & a pivot ,a1 bel[1 9 ! /& ,s4 ,at ! "t ( an e>?quake ,b rema9s /eady1 & ! index ,p1 =m+ a cont9uation ( ! bracket1 magnifies ! motion ( ! /&1 9 ! ratio ( ,a ,c 3 ,c ,n4 ,illu/ration3 ,,fig4 #c4 ,9 an in/rum5t call$ a d\ble-bracket seismograph1 inv5t$ by ,mr4 ,gray1 we h two brackets h+$ to ea* o!r1 & "o ( !m to a fix$ frame4 ,! planes ( ! two brackets are plac$ at "r angles1 s z to give to a heavy mass support$ at ! end ( ! out] bracket two degrees ( horizontal fre$om4 ,9 all bracket ma*9es1 especially ^? :i* c>ry a pivot$ weight1 x is d\btful :e!r ! weight provides a truly /eady po9t relatively to ! plate on :i* ! record is writt5 = motion p>allel to ! direction ( ! arm4 ,illu/ration3 ,,fig4 #d4 ,p>allel motion ,in/rum5t4--,a ma*9e :i* writes its record z two compon5ts1 & :i* promises great /ability1 is "o sugge/$ by ,pr(essor ,c4 ,d4 ,we/4 ,l ! bracket ma*9es x consi/s ( two simil> p>ts plac$ at "r angles to ea* o!r1 & is z foll[s3 ,a b> ( iron ,a is susp5d$ f bo? sides on pivots at ,c ,c by a sy/em ( light arms h++ ) ea* o!r at ! black dots1 betwe5 ! upp] & l[] p>ts ( ! rigid frame ,b ,c4 ,! arms are ( su* a l5g? t = small displacem5ts p>allel to ! l5g? ( ! b>1 ,c ,c practically move 9 a /raight l9e1 & ! b> is 9 neutral equilibrium4 ,a light prolongation ( ! b> d works ! upp] end ( ! light index e1 pass+ z a univ]sal jo9t ?r\gh ! rigid support ,f4 ,a second index e f ! b> at "r angles also passes ?r\gh ,f4 ,! multiply+ ends ( ^! indices are c\pl$ toge!r to write a resultant motion on a smok$ glass plate ,s4 ,conical ,p5dulums4--,ano!r gr\p ( in/rum5ts :i* h also yield$ valuable records are ! conical p5dulum seismographs4 ,! idea ( us+ ! bob ( a conical p5dulum to give a /eady po9t 9 an e>?quake ma*9e 0 fir/ sugge/$ & c>ri$ into practice by ,mr4 ,gray4 ,! seismograph z employ$ consi/s ( a pair ( conical p5dulums hung 9 planes at "r angles to ea* o!r4 ,! bob ( ea* ( ^! p5dulums is fix$ a %ort di/ance f ! end ( a light lev]1 :i* =ms ! writ+ index1 ! %ort end re/+ z a /rut aga9/ ! side ( a po/ fix$ 9 ! e>?4 ,! weight is c>ri$ by a ?9 wire or ?read1 ! upp] end ( :i* is atta*$ to a po9t v]tically above ! fix$ end ( ! lev]4 ,roll+ ,sph]es & ,cyl9d]s4--,aft] ! conical p5dulum seismographs1 :i* claim sev]al important advantages ov] ! bracket ma*9es1 we come to a gr\p ( in/rum5ts kn[n z roll+ sph]e seismographs4 ,"h1 aga91 we h a class ( in/rum5ts = ! v>i\s =ms ( :i* we are indebt$ to ! +5uity ( ,mr4 ,gray4 ,! g5]al arrangem5t & pr9ciple ( "o ( ^! in/rum5ts w be readily und]/ood f ! accompany+ figure4 ,s is a segm5t ( a l>ge sph]e ) a c5tre ne> ,c4 ,slightly bel[ ?is c5tre a heavy weight ,b1 :i* may be a lead r+1 is pivot$4 ,at ! "t ( an e>?quake ,c is /eady1 & ! e>?'s motions are magnifi$ by ! po9t] ,c ,a ,n 9 ! proportion ( ,c ,a 3 ,a ,n4 ,! work+ ( ?is po9t] or index is simil> to t ( ! po9t] 9 ! p5dulum4 ,illu/ration3 ,,fig4 #e4 ,closely connect$ ) ! roll+ sph]e seismographs1 are ,gray's roll+ cyl9d] seismographs4 ,^! are two cyl9d]s re/+ on a surface plate ) _! axes at "r angles to ea* o!r4 ,ne> to ! highe/ po9t 9 ea* ( ^! cyl9d]s1 ?is po9t rema9+ ne>ly /eady :5 ! surface plate is mov$ backw>ds & =w>ds1 !re is atta*$ ! end ( a light index4 ,^! indices are aga9 pivot$ a %ort di/ance f _! ends on axes connect$ ) ! surface plate4 ,9 ord] t ! two indices may be br\ght p>allel1 "o is crank$ at ! second pivot4 ,ball & ,plate ,seismograph4--,ano!r =m ( seismograph1 :i* is closely relat$ to ! two =ms ( app>atus j describ$1 is ,v]beck's ball & plate seismograph4 ,?is consi/s ( a surface plate re/+ on ?ree h>d sph]es1 :i* 9 turn re/s ^u a second surface plate4 ,:5 ! l[] plate is mov$1 ! upp] "o t5ds to rema9 at re/1 & ?us may be us$ z a /eady mass to move an index4 ,! ,pr9ciple ( ,p]ry & ,ayrton4--,an in/rum5t :i* is ( int]e/ f ! sci5tific pr9ciple x involves is a seismograph sugge/$ by ,pr(essors ,p]ry & ,ayrton1 :o propose to support a heavy ball on ?ree spr+s1 :i* %all be suffici5tly /iff to h an exce$+ly quick p]iod ( vibration4 ,by means ( p5cils atta*$ to ! ball by lev]s1 ! motions ( ! ball are to be record$ on a mov+ b& ( pap]4 ,! result w\ld be a record comp\nd$ ( ! small vibrations ( ! spr+s sup]impos$ on ! l>g]1 sl[]1 wave-l motions ( ! e>?quake1 &1 kn[+ ! =m] ( ^!1 ! latt] might be sep>at$ by analysis4 ,al?\gh our pres5t k ( e>?quake motion indicates t ! analysis ( su* a record w\ld (t5 pres5t u ) insup]able difficulties1 ?is in/rum5t is wor?y ( notice on acc\nt ( ! novelty ( ! pr9ciple x involves1 :i*1 ! au?ors truly rem>k1 has 9 seismometry be5 a #8neglect$' "o4 ,in/rum5ts to record ,v]tical ,motion4--,! in/rum5ts :i* h be5 devis$ to record v]tical motion are almo/ z num]\s z ^? :i* h be5 devis$ to record horizontal motion4 ,! e>lie/ =m ( in/rum5t employ$ = ?is purpose 0 a spiral spr+ /ret*$ by weight1 :i*1 on acc\nt ( its in]tia1 0 suppos$ at ! "t ( a %ock to rema9 /eady4 ,no satisfactory results h ev] be5 obta9$ f su* in/rum5ts1 *iefly on acc\nt ( ! inconv5i5ce 9 mak+ a spr+ suffici5tly long to all[ ( en\gh elongation to give a long p]iod ( vibration4 ,simil> rem>ks may be appli$ to ! horizontally plac$ ela/ic rods1 "o end ( :i* is fix$ to a wall1 :il/ ! opposite end is load$ ) a weight4 ,su* contrivances1 furni%$ ) p5cil on ! weight to write a record ^u a v]tical surface1 7 us$ 9 #ahdb at ,comrie1 & we see ! same pr9ciple appli$ 9 a portion ( ,palmi]i's app>atus4 ,contrivances l ^! nei!r give u ! true amplitude ( ! v]tical motion1 insomu* z !y are readily set 9 a /ate ( oscillation2 nor d !y indicate ! duration ( a di/urbance1 =1 be+ once set 9 motion1 !y cont9ue t motion 9 virtue ( _! in]tia long aft] ! actual e>?quake has ceas$4 ,!y c only be reg>d$ z seismoscopes4 ,illu/ration3 ,,fig4 #f4 ,! mo/ satisfactory in/rum5t :i* has yet be5 devis$ = record+ v]tical motion is ,gray's horizontal lev] spr+ seismograph4 ,?is in/rum5t w be bett] und]/ood f ! accompany+ sket*4 ,a v]tical spr+ ,s is fix$ at its upp] end by means ( a nut n1 :i* re/s on ! top ( ! frame ,f1 & s]ves to raise or l[] ! spr+ ?r\gh a %ort di/ance z a la/ adju/m5t = ! position ( ! cross-arm ,a4 ,! arm ,a re/s at "o end on two %>p po9ts1 p1 "o re/+ 9 a conical hole & ! o!r 9 a ,v-slot2 x is support$ at ,b by ! spr+ ,s1 & is weight$ at ,c ) a lead r+ ,r4 ,ov] a p9 at ! po9t ,c a /irrup ( ?read is plac$ :i* supports a small tr\gh1 t4 ,! tr\gh t is pivot$ at a1 has atta*$ to x ! index i 7:i* is h+$ by means ( a /rip ( t\gh pap] at h1 & re/s ?r\gh a f9e p9 on ! glass plate g71 & is p>tly fill$ ) m]cury4 ,ano!r me?od ( obta9+ a /eady po9t = v]tical motion is t ( ,dr4 ,wag5]1 :o employs a buoy p>tly imm]s$ 9 a vessel ( wat]4 ,?is 0 consid]ably improv$ ^u by ,mr4 ,gray1 :o sugge/$ ! use ( a buoy1 :i*1 ) ! exception ( a long ?9 /yle1 0 completely sunk4 ,among ! o!r =ms ( app>atus us$ to record v]tical motion may be m5tion$ vessels provid$ ) india-rubb] or o!r flexible bottoms1 & p>tially fill$ ) wat] or "s o!r liquid4 ,z ! vessel is mov$ up & d[n1 ! bottom t5ds to rema9 beh9d & provides a m or less /eady po9t4 ,pivot$ to ?is is a light index1 :i* is aga9 pivot$ to a rigid frame 9 connection ) ! e>?4 ,in/rum5ts ( ?is description h yield$ good records4 ,record ,receiv]s4--,a l>ge numb] ( e>?quake ma*9es hav+ be5 ref]r$ to1 x n[ rema9s to consid] ! app>atus on :i* !y write _! motions4 ,! e>li] =ms ( seismographs1 z has already be5 indicat$1 record$ _! movem5ts 9 a b$ ( s&2 o!rs wrote _! records by means ( p5cils on %eets ( pap]4 ,:]e we h seismographs :i* magnify ! motion ( ! e>?1 x w be obs]v$ t me?ods l ! above w\ld involve great frictional resi/ances1 t5d+ to cause motion 9 ! assum$ /eady po9ts ( ! seismographs4 ,"o ( ! mo/ p]fect in/rum5ts w\ld be obta9$ by regi/]+ photographically ! motions ( ! record+ index by ! reflection ( a ray ( light4 ,su* an in/rum5t w\ld1 h[ev]1 be difficult to con/ruct & difficult to manipulate4 ,"o ( ! be/ practical =ms ( regi/]+ app>atus is "o 9 :i* ! record is writt5 on a surface ( smok$ glass4 ,?is c aft]w>ds be cov]$ ) a coat ( photograph]'s v>ni%1 & subsequ5tly photograph$ by ! #8blue process' s well kn[n to eng9e]s4 ,to obta9 a record ( all ! vibrations ( an e>?quake x is necess>y t ! surface on :i* ! seismograph writes %\ld at ! "t ( an e>?quake be 9 motion4 ,( record-receiv+ ma*9es !re are ?ree types4 ,fir/1 !re are ^? :i* move cont9u\sly4 ,! common =m ( ^! is a circul> glass plate l an old =m ( *ronograph1 driv5 cont9u\sly by clockwork4 ,on ?is ! po9t]s ( ! seismograph re/ & trace ov] & ov] aga9 ! same circles4 ,at ! "t ( an e>?quake !y move back & =? across ! circles1 :i* are !oretically f9e l9es1 & leave a record ( ! e>?quake4 ,in/ead ( a circul> plate1 a drum cov]$ ) smok$ pap] may be us$1 :i*1 aft] ! e>?quake1 possesses ! advantage1 aft] unroll+1 ( pres5t+ ! record 9 a /raight l9e1 in/ead ( a record writt5 r\nd ! p]iph]y ( a circle1 z is ! case ) ! circul> glass plates4 ,su* records are easily pres]v$1 b !y are m difficult to photograph4 ,! second =m ( app>atus is "o :i* is set 9 motion at ! "t ( a %ock4 ,?is may be a contrivance l "o ( ^? j describ$1 or a /raight smok$ glass plate on a c>riage4 ,by means ( an electrical or a me*anical contrivance call$ a #8/>t]1' ( :i* _m =ms h be5 contriv$1 ! e>?quake is caus$ to release a det5t & ?us set 9 motion ! me*anism :i* moves ! record receiv]4 ,! great advantage ( cont9u\sly-mov+ ma*9es is t ! beg9n+ & end ( ! %ock c usually be got ) c]ta9ty1 :ile all ! unc]ta9ty z to ! action ( ! #8/>t]' is avoid$4 ,self-/>t+ ma*9es h1 ( c\rse1 ! advantage ( simplicity & *eapness1 :ile !re is no dang] ( ! record gett+ oblit]at$ by ! subsequ5t motion ( ! plate "u ! index4 ,"t-record+ ,app>atus4--,( equal importance ) ! in/rum5ts :i* record ! motion ( ! gr\nd1 are ^? in/rum5ts :i* record ! "t at :i* su* motion took place4 ,! great value ( "t records1 :5 det]m9+ ! orig9 f :i* an e>?quake orig9ates1 w be %[n f>!r on4 ,! mo/ important result :i* is requir$ 9 connection ) "t obs]vations1 is to det]m9e ! int]val ( "t tak5 by a di/urbance 9 travell+ f "o po9t to ano!r4 ,on acc\nt ( ! great velocity ) :i* ^! di/urbances sometimes travel1 x is necess>y t ^! obs]vations %\ld be made ) consid]able accuracy4 ,! old me?ods ( adapt+ an app>atus to a clock :i*1 :5 %ak51 %all cause ! clock to /op1 are ( little value unless ! /ations at :i* ! obs]vations are made are at consid]able di/ances ap>t4 ,?is w be appreciat$ :5 we rememb] t ! di/urbance may possibly travel at ! rate ( a mile p] second1 t its duration at any /ation may (t5 ext5d ov] a m9ute1 & t "o set ( app>atus at "o /ation may /op1 p]haps1 at ! comm5cem5t ( ! di/urbance1 & ! o!r ne> ! end4 ,a satisfactory "t-tak+ app>atus w !re=e require1 n only ! means = /opp+ a clock1 b also a contrivance :i*1 at ! same in/ant t ! clock is /opp$1 %all make a m>k on a record :i* is be+ drawn by a seismograph4 ,9 ?is way we f9d out at :i* portion ( ! %ock ! "t 0 tak54 ,illu/ration3 ,,fig4 #g4 ,palmi]i /ops a clock 9 8 seismograph by clos+ an electric circuit4 ,mallet proposes to /op a clock by ! fall+ ( a column :i* is atta*$ by a /r+ to ! p5dulum ( ! clock4 ,s long z ! column is /&+ ! /r+ is loose & ! p5dulum is free to move2 b :5 ! column falls1 ! /r+ is tight5$ & ! p5dulum is arre/$4 ,! difficulty :i* arises is to obta9 a column t w fall ) a slight di/urbance4 ,! be/ =m ( contrivance = caus+ a column to fall1 & "o :i* may also be us$ 9 draw+ out a cat* to relieve ! ma*9]y ( a record receiv]1 is %[n 9 ! accompany+ sket*4 ,s is ! segm5t ( a sph]e ab\t #de cm4 radius1 ) a c5tre slightly above ,c4 ,l is a disc ( lead ab\t #g cm4 9 diamet] re/+ ^u ! segm5t4 ,above ?is !re is a light po9t]1 ,p1 ab\t #cj cm4 long4 ,on ! top ( ! po9t] a small cyl9d] ( iron1 ,w1 is balanc$1 & connect$ by a /r+ ) ! cat* to be reliev$4 ,:5 ! table on :i* ,w ,p ,s re/s is %ak51 rotation takes place ne> to ,c1 ! motion ( ! base ,s is magnifi$ at ! upp] end ( ! po9t]1 & ! weight ov]turn$4 ,?is cat* may be us$ to relieve a too!d b> axl$ at "o end1 & held up above a p9 project+ f ! face ( ! p5dulum bob4 ,:5 ?is falls x cat*es ! project+ p9 & holds ! p5dulum4 ,ano!r way ( reliev+ ! too!d b> is to hold up ! opposite end to t at :i* x is axl$ by re/+ x on ! extremity ( a horizontal wire fix$ to ! bob ( a conical p5dulum--= example1 "o ( ! indices ( a conical p5dulum seismograph4 ,! :ole ( ?is app>atus1 :i* may be con/ruct$ at ! co/ ( a few p5ce1 c be made small en\gh to g inside an ord9>y clock case4 ,! difficulty :i* arises ) all ^! clock-/opp+ arrangem5ts is t x is difficult = obs]v]s situat$ at di/ant /ations to re-/>t _! clocks s t _! diff]5ce 9 "t %all be accurately kn[n4 ,ev5 if ea* obs]v] is provid$ ) a well-regulat$ *ronomet]1 ) :i* he c make comp>isons1 ! rat+ ( ^! in/rum5ts is = all ord9>y p]sons an extremely tr\blesome op]ation4 ,9 ord] to avoid ?is difficulty ! au?or has ( late ye>s us$ a me?od ( obta9+ ! "t )\t /opp+ ! clock4 ,to d ?is a clock ) a c5tral seconds h& is tak51 & ! h\r & m9ute h&s are prolong$ & b5t out slightly at _! extremities at "r angles to ! face1 ! h\r h& be+ slightly ! longe/4 ,ea* h& is !n tipp$ ) a piece ( s(t mat]ial l cork1 :i* is sme>$ ) a glyc]9e ink4 ,a light flat r+1 ) divisions 9 x correspond+ to ^? on ! face ( ! clock1 is s arrang$ t at ! "t ( a %ock x c be quickly advanc$ to t\* ! ink$ pads on ! h&s ( ! clock & !n )drawn4 ,?is is accompli%$ by suitable ma*9]y1 :i* is reliev$ ei!r by an electro-magnet or "s o!r contrivance :i* w )draw a cat*4 ,9 ?is way an impression 9 ! =m ( ?ree dots is receiv$ on ! disc1 & ! "t kn[n )\t ei!r /opp+ or s5sibly ret>d+ ! clock4 ,= ord9>y obs]v]s1 if a "t-tak] is n us$ 9 conjunction ) a record receiv]1 z good results z ^? obta9$ by ord9>y clock-/opp+ app>atus are obta9able by glanc+ at an ord9>y wat*4 ,subsequ5tly ! wat* by :i* ! obs]vation 0 made %\ld be comp>$ ) "s good "t-keep]1 & ! local "t at :i* ! %ock took place is !n approximately kn[n4 ,f :at has n[ be5 said x w be se5 t = a complete seismograph we require ?ree di/9ct sets ( app>atus--an app>atus to record horizontal motion1 an app>atus to record v]tical motion1 & an app>atus to record "t4 ,! horizontal & v]tical motions mu/ be writt5 on ! same receiv]1 & if possible side by side1 :il/ ! in/ant at :i* ! "t record is made a m>k mu/ be made on ! edge ( ! diagram :i* is be+ drawn by ! seismograph4 ,su* a seismograph has be5 con/ruct$ & is n[ erect$ 9 ,japan4 ,x is illu/rat$ 9 ! accompany+ diagram4 ,! ,gray & ,milne ,seismograph4--,9 ?is app>atus two mutually rectangul> compon5ts ( ! horizontal motion ( ! e>? are record$ on a %eet ( smok$ pap] w\nd r\nd a drum1 ,d1 kept cont9u\sly 9 motion by clockwork1 ,w1 by means ( two conical p5dulum seismographs1 ,c4 ,! v]tical motion is record$ on ! same %eet ( pap] by means ( a comp5sat$-spr+ seismograph1 ,s ,l ,m ,b4 ,! "t ( occurr5ce ( an e>?quake is det]m9$ by caus+ ! circuit ( two electro-magnets to be clos$ by ! %ak+4 ,"o ( ^! magnets relieves a me*anism1 =m+ "p ( a "t-keep]1 :i* causes ! dial ( ! timepiece to come sudd5ly =w>ds on ! h&s & !n move back to its orig9al position4 ,! h&s are provid$ ) ink-pads1 :i* m>k _! positions on ! dial1 ?us indicat+ ! h\r1 m9ute1 & second :5 ! circuit 0 clos$4 ,! second electro-magnet causes a po9t] to make a m>k on ! pap] receiv+ ! record ( ! motion4 ,?is m>k indicates ! "p ( ! e>?quake at :i* ! circuit 0 clos$4 ,illu/ration3 ,,fig4 #h4 ,! duration ( ! e>?quake is e/imat$ f ! l5g? ( ! record on ! smok$ pap] & ! rate ( motion ( ! drum4 ,! nature & p]iod ( ! diff]5t movem5ts are obta9$ f ! curves drawn on ! pap]4 ,mr4 ,gray has s9ce greatly modifi$ ?is app>atus1 notably by ! introduction ( a b& ( pap] suffici5tly long to take a record = tw5ty-f\r h\rs )\t repetition4 ,! record is writt5 9 ink by means ( f9e siphons4 ,9 ?is way ! in/rum5t1 :i* is extremely s5sitive to *ange ( level1 c be made to %[ n only e>?quakes1 b ! pulsations ( long p]iod :i* h rec5tly occupi$ s mu* att5tion4 ,,*apt] ,,iii4 ,,e>?quake ,,motion ,,discuss$ ,,!oretically4 ,ideas ( ! anci5ts 7! views ( ,travag9i1 ,hooke1 ,woodw>d1 ,/ukeley1 ,mit*ell1 ,"y1 ,mallet7--,nature ( ela/ic waves & vibrations--,possible causes ( di/urbance 9 ! ,e>?'s cru/--,! "t ( vibration ( an e>? p>ticle--,velocity & accel]ation ( a p>ticle--,propagation ( a di/urbance z det]m9$ by exp]im5ts ^u ! ela/ic moduli ( rocks--,! int5sity ( an e>?quake--,area ( greate/ ov]turn+ mom5t--,e>?quake waves--,reflexion1 refraction1 & int]f]5ce ( waves--,radiation ( a di/urbance4 ,ideas ( ,e>ly ,writ]s4--,"o ( ! fir/ acc\nts ( ! v>ieties ( motion :i* may be exp]i5c$ at ! "t ( an e>?quake is to be f\nd 9 ! classification ( e>?quakes giv5 by ,ari/otle4#h ,x is z foll[s3-- #a4 ,epicl9t1 or e>?quakes :i* move ! gr\nd obliquely4 #b4 ,bra/1 ) an upw>d v]tical motion l boil+ wat]4 #c4 ,*asmati1 :i* cause ! gr\nd to s9k & =m holl[s4 #d4 ,rhect1 :i* raise ! gr\nd & make fissures4 #e4 ,o/1 :i* ov]?r[ ) "o ?ru/4 #f4 ,palmati1 :i* %ake f side to side ) a sort ( tremor4 ,f ! six? gr\p 9 ?is classification we see t ?is e>ly writ] did n reg>d e>?quakes z necess>ily isolat$ ev5ts1 b t "s ( !m consi/$ ( a succession ( backw>d & =w>d vibratory motions4 ,he also di/+ui%es betwe5 ! total duration ( an e>?quake & ! l5g? (1 & int]vals betwe51 a s]ies ( %ocks4 ,ari/otle _h1 9 fact1 "s idea ( :at mod]n writ]s ^u ord9>y e>?quakes w\ld t]m #8modality4' ,! e>lie/ writ] :o _h ! idea t an e>?quake 0 a pulse-l motion propagat$ ?r\gh solid gr\nd appe>s to h be5 ,francisci ,travag9i1 :o1 9 #afgi1 wrote ^u an e>?quake :i* 9 #affg _h ov]?r[n ,ragusa4 ,! me?od 9 :i* ! pulses 7 propagat$ he illu/rat$ by exp]im5ts4 ,hooke1 :o1 9 #afij1 deliv]$ disc\rses on e>?quakes be=e ! ,royal ,society1 divides ^! ph5om5a accord+ to ! geological effects !y h produc$2 ?us !re is a g5us produc+ elevations1 a g5us produc+ s9k+s1 a g5us produc+ conv]sions & transportations1 & a g5us :i* produces :at1 9 mod]n language1 we %\ld t]m metamorphic action4 ,woodw>d1 9 8 #8,natural ,hi/ory1' writt5 9 #afie1 speaks ( e>?quakes z be+ agitations & concussions produc$ by wat] 9 ! int]ior ( ! e>? com+ 9 contact ) int]nal fires4 ,/ukeley obs]v$ t an e>?quake 0 #8a tremor ( ! e>?1' to be expla9$ z a vibration 9 a solid4 ,! ,rev4 ,john ,mit*ell1 writ+ 9 #agfj1 says t ! motion ( ! e>? 9 e>?quakes is p>tly tremul\s & p>tly propagat$ by waves4 ,f ^! few examples1 to :i* might be add$ _m m1 x w be se5 t an e>?quake di/urbance has usually be5 reg>d$ z a concussion1 vibration1 trembl+1 or undulatory movem5t4 ,fur!r1 x c be se5 9 n>ratives ( e>?quakes t x _h be5 (t5 obs]v$ t ^! trembl+s & %ak+s cont9u$ ov] a c]ta9 p]iod ( "t4 ,al?\gh x _h be5 notic$ t l>ge areas 7 almo/ simultane\sly affect$ by ^! di/urbances1 no def9ite idea appe>s to h exi/$ z to h[ e>?quake motion 0 propagat$4 ,usually x 0 assum$ t ! di/urbance spread ?r\gh subt]ranean *annels4 ,! fir/ true conception ( e>?quake motion & ! mann] ( its propagation is due to ,dr4 ,?omas ,"y1 :o sugge/$ t e>?quake motion 0 vibratory1 & x might be #8propagat$ ?r\gh ! e>? ne>ly 9 ! same mann] z a noise is convey$ ?r\gh ! air4' ,! same idea 0 m\ld$ into a m def9ite =m by ,gay ,lussac4 ,! fir/ accurate def9ition ( an e>?quake is due to ,mr4 ,rob]t ,mallet1 :o1 aft] collect+ & exam9+ _m facts connect$ ) e>?quake ph5om5a1 & reason+ on ^!1 ) ! help ( kn[n laws connect$ ) ! production & propagation ( waves ( v>i\s descriptions1 =mulat$ 8 views z foll[s3-- ,an e>?quake is #8! transit ( a wave or waves ( ela/ic compression 9 any direction f v]tically upw>ds to horizontally1 9 any azimu?1 ?r\gh ! cru/ & surface ( ! e>?1 f any c5tre ( impulse or f m ?an "o1 & :i* may be att5d$ ) s\nd & tidal waves1 dep5d5t ^u ! impulse & ^u circum/ances ( position z to sea & l&4' ,9 brief1 s f> z motion 9 ! e>? is conc]n$4 ,mallet def9$ an e>?quake z be+ a motion due to ! transit ( waves ( ela/ic compression4 ,9 _m cases x is possible t ?is is /rictly true1 b 9 succe$+ pages x w be %[n t e>?quake motion may also be due to ! transit ( waves ( ela/ic di/ortion4 ,to obta9 a true idea ( e>?quake motion is a matt] ( c>d9al importance1 z x =ms ! key-/one ( _m inve/igations4 ,if we "k ! nature ( ! motion produc$ by an e>?quake1 we are aid$ 9 track+ x to its orig91 & 9 reason+ z to h[ x 0 produc$4 ,if our k ( ! nature ( ! motion ( an e>?quake is incorrect1 x w be impossible = u intellig5tly to con/ruct build+s to )/& ! effects ( ^! di/urbances4 ,we h ?us to consid]1 9 ?is portion ( seismology1 a po9t ( great sci5tific importance1 & %all deal ) x at "s l5g?4 ,nature ( ,ela/ic ,waves & ,vibrations4--,:5 x is /at$ t an e>?quake consi/s ( ela/ic waves ( compression & di/ortion1 ! /ud5t ( physics has a cle> idea ( :at is meant & a k ( ! me*anical laws :i* gov]n su* di/urbances4 ,! ord9>y read]1 h[ev]1 & ! majority ( ! inhabitants ( e>?quake c\ntries1 :o ( all p h ! greate/ int]e/ 9 ?is matt]1 may n h s cle> a conception1 & x w1 !re=e1 n be out ( place to give "s g5]al explanation on ?is po9t4 ,! ord9>y idea ( a wave is t x is a di/urbance simil> to t :i* we (t5 see 9 wat]4 ,waves l ^! mu/ n1 h[ev]1 be conf\nd$ ) ela/ic waves4 ,a di/urbance produc$ 9 wat]1 say1 = in/ance1 by dropp+ a /one into a pond1 is propagat$ outw>ds by ! action ( gravity4 ,fir/1 a ridge ( wat] is rais$ up by ! /one pass+ b5ea? ! surface4 ,z ?is ridge falls t[>ds its normal position 9 virtue ( its weight1 x raises a second ridge4 ,?is second ridge raises a ?ird ridge1 & s on4 ,! wat] moves v]tically up & d[n1 :il/ ! wave itself is propagat$ horizontally4 ,to und]/& :at is meant by ela/ic waves1 x is fir/ necess>y to und]/& :at is meant by ! t]m ela/ic4 ,9 popul> language ! t]m ela/ic is conf9$ to sub/ances l india-rubb]1 & b seldom to rock-l mat]ials1 ?r\gh :i* e>?quake waves are propagat$4 ,india-rubb] is call$ ela/ic because aft] we remove a compressive =ce x has a t5d5cy to spr+ back to its orig9al %ape4 ,! ela/ic =ce ( ! india-rubb] is 9 ?is case ! =ce :i* causes x to resi/ a *ange ( =m4 ,n[1 a piece ( rock may1 up to a c]ta9 po9t1 l ! india-rubb]1 be compress$1 & :5 ! compress+ =ce is remov$ x w also t5d to resume its orig9al =m4 ,h[ev]1 z ! rock (f]s m resi/ance to ! compress+ =ce ?an ! india-rubb] (f]s1 we say t x is ! m ela/ic4 ,x may be "h obs]v$ t a sub/ance l granite (f]s great resi/ance1 n only to compression or a *ange ( volume1 b also to a *ange ( =m or %ape2 :]eas a sub/ance l air1 :i* is also ela/ic1 only (f]s resi/ance to compression1 b n to a *ange ( %ape4 ,) ^! ideas be=e u we w n[ proce$ to consid] h[1 aft] a body has be5 sudd5ly compress$ or di/ort$1 ?is di/urbance is propagat$ ?r\gh ! mass4 ,= ! ela/ic body let u take a long spiral spr+ hung f ! ceil+ ( a room & kept slightly /ret*$ by a weight4 ,if we give ?is weight an upw>d tap f bel[1 say ) a hamm]1 we %all obs]ve a pulse-l wave :i* runs up ! spr+ until x rea*es ! ceil+ ( ! room4 ,"h x w1 s to speak1 reb\nd1 l a billi>d ball f ! end ( a table1 & run t[>ds ! weight f :i* x />t$4 ,:il/ ?is is go+ on we may also obs]ve t ! weight is mov+ up & d[n4 ,"h1 !n1 we h two di/9ct ?+s to obs]ve--"o be+ ! transmission ( motion up to ! ceil+1 :i* we may lik5 to ! transmission ( an e>?quake wave betwe5 two di/ant localities on ! e>?'s surface1 & ! o!r be+ ! up & d[n motion ( our weight1 :i* we may comp>e to ! backw>d & =w>d sw++ :i* we exp]i5ce at ! "t ( an e>?quake4 ,^! two motions--namely1 ! pulse-l wave produc$ by ! transmission ( motion1 & ! backw>d & =w>d oscillation ( ! weight or ( any po9t on ! spr+--mu/ be c>efully di/+ui%$ f ea* o!r4 ,fir/1 we w consid] ! backw>d & =w>d motion ( ! weight4 ,! di/ance ?r\gh :i* ! weight moves dep5ds ^u ! =ce ( ! bl[4 ,! numb] ( up & d[n oscillations x makes1 say 9 a second1 dep5ds ^u ! /iffness ( ! spr+4 ,! weight1 suppos+ x to be always ! same1 w move m quickly at ! end ( a /iff spr+ ?an at ! end ( a flaccid "o2 t is to say1 its velocity is quick]4 ,z 9 any giv5 spr+ ! numb] ( up & d[n oscillations are always ! same 9 a giv5 int]val ( "t1 if ^! oscillations are ( great ext5t1 ! weight mu/ move m quickly ) l>ge ?an ) small oscillations4 ,at ! "t ( an e>?quake ! mann] 9 :i* we are mov$ backw>d & =w>d is v simil> to ! mann] 9 :i* ! weight is mov$4 ,if we /& on a h>d rock-l granite1 we are to a great ext5t plac$ z if we 7 atta*$ to a /iff quickly-vibrat+ spr+4 ,if1 h[ev]1 we are on a s(t rock1 x is m l be+ on a loose flaccid spr+4 ,all t has ?us f> be5 consid]$ has be5 a backw>d & =w>d k9d ( motion1 :]e !re is a rectil9e> compression & ext5sion among/ ! p>ticles on :i* we /&4 ,we might1 h[ev]1 imag9e our rock1 :i* = ! mom5t we w consid] to be a squ>e column1 to be twi/$1 & ?us h its %ape alt]$4 ,:5 ! twi/+ =ce is tak5 (f x seems evid5t t ! column w\ld endeav\r to untwi/ itself or rega9 its orig9al =m4 ,n[ ! =ce :i* a body (f]s aga9/ a *ange ( volume may be v diff]5t f t :i* x (f]s aga9/ a *ange ( =m4 ,9 di/urbances :i* take place 9 ! rocky cru/ ( our e>?1 x w\ld seem possible t we may h vibrations set up :i* are ei!r compressions & ext5sions or twi/+s & di/ortions4 ,^! may take place sep>ately or simultane\sly1 or we may h resultant motions due to _! comb9ation4 ,! foll[+ are examples ( possible causes :i* might give rise to ^! diff]5t ord]s ( di/urbance3-- #a4 ,imag9e a l>ge area /ret*$ by elevation until x rea*es ! limit ( its ela/icity & cracks4 ,aft] crack+1 9 consequ5ce ( its ela/icity1 x w fly back ov] ! :ole area l a brok5 spr+1 & ea* po9t 9 ! area w oscillate r\nd its new position ( equilibrium4 ,9 ?is case !re w be no waves ( di/ortion except+ ne> ! end ( ! crack1 :]e waves are transmitt$ 9 a direction p>allel to ! fissure4 #b4 ,! gr\nd is brok5 & slips ei!r up1 d[n1 or sideways1 z we see to h tak5 place 9 ! production ( faults4 ,"h we get di/ortion 9 ! direction ( ! movem5t1 & waves are produc$ by ! ela/ic =ce ( ! rock1 caus+ x to spr+ back f its di/ort$ =m4 ,9 a case l ?is ! production ( a fissure runn+ nor? & s\? might give rise to nor? & s\? vibrations1 :i* w\ld be propagat$ end on t[>ds ! nor? & s\?1 b broadside on t[>ds ! ea/ & we/4 ,) di/urbances ( ?is k9d1 on acc\nt ( ! want ( homog5e\sness 9 ! mat]ials 9 :i* !y are produc$1 we %\ld expect to f9d waves ( compression & ext5sion4 #c4 ,a truly sph]ical cavity is sudd5ly =m$ by ! explosion ( /eam 9 ! mid/ ( an ela/ic m$ium4 ,9 ?is case all ! waves w be ^? ( compression1 ea* p>ticle mov+ backw>d & =w>d along a radius4 ,%\ld ! cavity1 in/ead ( be+ truly sph]ical1 be irregul>1 x is evid5t t1 9 addition to ! normal vibration ( compression1 transv]se waves ( di/ortion w be m or less pron\nc$1 dep5d+ ^u ! nature ( ! cavity4 ,! comb9ation ( ^! two sets ( vibrations may cause a po9t 9 ! e>? to move 9 a circle1 an ellipse1 ! =m ( a figure eight1 & 9 o!r curves simil> to ^!1 :i* are produc$ by app>atus design$ to %[ ! comb9ation ( h>monic motion4 ,f ^! examples x w be se5 t we h !re=e to consid] two k9ds ( vibrations--"o produc$ by compression or ! alt]ation ( volume1 & ! o!r produc$ by an alt]ation 9 %ape4 ,n[ ! resi/ance :i* a body (f]s1 ei!r to a *ange 9 its volume or 9 its %ape1 is call$ its ela/icity1 & ! law :i* gov]ns ! backw>d & =w>d motion ( a p>ticle "u ! influ5ce ( ?is ela/icity may be express$ z foll[s3 ,if ,t be ! "t ( vibration1 or ! "t tak5 by a p>ticle to make "o complete backw>d & =w>d sw+1 ,d ! d5sity ( ! mat]ial ( :i* ?is p>ticle =ms a "p1 & ,e ! prop] modulus ( ela/icity ( ! mat]ial1 !n1 ,t #b ,d_/,e ,f ?is =mula1 ,t #b ,d_/,e1 we see t ! "t ( vibration ( ! e>? dur+ an e>?quake1 or ! rate at :i* we are %ak5 backw>ds & =w>ds1 v>ies directly z ! squ>e root ( ! d5sity ( ! mat]ial on :i* we /&1 & inv]sely z ! squ>e root ( a numb] proportional to its ela/icity4 ,velocity & ,accel]ation ( an ,e>? ,p>ticle4--,ano!r important po9t1 :i* ! practical seismologi/ has (t5 br\ght to 8 notice1 is ! "q ( ! velocity ) :i* an e>? p>ticle moves4 ,accord+ to ! =mula1 ,t #b ,d_/,e1 we %\ld expect t a p>ticle w\ld make ea* semi-vibration 9 an equal "t1 & f a k ( ! d5sity & ela/ic moduli ( a body ?is "t might be calculat$4 ,al?\gh ! "t ( a semi-oscillation may be con/ant1 we mu/ be> 9 m9d t1 l ! bob ( a p5dulum dur+ ea* ( its sw+s1 ! p>ticle />ts f re/1 increases 9 velocity until x rea*es ! middle portion ( its half sw+1 f :i* x gradually decreases 9 spe$ until x rea*es z]o1 :5 x aga9 comm5ces a simil> motion 9 ! opposite direction4 ,^! p5dulum-l vibrations are sometimes spok5 ( z simple h>monic motions4 ,if we "k ! di/ance ?r\gh :i* an e>?quake moves 9 mak+ a s+le sw+1 & ! "t tak5 9 mak+ ?is sw+1 on ! assumption t ! motion is simple h>monic we c easily calculate ! maximum velocity ) :i* ! p>ticle moves4 ,?us1 if an e>? p>ticle takes "o second to complete a semi-oscillation1 half ( :i*1 or ! amplitude ( ! motion1 equals a1 ! maximum velocity equals a4 ,aga91 assum+ ! e>? vibrations to be simple h>monic1 ! maximum accel]ation or rate ( *ange 9 velocity w come ab\t at ! ends ( ea* semi-oscillation2 & if ,v be ! maximum velocity ( ! p>ticle1 & a ! amplitude or half semi-oscillation1 !n ! ,v#b maximum accel]ation equals ------4 a ,lat] on x w be %[n1 z ! result ( exp]im5t1 t c]ta9 ( ! m important e>? oscillations 9 an e>?quake are n simple h>monic motion4 ,nev]!less ! above rem>ks w be ( assi/ance 9 %[+ h[ ! velocity & o!r elem5ts connect$ ) ! motion ( an e>? p>ticle1 :i* are requir$ by ! practical seismologi/1 may be calculat$1 irrespective ( assumptions z to ! nature ( ! motion4 ,propagation ( a ,di/urbance4--,we may next consid] ! mann] 9 :i* a di/urbance1 9 :i* !re are bo? vibrations ( compression & ( di/ortion1 is propagat$4 ,! fir/ or normal set ( vibrations are propagat$ 9 a mann] simil> to t 9 :i* s\nd vibrations are propagat$4 ,f a c5tre ( di/urbance ^! movem5ts approa* an obs]v] at a di/ant /ation1 s to speak1 end on4 ,! o!r vibrations h a direction ( motion simil> to t :i* we believe to exi/ 9 a ray ( light4 ,^! w\ld approa* ! obs]v] broadside on4 ,if ! di/urbance pass$ ?r\gh a =mation l a s]ies ( p]fectly lam9at$ slates1 ea* ( ^! two sets ( vibration might be subdivid$1 & we %\ld !n obta9 :at ,mallet has t]m$ ord9>y & extraord9>y normal & transv]se vibrations4 ,9 consequ5ce ( ! diff]5ce 9 ! ela/ic =ces on :i* ! propagation ( ^! two k9ds ( vibration dep5ds1 ! normal vibrations are transmitt$ fa/] ?an ! transv]sal ones--t is to say1 if an e>?quake orig9at$ f a bl[1 ! fir/ ?+ t w\ld be felt at a po9t di/ant f ! orig9 ( ! %ock w\ld be a backw>d & =w>d motion 9 ! direction to & f ! orig91 & !n1 a %ort int]val aft]w>ds1 a motion transv]sal1 or at "r angles to ?is1 w\ld be exp]i5c$4 ,f ! ma!matical !ory ( vibratory motions x is possible to calculate ! velocity ) :i* a di/urbance is propagat$4 ,z ! result ( ^! inve/igations x has be5 %[n t normal vibrations travel m quickly ?an transv]se vibrations4 ,d$uctions f exp]im5ts on small specim5s are1 h[ev]1 invalidat$ by ! fact t ! specim5s us$ = exp]im5ts are1 ( c\rse1 ne>ly homog5e\s1 :il/ ! e>?quake passes ?r\gh a mass :i* is het]og5e\s & m or less fissur$4 ,mallet1 by exp]im5ts #8on ! compressibility ( solid cubes ( ^! rocks1 obta9$ ! mean modulus ( ela/icity1' ) ! result t #8ne>ly sev5-eigh?s ( ! full velocity ( wave-transit due to ! mat]ial1 if solid & cont9u\s1 is lo/ by reason ( ! het]og5eity & discont9uity ( ! rocky masses z !y are f\nd pil$ toge!r 9 nature4' ,! full velocities ( wave-transit1 z calculat$ by ,mallet f a !orem giv5 by ,poisson1 7-- ,= slate & qu>tz transv]se to lam9ation1 #i1fia feet p] second4 9 l9e ( lam9ation1 #e1dae ,?is m rapid transmission 9 a direction transv]se to ! lam9ation1 ,mr4 ,mallet obs]ves1 may be m ?an c\nt]balanc$ by ! discont9uity ( ! mass transv]se to ! same direction4 ,! ,int5sity ( an ,e>?quake4--,! int5sity ( an e>?quake is be/ e/imat$ by ! int5sity ( ! =ces :i* are br\ght to be> on bodies plac$ on ! e>?'s surface4 ,^! =ces are evid5tly proportional to ! rate ( *ange ( velocity 9 ! body1 &1 z ! de/ructive effect w be proportional to ! maximum =ces1 we may consi/5tly indicate ! int5sity ( an e>?quake by giv+ ! maximum accel]ation to :i* bodies 7 subject dur+ ! di/urbance4 ,on ! assumption t ! motion ( a po9t on ! e>?'s surface is simple h>monic1 ! maximum accel]ation is directly z ! maximum velocity & inv]sely z ! amplitude ( v#b motion1 or z ---------- :]e v indicates velocity & a amplitude4 a ,! next "q ( importance is to det]m9e ! mann] 9 :i* e>?quake en]gy becomes dissipat$--t is1 to comp>e toge!r ! int5sity ( an e>?quake z record$ at two or m po9ts at diff]5t di/ances f ! orig94 ,fir/ let u imag9e ! orig9 ( our e>?quake to be surr\nd$ by conc5tric %ells1 ea* ( :i* is ! bread? ( ! vibration ( a p>ticle4 ,go+ outw>ds f ! c5tre1 ea* successive %ell w conta9 a great] numb] ( p>ticles1 ?is numb] increas+ directly z ! squ>e ( ! di/ance f ! orig94 ,let ! bl[ h its orig9 at ! c5tre1 & give a vibratory movem5t to ! p>ticles 9 "o ( ! %ells ne> ! c5tre4 ,?is %ell may be suppos$ to possess a c]ta9 am\nt ( en]gy1 :i* w be measur$ by its mass & ! squ>e ( ! velocity ( its p>ticles4 ,9 transf]r+ ?is en]gy to ! neighb\r+ %ell :i* surr\nds x1 because x has to set 9 motion a great] numb] ( p>ticles ?an x conta9s itself1 ! en]gy 9 any "o p>ticle ( ! second lay] w be less ?an ! en]gy 9 any "o p>ticle 9 ! fir/ lay]2 ! total en]gy 9 ! second %ell1 h[ev]1 w be equal to ! total en]gy 9 ! fir/ %ell4 ,neglect+ ! en]gy lo/ dur+ ! transf]1 if ! en]gy 9 a p>ticle ( ! fir/ %ell at any p>ticul> phase ( ! motion be ,k#a1 & ! en]gy 9 a p>ticle ( ! second %ell ,k#b1 ^! quantities are to ea* o!r inv]sely z ! masses ( ! %ells--t is1 inv]sely z ! squ>es ( ! mean radii ( ! %ells4 ,k#b r#ab ,9 symbols1 ---------- ------------------ 7#a7 ,k#a r#bb ,assum+ t en]gy is dissipat$1 ,k#b r#ab r#ab ---------- ------------------ f ------------------ 7#b7 ,k#a r#bb r#bb :]e f #a is ! rate ( dissipation ( en]gy :i* is assum$ to be con/ant4 ,area ( greate/ ,ov]turn+ ,mom5t4--,al?\gh ! rate ( dissipation ( ! impulsive effects ( an e>?quake may foll[ a law l t j enum]at$1 x mu/ be rememb]$ t if ! dep? ( ! orig9 is comp>able ) ! radius ( ! area :i* is %ak51 ! maximum impulsive effect z exhibit$ by ! actual de/ruction on ! surface may n be imm$iately above ! orig9 :]e build+s h simply be5 lift$ v]tically up & d[n1 b at "s di/ance f ?is po9t1 :]e ! impulsive ef=t has be5 m oblique4 ,at ! epic5trum we h ! maximum ( ! true int5sity z measur$ by ! accel]ation ( a p>ticle1 or ! height to :i* a body might be project$1 b x w be at "s di/ance f ?is :]e we %all h ! maximum int5sity z exhibit$ by an ov]turn+ ef=t4 ,?is w be r5d]$ cle> by ! foll[+ diagram4 ,9 ! accompany+ diagram let ,o be ! orig9 ( a %ock1 & ,o ,c ! seismic v]tical equal to r4 ,let ! direct or normal %ock em]ge at ,c1 ,c#a1 ,c#b1 & at ! angles #a1 #b1 c4 ,assum+ t ! displacem5t ( an e>? p>ticle at ,c equals ,c ,b1 & at ,c#a equals c#a b#a1 & at ,c#b equals c#b b#b1 c41 & let ^! displacem5ts ,c ,b1 c#a b#a1 c#b b#b1 c41 = ! sake ( argum5t1 v>y inv]sely z r1 r#a1 r#b1 c4 ,illu/ration3 ,,fig4 #i4 ,! "q is to det]m9e :]e ! horizontal compon5t ,c ,a ( ^! normal motions is a maximum4 ,fir/ obs]ve t ! triangle ,o ,c c is simil> to a1 b1 c4 h ,also r ----------1 & !re=e ! normal compon5t c#a s9 s9 b#a at ,c#a is equal to ,c ----------4 h ,also c#a a#a c#a b#a1 cos 4 s9 cos c s9 #b ,c#a a ,c ------------------------ -------- --------------1 h h #b & s9 #b is greate/ :5 #b #ij or #de4 ,t is to say1 ! horizontal compon5t rea*es a maximum :]e ! angle ( em]g5ce equals #de4 ,?is "q has be5 discuss$ on ! assumption t ! amplitude ( an e>? p>ticle v>ies inv]sely z its di/ance f ! orig9 ( ! %ock4 ,%\ld we1 h[ev]1 assume t ?is amplitude v>ies inv]sely z ! squ>e ( ! di/ance f ! orig91 we are l$ to ! result t ! area ( greate/ di/urbance is ne>] to ! po9t :]e ! angle ( em]g5ce is #ee #dd #i4 ,bo? ( ^! me?ods are ref]r$ to by ,mallet1 b ! fir/ is consid]$ z probably ! m correct4 ,e>?quake ,waves4--,hi!rto we h *iefly consid]$ e>?quake vibrations2 n[ we w say a few words ab\t e>?quake waves4 ,if we /rike a long iron rod at "o end1 we c imag9e t1 z 9 ! long spr+1 a pulse-l motion is transmitt$4 ,if ! rod be /ruck quickly1 ! pulses w rapidly succe$ ea* o!r1 & if /ruck sl[ly ! pulses w be at long] int]vals4 ,ea* individual pulse1 h[ev]1 w travel along ! rod at ! same rate1 & h5ce ! di/ance betwe5 any two w rema9 con/ant2 b t di/ance w dep5d on ! int]val betwe5 ! bl[s produc+ ^! pulses be+ equal to ! di/ance travell$ by "o pulse be=e ! next bl[ is /ruck4 ,f ?is we see t an irregul> di/urbance w produce an irregul> succession ( motions2 "s w be l long undulations 9 a wide deep ocean1 :il/ o!rs w be l ripples 9 a %all[ bay4 ,aga91 consid] ! b> to be /ruck "o bl[ only1 & !n left to itself4 ,! b> w propagate a s]ies ( pulses along its l5g?1 due to ! out & 9 vibration ( its end4 ,^! w succe$ ea* o!r at regul> int]vals1 & w be mix$ up ) ! pulses we h previ\sly consid]$4 ,f ?is we see t 9 an e>?quake1 if x be produc$ by "o bl[1 ! motion w be iso*ron\s 9 its "*2 b if x be due to a succession ( bl[s at regul> int]vals1 ! motion w be ! resultant ( a s]ies ( iso*ron\s motions1 & w be p]iodical4 ,if ! impulses are irregul>1 y h a motion :i* is ! resultant ( a numb] ( iso*ron\s motions due to ea* impulse1 b ^! comp\nd$ toge!r 9 a diff]5t mann] at ea* in/ant dur+ ! e>?quake1 & giv+ z a result a motion :i* is 9 no s5se iso*ron\s4 ,?is approa*es m ne>ly to ! actual motions we feel z e>?quakes4 ,if we c imag9e ! gr\nd %ak5 by an e>?quake1 made ( a transp>5t mat]ial :i* transmitt$ less light :5 compress$1 & we c\ld look d[n ^u a long ext5t ( ?is at ! "t ( an e>?quake1 we %\ld see a s]ies ( d>k b&s indicat+ /rips ( c\ntry :i* 7 compress$4 ,! di/ances betwe5 ^! b&s might be irregul>4 ,keep+ our att5tion on "o p>ticul> b&1 ?is w\ld be se5 to travel =w>d 9 a direction f ! s\rce4 ,if we kept our eye on "o p>ticul> po9t1 x w\ld appe> to op5 & %ut1 becom+ light & d>k alt]nately4 ,z to ! exi/5ce ( ^! ela/ic waves 9 actual e>?quakes we h no direct exp]im5tal evid5ce4 ,! only k9d ( wave ) :i* we are famili> is a true surface undulation1 :i*1 al?\gh hav+ ! appe>ance ( a wat]-wave1 may nev]!less repres5t a di/rict ( compression4 ,,*apt] ,,iv4 ,,e>?quake ,,motion ,,z ,,d$uc$ ,,f ,,exp]im5t4 ,exp]im5ts ) fall+ weights--,exp]im5ts ) explosives--,results obta9$ f exp]im5ts--,relative motion ( two adjac5t po9ts--,! effect ( hills & excavations ^u ! propagation ( vibrations--,! int5sity ( artificial di/urbances--,velocity ) :i* e>? vibrations are propagat$--,exp]im5ts ( ,mallet--,exp]im5ts ( ,abbot--,exp]im5ts 9 ,japan--,mallet's results--,abbot's results--,results obta9$ 9 ,japan4 ,exp]im5ts ) ,fall+ ,weights4--,a s]ies ( exp]im5ts1 z ! nature ( ! di/urbance produc$ 9 ! surface ( ! e>? :5 a heavy weight is all[$ to fall on x1 0 begun 9 ,novemb] #ahhj by ,mr4 ,t4 ,gray & ! au?or4 ,^! exp]im5ts 7 c>ri$ out at ! ,akabane ,eng9e]+ ,works 9 ,tokio4 ,! weight us$ 0 a ball ( iron weigh+ ab\t a ton1 :i* 9 ! diff]5t exp]im5ts 0 all[$ to fall f heights v>y+ betwe5 t5 & ?irty-five feet4 ,! position ( ! place :]e ! ball 0 all[$ to fall 0 su* t 9 "o direction ! vibrations 7 transmitt$ up ! side ( a /eep hill1 9 ano!r direction across a pond ) p]p5dicul> sides1 & 9 ano!r direction across a level pla9 ! mat]ial ( :i* consi/$ = ! mo/ "p ( h>d5$ mud ext5d+ to a v consid]able dep?4 ,! vibrations produc$ by ! fall ( ! ball 7 transmitt$ ?r\gh ?is h>d mud ) consid]able int5sity to a di/ance ( betwe5 #cjj & #djj feet4 ,! object ( ! exp]im5t 0 to f9d ! nature ( ! vibrations produc$ 9 ! cru/ ( ! e>? by su* a bl[1 ! velocity ( transmission ?r\gh ?is comp>atively s(t mat]ial1 ! effect ( hills & excavations 9 cutt+ (f su* di/urbances1 & ! law accord+ to :i* ! amplitude ( ! vibrations dim9i%es ) ! di/ance f ! s\rce4 ,a consid]able v>iety ( app>atus 0 us$ dur+ ^! exp]im5ts1 b ! mo/ reliable results 7 obta9$ f ! records ( a roll+ sph]e seismograph1 :i* wrote ! vibrations on a /ation>y plate1 & f ! records ( two bracket seismographs1 simil> to ,pr(essor ,ew+'s horizontal lev] seismographs1 :i* gave a record ( ! vibrations z two rectangul> compon5ts on a mov+ plate ( smok$ glass4 ,illu/ration3 ,,fig4 #aj4 ,! g5]al result z to ! nature ( ! di/urbance 0 t two di/9ct sets ( vibrations 7 set up by ! bl[4 ,9 "o set ! direction ( motion 0 along a l9e jo9+ ! po9t ( obs]vation ) ! po9t f :i* ! di/urbance emanat$2 9 ! o!r set ! direction ( motion 0 at "r angles to t l9e4 ,! nature ( ! resultant motion w be ga!r$ f fig4 #aj1 :i* is tak5 f ! records drawn by ! roll+ sph]e seismograph at a di/ance ( #ej feet1 #ajj feet1 & #bjj feet respectively f ! po9t :]e ! ball /ruck ! gr\nd4 ,! direct or normal vibrations rea*$ ! in/rum5t fir/1 & 7 foll[$ at an int]val dep5d+ on ! di/ance ( ! in/rum5t f ! orig9 by ! transv]se vibrations4 ,f ! records ( ^! two sets ( vibrations z sep>at$ by ! bracket seismographs1 comb9$ ) ! kn[n rate ( motion ( ! glass plate1 ! velocity ( transmission 0 f\nd to be1 = normal vibrations #ddf-dch feet p] second1 & = transv]se vibrations #ceg-cec feet p] second4 ,! effect ( ! hill 9 cutt+ (f ! di/urbance seem$ to be slight1 b ! direction ( ! vibrations :i* asc5d$ ! side 0 mo/ly transv]se4 ,! pond1 on ! o!r h&1 seem$ completely to cut (f ! di/urbance1 :i*1 h[ev]1 gradually crept r\nd ! side1 s t only a comp>atively small triangul> area 0 9 %ad[4 ,! amplitude ( ! vibrations dim9i%$ directly z ! di/ance increas$ = "s di/ance f ! orig91 b at great] di/ance ! rate ( dim9ution seem$ to be sl[]4 ,! transv]se vibration seem$ to die out less quickly ?an ! normal vibrations4#i ,^! exp]im5ts 7 aft]w>ds v consid]ably ext5d$ by ! au?or4 ,9 ^! lat] exp]im5ts *>ges ( f "o to two p\nds ( dynamite 7 plac$ 9 bore-holes ( v>i\s dep?s & explod$ by means ( electricity4 ,! results obta9$ confirm$ ! conclusions already arriv$ at f ! =m] exp]im5ts4 ,! exp]im5ts on velocity1 h[ev]1 seem$ to indicate t ! high] ! initial impulse ! great] 0 ! velocity4 ,! velocity ( propagation ( ! transv]se vibrations seem$ to approa* m & m to t ( ! direct$ vibrations z ! di/ance f ! orig9 ( di/urbance increas$4 ,fig4 #aa %[s ! nature ( ! record obta9$ f ! explosion ( two p\nds ( dynamite at ! bottom ( a bore-hole eight feet deep4 ,^! records %[ ! int]val ( "t :i* elaps$ betwe5 ! arrival ( ! normal & ! transv]se vibrations at po9ts di/ant #ajj1 #bej1 & #djj feet f ! bore-hole4 ,9 ! case ( ! #ajj-;feet /ation x w be obs]v$ t ! motion t[>ds ! orig9 is great] ?an t f ! orig94 ,x is also to be notic$ t ! p]iod ( vibration becomes great] z ! di/ance f ! orig9 increases4 ,illu/ration3 ,,fig4 #aa4--,records obta9$ at ?ree /ations ( ! motion ( ! gr\nd produc$ by ! explosion ( #b lbs4 ( dynamite4 ,! ,int5sity ( ,artificial ,di/urbances4--,! data :i* we h at our disposal = det]m9+ ! int5sity ( an e>? p>ticle :i* has be5 caus$ to vibrate by ! explosion ( a *>ge ( dynamite are a s]ies ( records simil> to t giv5 on p4 #fj4 ,^! di/urbances are practically surface movem5ts1 & may be comp>$ ) ! movem5ts ( an e>?quake :i* spreads ov] an area ! radius ( :i* is great z comp>$ ) its dep?4 ,to f9d ! mean accel]ation ( an e>? p>ticle1 :i* quantity has be5 tak5 to repres5t int5sity1 dur+ any simple backw>d or =w>d motion ( ! e>?1 x w be fir/ necess>y to det]m9e ! amplitude ( ?is motion & its maximum velocity1 ! mean ,v#b accel]ation be+ equal to ------4 #b;,a ,illu/ration3 ,,fig4 #ab4 ,! second & ?ird movem5ts 9 a %ock inv>iably exhibit$ ! greate/ int5sity1 & to a di/ance ( #djj feet f ! orig91 :]e ab\t ?ree p\nds ( dynamite _h be5 explod$ 9 a bore-hole ab\t six feet deep1 ^! int5sities decreas$ directly z ! di/ance f ! orig94 ,! less int5se movem5ts also decreas$ directly z ! di/ance f ! orig9 to a c]ta9 po9t1 b aft] t !y decreas$ m sl[ly4 ,a mean result ( ! m prom95t vibrations 9 f\r sets ( exp]im5ts is %[n 9 ! curve1 fig4 #ab1 :]e ! horizontal measurem5ts repres5t di/ance f ! orig9 9 feet1 & ! v]tical measurem5ts mean accel]ation 9 ?\s&s ( millimetres p] second4 ,?is curve approximates to an equi-angul> hyp]bola4 ,! area betwe5 ! curve & its asymptotes is proportional to ! :ole en]gy ( ! %ock4 ,! area ( ! diagram is proportional to ! en]gy giv5 up to ! gr\nd by ! explosion ( ?ree p\nds ( dynamite4 ,if we call ! unit %ock ! effect produc$ by ! explosion ( "o p\nd ( dynamite1 ! above artificial e>?quake _h an int5sity equal to ?ree4 ,! only o!r inve/igations :i* h be5 made 9 ?is int]e/+ bran* ( obs]vational seismology are ^? by ,mr4 ,rob]t ,mallet1#aj & ^? by ,g5]al ,h5ry ,l4 ,abbot4#aa ,mallet's ,results4--,! velocity ) :i* e>? vibrations 7 transmitt$ z d$uc$ by ,mr4 ,mallet 7 z foll[s3-- ,feet p] second ,9 s& #hbdiae ,9 contort$ /ratifi$ rock1 qu>tz1 & slate at ,holyhead #a1jhhffi ,9 discont9u\s & mu* %att]$ granite #a1cjfdbe ,9 m solid granite #a1ffdegd ,a /rik+ result :i* 0 obta9$ by ,mallet 9 8 exp]im5ts at ,holyhead 0 t ! transit velocity increases ) an increase 9 ! int5sity ( ! initial %ock4 ,?us ) a *>ge ( #ab1jjj p\nds ( p[d] ! transit rate 0 #a1cgc feet p] second1 :il/ ) #b1ajj p\nds ! transit rate 0 #a1jii feet p] second4 ,9 ^! exp]im5ts tremors 7 obs]v$ z prec$+ & foll[+ ! ma9 %ock4 ,abbot's ,results4--,! important results obta9$ by ,g5]al ,abbot are conta9$ 9 ! foll[+ table3-- ,a4 ,no4 ( ,obs]vation ,b4 ,di/ance to ,/ation 9 miles ,c4 ,type ( ,seismomet] ,d4 ,velocity 9 feet p] second ---------------------------------------- ---------------------- ,a ,date ,cause ( ,%ock ,b ,c ,d ---------------------------------------- ---------------------- #a ,aug4 #ah1 #ahgf #bjj lbs4 ( dynamite #e ,b #e1bhj #b ,sept4 #bd1 #ahgf ,hallet's ,po9t ,explosion #eacd ,a #c1hgc #c #hccj ,b #h1cjj #d #iccc ,a #d1eba #e #abgfi ,b #e1cji #f ,oct4 #aj1 #ahgf #gj lbs4 dynamite #acfj ,a #a1bdj #g ,sept4 #f1 #ahgg #djj #aafi ,a #c1dbh #h #aafi ,b #h1had #i ,sept4 #ab1 #ahgg #bjj #acdj ,a #f1gcj #aj #acdj ,b #h1gcj #aa #gj #acdj ,a #e1eei #ab #acdj ,b #h1dae ---------------------------------------- ---------------------- ,a seismomet] ( type ,a means t ! telescope us$ 9 obs]v+ ! tremor produc$ on ! surface ( a vessel ( m]cury by ! passage ( ! %ock _h a magnification ( #f1 :il/ a telescope ( ! type ,b _h a magnification ( #ab4 ,! mean velocity giv5 by six obs]vations ) type ,a is #d1bbe feet p] second1 :ile t giv5 by ! same numb] ) type ,b is #g1dge feet p] second4 ,illu/ration3 ,,fig4 #ac4 ,if we assume t ! fir/ tremor obs]v$ 9 ! m]cury is to det]m9e ! true rate ( transmission1 ,g5]al ,abbot tells u t we mu/ reject all obs]vations made ) type ,a1 inasmu* z !y d n reveal ! velocity ( ! lead+ tremor4 ,h[ev]1 he also tells u t a /ill high] p[] above #ab might h detect$ /ill e>li] tremors4 ,:5 gunp[d] 0 ! explosive1 ! obs]v]s not$ t ! di/urbance obs]v$ 9 ! m]cury took a mu* long] "t to rea* a maximum ?an x did :5 dynamite 0 employ$4 ,x 0 also obs]v$ t explosions fir$ b5ea? deep wat] gave a high] velocity ?an simil> explosions :i* took place b5ea? %all[ wat]4 ,9 ! latt] case mu* ( ! en]gy 0 probably exp5d$ 9 ?r[+ a jet ( wat] into ! air4 ,ano!r po9t :i* 0 obs]v$ appe>s to h be5 t ! rate v>i$ ) ! initial %ock4 ,?us3-- ,feet p] second #djj lbs4 ( dynamite gave #h1had #bjj #h1gcj #gj p[d] 7deep7 gave #h1dae ,also x is probable t ! rate ( a wave dim9i%$ ) its advance4 ,=1 ,feet p] second #bjj lbs4 ( dynamite gave = #a mile #h1gcj #e miles #e1bej #ej1jjj #h #h1cjj #ac #e1cjj ,g5]al ,abbot's g5]al conclusions are3-- #a4 ,a high magnify+ p[] ( telescope is ess5tial 9 seismometric obs]vations4 #b4 ,! m viol5t ! initial %ock ! high] is ! velocity ( transmission4 #c4 ,?is velocity dim9i%es z ! g5]al wave advances4 #d4 ,! movem5ts ( ! e>?'s cru/ are complex1 consi/+ ( _m %ort waves fir/1 increas+ & !n decreas+ 9 amplitude2 & ) a detonat+ explosive ! int]val betwe5 ! fir/ wave & ! maximum wave1 at any /ation1 is %ort] ?an ) a sl[ burn+ explosive4 ,results obta9$ 9 ,japan4--,f "s exp]im5ts made by ! au?or 9 ! gr\nds ( ! ,meteorological ,dep>tm5t 9 ,tokio1 ! foll[+ results 7 obta9$3-- ,a4 ,velocity 9 feet p] second = ! fir/ #bjj ft4 7,a to ,b7 ,b4 ,velocity 9 feet p] second = ! second #bjj ft4 7,b to ,c7 ,c4 ,velocity 9 feet p] second = #djj ft4 7,a to ,c7 ,d4 ,numb] ( ,c>tridges ( ,dynamite 7#f #a lb47 ---------------------------------------- - ,no4 ( ,explosion ,a ,b ,c ,d ---------------------------------------- - ,i4 #dfd #ahf #bfe #hc ,v]tical ,,iii4 -- #baa -- #aja vibrations ,,iv4 #ceb #bcd #bha #ga ,v4 #cdc #bcb #bgg #ej ,normal ,,vi4 -- -- #djg #ajj vibrations ,,vii4 -- -- #eaf #abe ,transv]se ,,viii4 -- -- #cdd #abe vibrations ---------------------------------------- - ,! g5]al results to be d$uc$ f ! above appe> to be3-- #a4 ,= v]tical motion4 7a7 ,= ! fir/ #bjj feet4 ,! velocity dep5ds ^u ! initial =ce--! great] ! *>ge ( dynamite ! great] ! velocity4 7b7 ,= ! second #bjj feet4 ,! above law only appe>s 9 exp]im5ts ,,iv4 & ,v41 b x mu/ be rememb]$ t ! orig9s ( ,i4 & ,,iii4 7 f>!r remov$ f ,a ?an ,,iv4 & ,v4 ,! spe$ ( ! wave dur+ ! second #bjj feet is always less ?an dur+ ! fir/ #bjj feet4 #b4 ,= normal vibrations4 ,"h ! spe$ betwe5 ,a & ,c is all t 0 measur$1 b we aga9 see t ! great] ! initial =ce1 or ! ne>] we are to ! orig9 ( ! di/urbance1 ! great] is ! velocity4 ,?is velocity is great] ?an ! velocity ( ! v]tical or transv]se vibrations4 #c4 ,= transv]se vibrations4 ,if we assume t ! v]tical vibrations are a compon5t ( ! transv]se motions we see ! same law z be=e--namely1 t ! ne>] we are to ! orig9 ( ! di/urbance ! great] is ! spe$ ) :i* t di/urbance is propagat$4 ,x w be obs]v$ t ! *ief law "h enunciat$ respect+ ! decrease 9 spe$ ( e>? vibrations is ! same z t po9t$ out by ,g5]al ,abbot1 f :i* x only diff]s by its be+ 9 all cases prov$ )\t ! introduction ( p]sonal errors1 = ! same explosion1 along ! same l9e ( gr\nd & = diff]5t k9ds ( vibrations4 ,,*apt] ,v4 ,,e>?quake ,,motion ,,z ,,d$uc$ ,,f ,,obs]vation ,,on ,,e>?quakes4 ,result ( feel+s--,! direction ( motion--,in/rum5ts z indicators ( direction--,duration ( an e>?quake--,p]iod ( vibration--,! amplitude ( e>? movem5ts--,side ( greate/ motion--,int5sity ( e>?quakes--,velocity & accel]ation ( an e>? p>ticle--,absolute int5sity ( an e>?quake--,radiation ( an e>?quake--,velocity ( propagation4 ,result ( ,feel+s4--,z ! result ( our exp]i5ces1 & by obs]vations ^u ! movem5ts produc$ 9 v>i\s bodies1 we c say t an ord9>y e>?quake consi/s ( a numb] ( backw>d & =w>d motions ( ! gr\nd foll[+ ea* o!r 9 quick succession4 ,sometimes ^! comm5ce & die out s g5tly t ^? :o h endeav\r$ to "t ! duration ( an e>?quake h f\nd x difficult to say :5 ! %ock comm5c$ & :5 x end$4 ,?is 0 a difficulty :i* ,mr4 ,james ,bissett 9 ,yokohama1 & ! au?or 9 ,tokio1 _h to cont5d aga9/ :51 9 #ahgh1 !y comm5c$ to "t %ocks betwe5 ^! two places4 ,sometimes ^! motions gradually increase to a maximum & !n die out z gradually z !y comm5c$4 ,sometimes ! maximum comes sudd5ly1 & at o!r times dur+ an e>?quake our feel+s di/9ctly tell u t !re are sev]al maxima4 ,^! h be5 ! exp]i5ces ( _m obs]v]s1 & h be5 record$ by writ]s s9ce ! e>lie/ times4 ,mallet devotes a *apt] to a consid]ation ( ! tremul\s motion t prec$es & foll[s a %ock1 & he tells u t a s+le %ock is an absolute impossibility4 ,9 speak+ ( e>?quakes1 he says3 #8,! almo/ univ]sal succession ( ph5om5a record$ 9 e>?quakes is1 fir/ a trembl+1 !n a sev]e %ock1 or sev]al 9 quick succession1 & !n a trembl+ gradually b rapidly becom+ ins5sible4' ,a quantitative & exact k ( ! nature ( e>?quake motion has only be5 atta9$ ( late ye>s4 ,! *ief results :i* inve/igators h aim$ at h be5 ! measurem5t ( ! amplitude1 ! p]iod1 ! direction1 & ! duration ( ! motions :i* con/itute an e>?quake4 ,att5tion has also be5 giv5 to ! velocity ) :i* a di/urbance is propagat$4 ,! ,direction ( ,motion4--,"o ( ! mo/ ord9>y obs]vations :i* are made ab\t an e>?quake is its direction4 ,if we 7 to ask ! inhabitants ( a t[n :i* _h be5 %ak5 by an e>?quake ! direction ( ! motion !y exp]i5c$1 x is n unlikely t _! replies w\ld include all ! po9ts ( ! compass4 ,_m1 9 consequ5ce ( _! al>m1 h n be5 able to make accurate obs]vations4 ,o!rs h be5 deceiv$ by ! motion ( ! build+ 9 :i* !y 7 situat$4 ,"s tell u t ! motion _h be5 nor? & s\?1 :il/ o!rs say t x 0 ea/ & we/4 ,a c]ta9 numb] h recognis$ sev]al motions1 & among/ ! re/ !re w be a few :o h felt a wriggl+ or twi/+4 ,leav+ out exceptional cases1 ! g5]al result obta9$ f p]sonal obs]vation z to ! direction ( an e>?quake ( mod]ate int5sity is extremely indef9ite1 & ! only satisfactory in=mation to be obta9$ is t d]iv$ f in/rum5ts or f ! effects ( ! e>?quake exhibit$ 9 %att]$ build+s & bodies :i* _h be5 ov]turn$ or project$4 ,by ! direction 9 :i* walls1 columns1 & o!r objects _h be5 ov]?r[n or fractur$1 ,mallet 0 enabl$ to det]m9e ! position ( ! orig9 ( ! ,neapolitan e>?quake4 ,simil> ph5om5a h _m times be5 tak5 advantage ( by o!r inve/igators ( e>?quake ph5om5a4 ,effects produc$ ^u /ructures are1 h[ev]1 only to be obs]v$ z ! results ( a de/ructive e>?quake1 at :i* "t cities may be reg>d$ z collections ( seismomet]s4 7,see *apt] on ,effects 9 ,build+s47 ,to det]m9e ! direction ( movem5t dur+ a small e>?quake1 ! mo/ satisfactory me?od appe>s to be an appeal to in/rum5ts4 ,in/rum5ts z ,indicators ( ,direction4--,! relative values ( diff]5t k9ds ( in/rum5ts1 su* z columns1 p5dulums1 & ! l1 z indicators ( direction h already be5 discuss$4 ,by ! use ( p5dulum seismographs x has be5 %[n t dur+ an e>?quake ! gr\nd may move 9 "o1 two1 or sev]al directions 7see p4 #ba72 & x is1 g5]ally speak+1 only 9 ^? cases :]e we exp]i5ce a decid$ %ock 9 ! di/urbance t we c det]m9e ) any confid5ce ! direction 9 :i* ! motion has be5 propagat$4 ,su* directions are usually indicat$ by ! major axis ( c]ta9 m or less elliptical figures :i* h be5 drawn1 :i* 9 !mselves appe> to indicate ! comb9ation ( two rectil9e> movem5ts4 ,results simil> to ^? indicat$ by ! records ( p5dulum seismographs h also be5 obta9$ ^u mov+ plates ) a d\ble bracket seismograph4 ,?us1 9 ! e>?quake :i* %ook ,tokio at #f ,a4,m4 on ,july #e1 #ahha1 !re 7 indications ( ! foll[+ motions3-- ,ne> ! comm5cem5t ( ! %ock ! motion 0 ,n4 #aab ,e4 ,"o & a half second aft] ?is1 ! direction ( motion appe>s to h be5 ,n4 #ej ,e4 ,9 ?ree-f\r?s ( a second m x gradually *ang$ to a direction ,n4 #ade ,e41 & aft] a simil> int]val to ,n4 #fb ,e4 ,half a second aft] ?is x 0 ,n4 #acb ,e41 & f\r seconds lat] ! motion 0 aga9 9 ! orig9al direction--namely1 ,n4 #aab ,e4 ,^! p>ticul> directions ( motion h be5 select$ because !y 7 s def9itely indicat$4 ,! commone/ type ( e>?quake :i* is exp]i5c$ 9 ,japan1 & probably also 9 o!r e>?quake-%ak5 di/ricts1 is ! comp\nd or dia/rophic =m4 ,t e>?quakes (t5 h motions comp\nd$ ( two sets ( vibrations1 has also be5 prov$ by ! analysis ( ! records obta9$ f two compon5t seismographs4 ,f an analysis ( a record ( ?is description1 ,pr(essor ,ew+ has %[n t 9 ! e>?quake felt 9 ,tokio on ,m>* #aa1 #ahha1 !re 7 approximate circul> 7some:at spiral7 movem5ts4 ,?is leads u to ! consid]ation ( ! twi/+ & wriggl+ motions :i* are said to be exp]i5c$ by "s obs]v]s4 ,motions l ^!1 :i* by ! ,italians & ,mexicans are call$ vorticosi1 are usually suppos$ to be ! cause ( objects l *imneys & grave/ones be+ rotat$4 ,^! ph5om5a1 x w be se5 f :at is said 9 ! *apt] ^u ! effects produc$ 9 build+s1 c be m easily expla9$ ^u ! supposition ( a simple rectil9e> movem5t4 ,t at ! "t ( an e>?quake !re may be motion 9 m ?an "o direction has be5 recognis$ s9ce ! "t ( ,ari/otle2 & x is possible t two sets ( rectil9e> motion1 z1 = in/ance1 ! normal & transv]se movem5ts1 may h l$ obs]v]s to imag9e t !re has be5 a twi/+ motion tak+ place1 & ?is especially :5 ! two sets ( movem5ts h quickly succe$$ ea* o!r4 ,p]sons inside flexible build+s may possibly h exp]i5c$ m or less ( a rotatory motion1 al?\gh ! %ock 0 rectil9e>2 ! build+ assum+ su* a motion 9 consequ5ce ( its con/ruction & its position ) reg>d to ! direction ( ! %ock4 ,9 ! case ( de/ructive e>?quakes1 especially at po9ts situat$ practically above ! orig91 ! univ]sal te/imony1 ,mallet tells u1 is t a twi/+1 wriggl+ motion 9 diff]5t planes1 att5d$ by an up-&-d[n movem5t ( great] range1 is exp]i5c$4 ,to su* di/urbances ! ^w sussultatore is sometimes appli$4 ,mallet has giv5 _m elliptical & o!r clos$ curves to illu/rate ! nature ( su* motions4 ,duration ( an ,e>?quake4--,:5 read+ acc\nts ( e>?quakes x is (t5 difficult to det]m9e ! l5g? ( "t a %ak+ 0 cont9u\s4 ,9 ,japan1 9 ,a4,d4 #gde1 !re 0 a %ak+ :i* is said to h la/$ sixty h\rs2 & 9 ,a4,d4 #igg !re 7 a s]ies ( %ak+s la/+ #cjj days4 ,(t5 we meet ) records ( di/urbances :i* h la/$ f tw5ty to sev5ty days4 ,at ,san ,salvador1 9 #ahgi1 m ?an #fjj %ocks 7 felt )9 t5 days2 9 #ahej1 at ,honduras1 !re 7 #ajh %ocks 9 a week2 9 #agdf1 at ,lima1 #bjj %ocks 7 felt 9 tw5ty-f\r h\rs2 at ! isl& ( ,/4 ,?omas1 9 #ahfh1 #bhc %ocks 7 felt dur+ ab\t t5 h\rs4 ,di/urbances l ^!1 :i* succe$ ea* o!r ) suffici5t rapidity to cause an almo/ cont9ual trembl+ 9 ! gr\nd1 may be reg>d$ z collectively =m+ "o great seismic ef=t :i* may la/ a m9ute1 an h\r1 a day1 a week1 or ev5 sev]al ye>s4 ,/rictly speak+1 !y are a s]ies ( sep>ate e>?quakes1 ! resultant vibrations ( :i* m or less ov]lap4 ,:5ev] a l>ge e>?quake occurs x is g5]ally succe$$ by a l>ge numb] ( small] %ocks4 ,! seismic di/urbance z reg>ds "t is1 z ,mallet rem>ks1 v (t5 #8l an occasional cannonade dur+ a cont9u\s b irregul> rattle ( musketry4' ,9 ! ,new ,zeal& e>?quake ( #ahdh1 %ocks cont9u$ = ne>ly five weeks1 & dur+ a l>ge portion ( ! "t !re 7 at lea/ #a1jjj %ocks p] day4#ab ,! e>?quake ( ,lisbon1 :i* 9 five m9utes de/roy$ ! :ole t[n1 0 foll[$ by a s]ies ( di/urbances la/+ ov] sev]al mon?s4 ,aft] ,basle _h1 on ,octob] #ah1 #acef1 be5 laid 9 ru9s1 x is /at$ %ocks foll[$ ea* o!r = a p]iod ( a ye>4 ,! ,calabrian e>?quake 0 cont9u$ ) consid]able /r5g? = a ye>1 & x is said t ! e>? did n come completely to re/ = t5 ye>s4 ,dur+ ?is cannonade ! heavy %ocks ann\nc$1 z !y d 9 mo/ e>?quake c\ntries at ! pres5t day1 a s]ies ( weak] di/urbances4 ,9 c]ta9 exceptional cases ?is ord] ( ev5ts has be5 inv]t$1 & slight %ocks h ann\nc$ ! com+ ( heavy ones4 ,fu*s gives an example ( ?is 9 ! e>?quake ( ,br\ssa1 :5 ! fir/ %ock 0 on ,febru>y #bh1 #ahee4 ,on ,m>* #i & #bc !re 7 heavi] %ocks1 b ! heavie/ did n arrive until ,m>* #bh4 ,"u c]ta9 conditions x is possible to h a s5sible vibration produc$ 9 ! gr\nd :i* is practically ( unlimit$ duration2 ?us1 = in/ance1 x has be5 notic$ t ! fall+ ( wat] at c]ta9 l>ge wat]falls1 by its cont9u\s rhy?mical impact on ! rocks1 produces 9 !m tremors :i* are to be obs]v$ at great di/ances4 ,( ?is ! au?or conv9c$ himself at ! ,falls ( ,niag>a1 :]e he obs]v$ ! reflect$ & ev]-mov+ image ( ! sun 9 a pool ( wat]4 ,"u fav\rable circum/ances almo/ cont9ual cond5sation ( /eam might take place 9 volcanic foci1 ea* cond5sation giv+ rise to a bl[ suffici5tly p[]ful to produce vibrations 9 ! surr\nd+ gr\nd4 ,^? :o h /ood ne> a l>ge geys]1 l ! "o 9 ,icel&1 :5 x makes an ineffectual ef=t to erupt1 w recognise h[ p[]ful su* a cause might be4 ,humboldt has rem>k$ %ocks on ,vesuvius & ,pi*9*a :i* 7 p]iodic1 occurr+ tw5ty to ?irty seconds be=e ea* ejection ( vap\r & a%es4 ,e>?quakes l ^! may be ( va/ ext5t1 gradually spread+ fur!r & fur!r outw>ds4 ,?is spread+ ( e>? vibrations may be obs]v$ at a l>ge factory conta9+ heavy ma*9]y or a /eam hamm]4 ,aft] ! ma*9]y comes to re/1 x is probably "s "t be=e ! gr\nd returns to re/4 ,examples ( di/urbances ( ?is nature are spok5 ( "u ! head ( ,e>? ,tremors4 ,! record ( ! duration ( an ord9>y e>?quake z obs]v$ at a giv5 po9t is dep5d5t ^u ! s5sibility ( our in/rum5ts4 ,cont9u\s motions p]ceptible to our s5ses )\t ! aid ( in/rum5ts usually la/ f ?irty seconds to ab\t two or ?ree m9utes4 ,9 ,japan ! %ocks1 z tim$ by wat*es1 usually la/ f tw5ty to =ty seconds4 ,occasionally a cont9u\s %ak+ is felt = m ?an "o & a half m9utes1 & cases h be5 record$ :]e ! motion has cont9u$ = z mu* z f\r m9utes & ?irty-?ree seconds4 ,seismomet]s hav+ a multiplication ( #f to #ab usually indicate t motion cont9ues long] ?an is p]ceptible to ! s5ses4 ,p]iod ( ,vibration4--,:5 an e>?quake conta9s sev]al prom95t vibrations :i* might be call$ ! %ocks ( ! di/urbance1 our feel+s tell u t ^! h occurr$ at unequal int]vals4 ,ab\t ! "t :i* is tak5 = ! complete backw>d & =w>d oscillation ( ! gr\nd :i* con/itutes ! %ock a little has already be5 said4 ,?is 0 d$uc$ f ! records ( di/urbances z drawn by seismographs4 ,f ! same s\rces we c readily obta9 ! p]iod ( all ! prom95t vibrations 9 a di/urbance4 ,9 any giv5 e>?quake !re are irregul>ities 9 p]iod1 & diff]5t e>?quakes diff] f ea* o!r4 ,ab\t ! e>ly attempts to det]m9e ! p]iod ( e>? vibrations some?+ has be5 said 9 ! *apt] on ,e>?quake ,in/rum5ts4 ,9 ! e>?quake ( ,m>* #aa 7ref]r$ to on p4 #gj7 we f9d t bo? compon5ts comm5c$ ) a s]ies ( small vibrations1 ab\t five or six to ! second2 next came ! %ock1 consi/+ ( two complete vibrations execut$ 9 two seconds4 ,9 ?is x is to be obs]v$ t ! motion ea/w>ds 0 p]=m$ mu* m quickly ?an ! motion we/w>ds4 ,next1 by ref]5ce to ! ea/ & we/ compon5t1 x is se5 t !re are a numb] ( l>ge vibrations1 ab\t "o p] second1 on :i* a numb] ( small] motions are sup]pos$4 ,z ! motion proce$s1 ^! become less & less def9itely pron\nc$ & m irregul> 9 _! int]vals1 until f9ally ! motion dies away4 ,?is e>?quake1 z record$ at ! au?or's h\se 9 ,tokio1 la/$ ab\t "o & a half m9ute4 ,! same e>?quake1 z record$ by ,pr(essor ,ew+ at a /ation situat$ ab\t "o & a half mile di/ant1 b on flat gr\nd1 appe>s to h la/$ f\r & a half m9utes4 ,! l>ge/ wave _h a p]iod ( #jg second4 ,9 ! e>?quake ( ,m>* #h1 #ahha1 !re 7 on an av]age #ad vibrations p] second4 ,^! vibrations 7 execut$ 9 a direction transv]se to ! l9e jo9+ ! obs]v+ /ation & ! locality f :i* ! di/urbance mu/ h orig9at$ z det]m9$ by "t obs]vations4 ,x c1 !re=e1 be assum$ t ^! vibrations1 hav+ s sl[ a p]iod1 7 transv]se motions1 ?is sl[ness or sluggi%ness be+ due to ! fact t ! modulus = di/ortion is less ?an ! modulus :i* gov]ns ! propagation ( normal vibrations4 ,! ,amplitude ( ,e>? ,movem5ts4--,9 mak+ e/imates ( ! di/ances ?r\gh :i* we are mov$ backw>d & =w>d at ! "t ( an e>?quake1 if we judge by our feel+s1 we may (t5 be misl$4 ,if a p]son is out ( doors & walk+1 an e>?quake may take place suffici5tly /rong to cause *imneys to fall & unro( h\ses1 :i*1 s f> z ! actual %ak+ ( ! gr\nd is conc]n$1 w be pass$ by unnotic$4 ,on ! o!r h&1 to p]sons indoors1 especially on an upp] /ory1 x is impossible ev5 = a tremor to pass by )\t creat+ consid]able al>m by ! angul> movem5t t has be5 tak5 up by ! build+4 ,_m obs]v]s h endeav\r$ to make actual measurem5ts ( ! maximum ext5t ?r\gh :i* ! e>? moves at ! "t ( an e>?quake4 ,among ! reports ( ! ,briti% ,association = #ahda is ! report ( a committee :i* _h be5 appo9t$ #8= obta9+ in/rum5ts & regi/]s to record %ocks ( e>?quakes 9 ,scotl& & ,irel&'4 ,we read t 9 "o e>?quake :i* _h be5 measur$ ! displacem5t ( ! gr\nd _h be5 half an in*1 & 9 ano!r x _h be5 less ?an half an in*4 ,! in/rum5ts us$ to make ^! obs]vations dep5d$ ^u ! in]tia ( p5dulums :i* at ! "t ( ! di/urbance 7 suppos$ to rema9 at re/4 ,obs]vations simil> to ^! h be5 made 9 ,japan4 ,"o long s]ies 7 made by ,mr4 ,e4 ,knipp+ = ,dr4 ,gr4 ,wag5]4 ,!y ext5d$ f ,novemb] #ahgh to ,april #ahhj1 & 7 z foll[s3-- ,numb] ( ,maximum horizontal ,e>?quakes motion ( ! gr\nd #aj #j to #jae mm4 #g #ae #je #h #e #be #b #be m ,) 8 app>atus = v]tical motion ,dr4 ,wag5] also made obs]vations on ! absolute v]tical motion4 ,?is seldom rea*$ #jb mm4 ,! greate/ value 0 t obs]v$ = ! de/ructive %ock ( ,feb4 #bb1 #ahhj1 :i* 0 #ef mm4 ,by means ( a numb] ( in/rum5ts di/ribut$ at v>i\s localities r\nd ,tokio1 ! *ief ( :i* 7 p5dulums ) friction po9t]s to r5d] !m #8dead beat1' & ) magnify+ app>atus to %[ ! actual motion ( ! gr\nd1 ! au?or arriv$ at results simil> to ^? obta9$ by ,dr4 ,wag5]--namely1 t ! e>?'s maximum horizontal motion at ! "t ( a small e>?quake 0 usually only ! fraction ( a millimetre1 & x seldom exce$$ ?ree or f\r millimetres4 ,:5 we get a motion ( five or six millimetres1 we usually f9d t brick & /one *imneys h be5 %att]$4 ,! results obta9$ = v]tical motion 7 also v small4 ,9 ,tokio x is seldom t v]tical motion c be detect$1 & :5 x is record$ x is seldom m ?an a millimetre4 ,^! results1 :i* 7 put =w>d "s ye>s ago1 h s9ce receiv$ confirmation by ! use ( a v>iety ( in/rum5ts 9 ! h&s ( diff]5t obs]v]s4 ,mallet1 9 8 acc\nt ( ! ,neapolitan e>?quake ( #aheg1 approximat$ to ! amplitude ( an e>? p>ticle by obs]v+ ! wid?1 at ! level ( ! c5tre ( gravity1 ( fissures =m$ ?r\gh & rema9+ 9 great masses ( v inela/ic masonry4 ,tak+ /ations situat$ on or v ne>ly on ! same l9e pass+ ?r\gh ! seismic v]tical 7epic5trum71 ,mallet obs]v$ ! amplitude increas$ z "s function ( ! di/ance1 z w be se5 f ! foll[+ table3-- ---------------------------------------- --------------------- ,/ation ,polla ,la ,sala,c]tosa,tramutola,s>coni ---------------------------------------- --------------------- ,di/ance f ,seismic ,v]tical 9 #cde #aafj #afej #bjfj #bfg geographical miles ,amplitude 9 in*es #be #ce #dj #de #dge ---------------------------------------- --------------------- ,! possibility ( a law su* z ?is hav+ an exi/5ce = places at a di/ance f ! seismic v]tical comp>able ) ! v]tical dep? ( ! c5trum w be %[n f>!r on4 ,) reg>d to ! maximum displacem5t ( an e>? p>ticle4 ,mallet 0 ( op9ion t !re 0 evid5ce to %[ t x _h 9 "s cases be5 ov] "o foot4 ,m4 ,abella1 9 an e>?quake :i* occurr$ 9 ! ,philipp9es 9 #ahha1 made a r\gh obs]vation ( ! motion ( ! e>? to a di/ance ( ab\t two metres4 ,?is1 z might be expect$1 0 beyond ! ela/ic limits ( ! mat]ial1 & caus$ fissures to be =m$1 :i* 7 se5 to op5 & %ut4 ,int5sity ( ,e>?quakes4--,9 speak+ ( ! /r5g? ( an e>?quake1 we usually employ t]ms l #8weak1' #8/rong1' #8viol5t1' c4 ,al?\gh ^! expressions1 accompani$ by illu/ration ( ! effects :i* an e>? quake has produc$1 convey a g5]al idea ( ! /r5g? ( a %ock z felt at "s p>ticul> locality1 our ideas nev]!less want+ 9 def9it5ess2 & if we endeav\r to comp>e "o %ock ) ano!r1 z a :ole1 our want ( exactness is augm5t$4 ,we h se5 t ,palmi]i's seismograph indicates int5sity by a c]ta9 numb] ( degrees1 :i*1 to a c]ta9 ext5t1 is a measure ( ! viol5ce ( ! motion z indicat$ at a p>ticul> locality4 ,! degrees1 z be=e /at$1 ref] to ! height to :i* 9 consequ5ce ( ! %ak+1 a c]ta9 quantity ( m]cury 0 wa%$ 9 a tube1 :i* is a function ( ! dep? ( m]cury 9 ! tube1 & also ( ! duration ( ! di/urbance4 ,f ?is x seems possible t a v sl[ motion ( small amplitude1 cont9u+ ov] a suffici5t p]iod ( "t1 might1 if x agre$ ) ! p]iod ( ! m]cury1 indicate an e>?quake ( _m degrees ( int5sity1 :il/ resid5ts 9 ! neighb\rhood might n h notic$ ! di/urbance2 &1 on ! o!r h&1 a %ort b int5se %ock creat+ consid]able de/ruction might h be5 record$ z ( only a few degrees ( int5sity4 ,al?\gh objections l ^! might be rais$ to su* a me?od ( record+ int5sity1 9 practice x w\ld appe> t su* results are n pron\nc$1 & ! indications ( ! in/rum5t usually give u approximate indications ( relative int5sity4 ,9 writ+ ab\t ! ,neapolitan e>?quake ( #aheg1 ,mallet says t #8area alone af=ds no te/ ( seismic en]gy4' ,! area ov] :i* a %ock is felt w dep5d n only ^u ! initial =ce ( ! di/urbance1 b also ^u ! focal dep? ( a %ock1 ! =m & position ( t focus1 ! duration ( ! di/urbance1 & ! nature & arrangem5t ( ! mat]ials :i* are %ak54 ,f obs]vations 9 ,japan1 x is cle>ly %[n t massive m\nta9 ranges ex]t a consid]able influ5ce ^u ! ext5sion ( seismal di/urbances4 ,on "o side ( a l>ge range ( m\nta9s l>ge cities might be laid 9 ru9s1 :il/ on ! o!r side ! di/urbance creat+ ?is de/ruction might n be notic$4 ,velocity & ,accel]ation ( an ,e>? ,p>ticle4--,we n[ pass on to me?ods ( det]m9+ ! int5sity ( an e>?quake :i* are less arbitr>y ?an ^? :i* h j be5 discuss$4 ,^! me?ods h already be5 discuss$ :5 speak+ ( artificial di/urbances1 :]e x 0 %[n t ! int5sity ( an e>?quake z measur$ by its de/ructive effects greatly dep5d$ ^u ! sudd5ness ) :i* ! backw>d & =w>d motions ( ! gr\nd 7 comm5c$ or end$4 ,among/ ! e>li] inve/igators ( seismic ph5om5a :o obs]v$ t !re exi/$ a connection betwe5 ! di/ance to :i* bodies _h be5 project$ dur+ an e>?quake & ! sudd5ness or initial velocity ) :i* ! gr\nd _h be5 mov$ b5ea? !m1 0 ,pr(essor ,w5?rop ( ,cambridge1 ,massa*usetts1 :o not$ t bricks f 8 *imneys _h1 by ! ,new ,engl& e>?quake ( #agee1 be5 ?r[n ?irty feet4 ,f ?is & ! kn[n height ( ! *imney1 he calculates t ! bricks _h be5 project$ ) an initial velocity ( tw5ty-"o feet p] second4#ac ,! calculations made by ,mallet respect+ ! maximum velocity ( an e>? p>ticle at ! "t ( ! ,neapolitan e>?quake 9 #aheg dep5d$ ^u ! ov]?r[1 projection1 & fracture ( bodies4 ,! pr9ciples :i* guid$ him 9 mak+ ! calculations w be und]/ood f ! foll[+ illu/ration4 ,illu/ration3 ,fig4 #ad4 ,if a column1 ,a ,b ,c ,d1 receive a %ock or be sudd5ly mov$ 9 ! direction ( ! arr[1 ! c5tre ( gravity1 ,g1 ( ?is column w revolve r\nd ! edge1 & t5d to describe ! pa? ,g ,o4 ,if x passes ,o1 ! column w fall4 ,! "w done 9 su* a case z ?is is equal to lift+ ! column ?r\gh ! height o h4 ,if ,g ,a a1 ! angle ,g ,a h 1 & ! weight ( ! body ,w1 !n ! above "w equals ,wa 7#a - cos 74 ,?is mu/ equal ! "w acquir$--t is to say1 ! k9etic en]gy ( rotation ( ! body1 or ,w w#b ,k#b ,wa 7#a - cos 7 ----------------------4 #b g ,:]e w is ! angul> velocity ( ! body at />t+1 ,k ! radius ( gyration r\nd ,a1 & g ! velocity acquir$ by a fall+ body 9 "o second4 ,:5ce w#b ,k#b #b ga 7#a - cos 71 b w1 ! angul> velocity1 is equal to ! /atical c\ple appli$1 divid$ by ! mom5t ( in]tia1 or1 ,va cos w --------------------1 ,k#b squ>+ & sub/itut+ ,k#b #a - cos ,v#b #b;g ------ ------------------1 a cos#b ,k#b & s9ce ! l5g? ( ! correspond+ p5dulum is l ------1 a #a - cos ,v#b #b;gl ------------------4 cos#b ,to apply ?is to any giv5 case we mu/ f9d ! value ( l or ( ,k#b ------4 a ,mallet f9ds ^! values = ! cube1 solid & holl[ rectangul> p>allelopip$s1 solid & holl[ cyl9d]s1 c4 ,9 ^! =mul we h a direct connection betwe5 ! dim5sions & =m ( a body & ! velocity ) :i* ! gr\nd mu/ move b5ea? x to cause its ov]?r[4 ,illu/ration3 ,,fig4 #ae4 ,n only is ! case discuss$ = horizontal =ces1 b also = =ces act+ obliquely4 ,simil> reason+s are appli$ to ! productions ( fractures 9 walls1 b z !re is unc]ta9ty 9 our k ( ! co-effici5t ( =ce necess>y to produce fracture ?r\gh jo9ts across b$s ( masonry1 ! d$uctions ought n to be appli$ z ! measures ( velocity4 ,:]e ! fractures occur at ! base or 9 horizontal planes1 or 9 ^? ( ! cont9u\s b$s ( ! masonry1 or ?r\gh homog5e\s bodies1 ! unc]ta9ty is n s great1 & = cases l ^! ,mallet gives sev]al illu/rations4 ,! di/ance to :i* bodies _h be5 project$1 z1 = example1 ornam5ts f ! tops ( p$e/als1 cop+-/ones f ! edges ( ro(s1 7 also us$ z means ( det]m9+ ! angle at :i* ! %ock _h em]g$1 or1 if ?is be kn[n1 = det]m9+ ! velocity4 ,?us by a %ock 9 ! direction ,o ,c1 a ball1 ,a1 on ! top ( a p$e/al w\ld describe a trajectory to ! po9t ,c4 ,let ! angle :i* ,o ,c makes ) ! horizon be e1 ! v]tical height ?r\gh :i* ! ball has fall5 be b1 & ! horizontal di/ance ( projection be a2 !n a#b b a tan e ------------------------1 #d;,h cos#b e ,h be+ ! height due to ! velocity ( projection4 ,:5ce #b;,h #d;,h7,h b7 - a#b ,tan e ---------------------------------------- ------------4 a a#b g ,v#b ---------------------------------------- ----------------------4 #b cos#b e 7b - a tan e7 ,= ! back motion or subnormal wave 9 ! direction ,c ,o1 #b;,h #d;,h7,h b7 - a#b ,tan e ---------------------------------------- ------------4 a a#b g ,v#b ---------------------------------------- ----------------------4 #b cos#b e 7b a tan e7 ,a s]i\s error :i* may ent] into calculations ( ?is description :5 practically appli$ has be5 po9t$ out :5 speak+ ( columns z seismomet]s4 ,x 0 !n %[n t su* bodies be=e be+ ov]?r[n may (t5 be caus$ to rock1 & !re=e t _! f9al ov]?r[ may n h any direct connection ) ! impulse ( ! succe$+ %ock4 ,ano!r po9t to :i* att5tion mu/ be drawn respect+ ! above calculations is t if !re 0 no friction or adh]5ce betwe5 ! project$ body & its p$e/al1 9 consequ5ce ( its in]tia x w\ld be left beh9d by ! =w>d motion ( ! %ock1 & simply drop at ! foot ( its support4 ,9 ! case ( frictional adh]5ce x w\ld be c>ri$ =w>d by ! velocity acquir$ be=e ?is adh]5ce 0 brok51 & ?r[n 9 a direction opposite to t giv5 9 ! figure--t is to say1 9 ! direction ( ! %ock4#ad ,! ,absolute ,int5sity ( ! ,=ce ex]t$ by an ,e>?quake4--,no d\bt x has occurr$ to _m :o h exp]i5c$ an e>?quake t ! p[] :i* gave bir? to su* a di/urbance mu/ h be5 enorm\sly great4 ,! e/imates :i* we %all make ( ! absolute am\nt ( en]gy repres5t$ by an e>?quake _c1 on acc\nt ( ! nature ( ! factors ) :i* we deal1 be reg>d$ z accurate4 ,!y may1 h[ev]1 be ( assi/ance 9 =m+ e/imates ( quantities ab\t :i* we h at pres5t no conception4 ,"o me?od ( obta9+ ! result we seek is t :i* 0 employ$ by ,mallet 9 8 calculations respect+ ! ,neapolitan e>?quake4 ,al?\gh disbeliev+ 9 ! g5]al increm5t ( temp]ature z we desc5d 9 ! e>? at an av]age rate ( #a ,f4 = e fifty or sixty feet ( desc5t1 = want ( bett] means4 ,mallet assumes ?is law to be true1 &1 kn[+ f a v>iety ( obs]vations ! dep? ( v>i\s p>ts ( ! cavity f :i* ! di/urbance sprang1 he calculates ! temp]atures ( ?is cavity 9 v>i\s p>ts z due to its dep? b5ea? ! surface4 ,next1 x is assum$ t /eam 0 sudd5ly admitt$ into ?is cavity1 :i* might ex]t ! greate/ possible pressure due to ! maximum temp]ature4 ,?is 0 calculat$ z be+ ab\t #fhd atmosph]es4 ,next1 he det]m9$ ! column ( lime/one necess>y to balance su* a pressure1 :i* is ab\t #h1eej feet 9 height4 ,z ! lea/ ?ickness ( /rata above ?is cavity 0 #af1gjj feet1 ! pressure ( #fhd atmosph]es 0 n suffici5t to bl[ away its cov]1 b if sudd5ly admitt$ or g5]at$ 9 ! cavity x might h produc$ ! wave ( impulse by ! sudd5 compression ( ! walls ( ! cavity4 ,! pressure ( #fhd atmosph]es is equival5t to ab\t #deh tons on ! squ>e in*1 &1 z ! total area ( ! walls ( ! cavity is calculat$ at tw5ty-sev5 squ>e miles1 ! total accumulat$ pressure w\ld be m ?an #fdj1ebh millions ( tons4 ,mallet1 h[ev]1 %[s t x is probable t ! temp]ature ( ! focal cavity 0 mu* great] ?an t due to ! hypogeal increm5t1 & t !re=e ! pressure may h be5 great]4 ,! capability ( produc+ ! e>?quake impulse1 h[ev]1 dep5ds on ! sudd5ness ) :i* ! /eam is fla%$ (f4 ,accord+ to ! exp]im5ts ( ,b\tigny & o!rs1 ,mallet tells u t ! mo/ sudd5 production ( /eam w\ld take place at a temp]ature ( #ejj-eej ,c41 :i* is b a few degrees bel[ t calculat$ = ! mean focal dep?4 ,assum+ ! above calculat$ pressure to be true1 & kn[+ ! co-effici5t ( compression ( ! mat]ials on :i* x act$1 ! volume ( ! wave at a giv5 mom5t ne> ! in/ant ( />t+--t is1 at ! focus--c be calculat$1 & f ?is ! wave amplitude on rea*+ ! surface may be d$uc$4 ,proce$+ backw>ds1 if we h obs]v$ ! wave amplitude1 calculat$ ! dep? ( ! focus1 & "k ! co-effici5t ( expansion1 !n ! total compression may be calculat$ & ! temp]ature due to ! pressure produc+ ?is may be arriv$ at4 ,9 ?is way e>?quakes may be us$ z a means ( calculat+ subt]ranean temp]ature at dep?s t c nev] be atta9$ exp]im5tally4 ,a me?od ( proce$+ :i* is probably m def9ite ?an t adopt$ by ,mallet w\ld be ! application ( ! me?od indicat$ :5 speak+ ( ! int5sity ( artificial di/urbances4 ,if = a giv5 e>?quake ! orig9 ( :i* is kn[n we h det]m9$ by seismographs ! mean accel]ation ( an e>? p>ticle at two or m /ations at diff]5t di/ances f t orig91 we are enabl$ to con/ruct a curve ( int5sity ! area betwe5 :i* & its asymptotes 0 %[n to be a measure ( ! total int5sity ( ! %ock4 ,comp>+ ?is area ) t ( a unit di/urbance produc$1 say1 by ! explosion ( a p\nd ( dynamite1 "o may approximately calculate 9 t]ms ( ?is unit ! initial int5sity ( ! e>?quake4 ,radiation ( an ,e>?quake4--,! tremors prec$+ ! m viol5t movem5ts ( an e>?quake may be due1 z ,mallet has sugge/$1#ae to ! free surface waves rea*+ a di/ant po9t be=e ! direct vibrations4 ,! fact t e>? vibrations produc$ by /rik+ a bl[ on or ne> ! surface ( ! gr\nd are :olly oblit]at$ 9 rea*+ a cutt+ or valley1 !re be+ no und]gr\nd waves ( di/ortion to crop up on ! opposite side ( ! valley1 indicates t ! di/urbance is "o t travels on ! surface2 ! same fact is illu/rat$ :5 we endeav\r to transmit vibrations ?r\gh ! side ( a hill into a tunnel4 ,9 ! tunnel1 al?\gh ! di/ance may be small1 no s5sible effects are produc$1 :il/ ! same di/urbance may be record$ at a long di/ance f its orig9 on ! surface ( ! gr\nd outside ! tunnel4 ,la/ly1 we may ref] to ! exp]i5ces ( m9]s und]gr\nd4 ,occasionally x has happ5$ t m9]s :5 deep und]gr\nd1 z 9 ! ,m>i5b]g 9 ! ,saxon ,erzgebirge1 h felt %ocks :i* h n be5 notic$ on ! surface4 ,^! obs]vations are r>e1 & x is possible t !y may be expla9$ by ! cav+ 9 ( subt]ranean excavations4 ,! usual exp]i5ce is1 t if a %ock is felt und]gr\nd x is also felt on ! surface1 z = example 9 ! lead m9es 9 ,d]by%ire at ! "t ( ! ,lisbon di/urbance 7#agee74 ,! mo/ frequ5t obs]vation1 h[ev]1 is t a %ock may be felt on ! surface :ile x is n rem>k$ by ! m9]s b5ea? ! surface1 z at ,fahlun & ,presburg 9 ,novemb]1 #ahbc4 ,at ! ,com/ock ,lode 9 ,colorado ab\t twelve ye>s ago _m e>?quakes 7 felt4 ,on "o p>ticul> day tw5ty-f\r 7 c\nt$4 ,sup]9t5d5t ,*>les ,=eman told ! au?or :5 he visit$ ,virg9ia ,city 9 #ahhb1 t special obs]vations 7 made to det]m9e :e!r ^! %ocks 7 felt z sev]ely deep d[n 9 ! m9es z on ! surface1 :]e !y 7 on ! v]ge ( be+ de/ructive4 ,! univ]sal te/imony ( _m obs]v]s 0 t 9 mo/ cases !y 7 n felt at all und]gr\nd1 & :5 a %ock 0 felt x 0 extremely feeble4 ,at ,taka%ima ,colli]y1 9 ,japan1 x is seldom t %ocks are felt und]gr\nd4 ,! explanation ( ^! latt] obs]vations appe>s to be ei!r t1 9 consequ5ce ( a small] amplitude ( motion 9 ! solid rocks b5ea? ! surface z comp>$ ) ! ext5t ( motion on ! surface1 ! di/urbances are pass$ by unnotic$1 or else ! di/urbance is1 at a di/ance f its orig91 practically conf9$ to ! surface4 ,velocity ( ,propagation ( an ,e>?quake4--,al?\gh _m h writt5 ^u e>?quakes & h endeav\r$ to give to u ! velocity ) :i* !y 7 propagat$1 ! subject is "o ab\t :i* we h z yet b little exact in=mation4 ,! importance ( ?is bran* ( inve/igation is und\bt$ly great4 ,by kn[+ ! velocity ) :i* an e>?quake has travell$ 9 v>i\s directions we are assi/$ 9 det]m9+ ! locality ( its orig92 we may possibly make important d$uctions respect+ ! nature ( ! m$ium ?r\gh :i* x has pass$2 p]haps also we may le>n some?+ reg>d+ ! int5sity ( ! di/urbance :i* creat$ ! e>?quake4 ,9 ! ,report ( ! ,briti% ,association = #ahea ,mallet gives ! table on next page1 9 :i* are plac$ toge!r ! approximate rates ( transit ( %ocks ( sev]al e>?quakes :i* he discusses4 ,"s ( ^!1 x w be obs]v$1 are records ( di/urbances :i* mu/ h pass$ ?r\gh or across ! b$ ( ! ocean4 ,9 ,mallet's ,briti% ,association ,report = #aheh1 he gives data compil$ by ,mr4 ,david ,milne#af respect+ ! ,lisbon e>?quakes ( #agee & #agfa1 f :i* data ! tables ( velocities 7p4 #hi7 h be5 calculat$1 omitt+ ^? :i* ,mr4 ,mallet has m>k$ z unc]ta94 ,! di/ances are m>k$ 9 degrees ( sev5ty ,engli% miles ea*1 & ! "t is r$uc$ to ,lisbon "t4 ---------------------------------------- ------------------------ ,approx4 rate 9 ,=mation con/itut+ ,occasion & ,place feet ,range on surface z f> ,au?ority p] z kn[n or conjectur$ second ---------------------------------------- ------------------------ ,rev4 ,john ,mit*ell's #a1gfj ,sea bottom1 probably on ,mit*ell guesses f ! slates1 second>y & ,lisbon e>?quakes cry/all9e rocks ,von ,humboldt's #a1gfj ,f obs]vations 9 ,humboldt guesses f ,s\? to v>i\s ,s\? ,am]ican ,am]ica #b1dfd rocks 9 great "p volcanic ,lisbon ,e>?quake ( #agfa4 ,lisbon to ,corunna #a1iid ,transition1 c>bonif]\s #8,annual & granitoid ,regi/]' ,lisbon to ,cork #e1bbh ,transition1 c>bonif]\s cry/all9e slates & granitoid1 probably1 "u sea bottom ,lisbon to ,santa ,cruz #c1bfa ,! same ) _m alt]ations ,antilles4 ,po9te ,pitre to #f1ehf ,probably volcanic rocks ,/i] & ,cay5ne 7d\btful7 "u sea bottom ,p]rey's memoran- dum1 ,dijon ,india4 ,cut* to ,calcutta1 #a1agc ,alluvial1 second>y1 #8,royal #ahai granitoid & lat] ,asiatic igne\s rocks ,j\rnal' ,india1 ,nepauls1 & bas9 ( ! ,ganges1 #ahcd3-- ,rungpur to ,arrah #b1cad ,deep alluvia1 ) #8,royal ,monghyr to ,gorackpur #c1ebj occasional transition1 ,asiatic ,rungpur to ,monghyr #iij c>bonif]\s1 granitoid1 ,j\rnal' ,rungpur to ,calcutta #a1baj & lat] igne\s rocks ,%ips #8,rambl]' & #a1jef ,sea bottom re/+ on #8,nautical #8,millwood1' at sea1 unkn[n rock ,magaz9e' #ahea2 betwe5 lat4 #af #cj ,n4,l41 #ed #cj ,w41 & lat4 #bc #cj ,n4,l41 #eh #j ,w4 ---------------------------------------- ------------------------ ,,! ,,lisbon ,,e>?quake ,,on ,,novemb] #a1 #agee4 ---------------------------------------- ------------- ,mom5t ,di/ance,velocity ,localities obs]v$ f 9 feet ( %ock presum$ p] orig9 second ---------------------------------------- ------------- h4 m4 ,presum$ focus ( %ock1 #i #bc -- -- lat4 #cj1 long4 #aa ,w4 ,a %ip at sea 9 lat4 #ch1 #i #bd #j #cj #c1jia long4 #aj #dg ,w4 ,col>es #i #cj #a #cj #a1cbe ,lisbon #i #cb #a #cj #a1jcj ,oporto #i #ch #b #cj #a1jcj ,ayamont #i #ej #d #j #iaf ,cadiz #i #dh #e #j #a1bcf ,tangi] & ,tetuan #i #df #e #cj #a1dgh ,madrid #i #dc #f #j #a1hee ,fun*al #aj #a #h #cj #a1chb ,portsm\? #aj #c #ab #cj #a1dca ,havre #aj #bc #ac #j #a1cci ,read+ #aj #bg #ac #cj #a1cjd ,y>m\? #aj #db #ae #j #a1agd ,am/]dam #aj #f #ag #j #b1ddd ,lo* ,ness #aj #db #ah #j #a1dji ---------------------------------------- ------------- ,,! ,,lisbon ,,e>?quake ,,( ,,m>* #ca1 #agfa4ag ---------------------------------------- ------------- ,mom5t ,di/ance,velocity ,localities obs]v$ f 9 feet ( %ock presum$ p] orig9 second ---------------------------------------- ------------- h4 m4 ,presum$ focus1 lat4 #dc1 #aa #ea -- -- long4 #aa ,w4 ,%ip at sea 9 lat4 #dc1 _m leagues f coa/ #aa #eb #j #cj #c1jia ( ,portugal ,%ip 9 lat4 #dd #h & #aa #ed #a #de #c1fjg ab\t #hj leagues f coa/ ,corunna #aa #ea #b #cj #b1egf ,%ip lat4 #dd #h & #hj leagues ,,nnw4 ( ,cape #aa #eh #c #cj #c1jia ,f9i/]re ,lisbon noon #d #cj #c1jia ,madeira #ab #f #aj #j #d1abb ,cork #ab #aa #i #cj #b1icg ---------------------------------------- ------------- ,^! tables1 ow+ to ! nature ( ! mat]ials :i* ,mallet _h at 8 disposal1 are b rude approximations to ! tru?4 ,two int]e/+ facts are1 h[ev]1 obs]vable3 ! fir/ be+ t ! velocities = ! e>?quake ( #agfa are mu* high] ?an ^? obta9$ = ! e>?quake ( #agee2 &1 secondly1 t 9 bo? cases ! velocities z det]m9$ f ! obs]vations ( %ips at sea closely approximate to ea* o!r1 9 all cases be+ ne>ly ! same z t ) :i* a s\nd wave w\ld travel ?r\gh wat]4 ,! great diff]5ces 9 transit velocity obta9$ = diff]5t e>?quakes is a po9t wor?y ( att5tion4 ,seeba*'s velocity is a true transit velocity1 & its det]m9ation is dep5d5t on ! assumption t ! %ock radiat$ f ! c5trum & n f ! epic5trum1 ,seeba*'s me?od is expla9$ :5 speak+ ab\t ! det]m9ation ( orig9s4 ,"s int]e/+ obs]vations on ! velocity ) :i* ! e>?quake ( ,octob] #g1 #ahgd1 0 propagat$1 are giv5 by ,m4 ,s4 di ,rossi4#ah ,"o assumption is t ! di/urbance radiat$ f an orig9 to surr\nd+ po9ts ( obs]vation1 :il/ ano!r is t ! di/urbance foll[$ natural fractures1 ! direction ( :i* is d]iv$ f ! cre/ ( c]ta9 m\nta9 ranges4 ,^! velocities are z foll[s1 ,m>adi be+ at or ne> ! orig9 ( ! di/urbance3-- ---------------------------------------- ------------------------ ,velocity 9 feet p] second ,velocity 9 feet p] second by ) direct radiation propagation along m\nta9 *a9s ---------------------------------------- ------------------------ ,modigliana #hbj ,by ! ,valley ( ,m>5zo #a1jhj ,bologna #fef ,sav5o #a1jhj ,=li #hgd ,montone #a1jhj ,mod5a #eah ,pan>o #a1jhj #ihd ,fir5ze #bgc ,sieve #edj ,compiobbi #cbh #edj ---------------------------------------- ------------------------ ,ano!r set ( int]e/+ results are ^? ( ,p4 ,s]pi]i on ! e>?quake ( ,m>* #ab1 #ahgc4 ,! curi\s mann] 9 :i* ?is %ock radiat$ is describ$ 9 ! *apt] on ! ,geographical ,di/ribution ( ,e>?quakes 7see p4 #bca74 ,two l>ge areas appe> to h be5 almo/ simultane\sly /ruck1 s t1 !re be+ no "t = ela/ic yield+1 ! velocities calculat$ betwe5 places situat$ on ei!r ( ! areas are exce$+ly great4#ai ,f ,ragusa to ,v5ice ! velocity 0 #b1gcd feet p] second ,spoleto #d1aja ,p]ugia to ,orvieto #fja ,ancona #a1fdj ,rome #a1fdj or1 #b1ahf ,! foll[+ are examples ( approximate e>?quake velocities :i* h be5 det]m9$ 9 ,japan4 ,! ,tokio ,e>?quake ( ,octob] #be1 #ahha4--;,f records respect+ ?is e>?quake x appe>s to h be5 felt ov] ! :ole ( ,yezo & ! nor!rn & ea/]n coa/ ( ,nipon1 a little f>!r s\? ?an ,tokio4 ,x 0 sev]e/ at ,nemuro & ,hakodate1 & at ! =m] place a little damage 0 done4 ,f ^! facts1 toge!r ) ! indications ( in/rum5ts record+ direction ( movem5t & a g5]al inspection ( ! "t records1 x seems t ! di/urbance mu/ h orig9at$ b5ea? ! sea on ! ea/ coa/ ( ,yezo at a v long di/ance to ! nor?-ea/ ( ,tokio1 f :i* place x pass$ 9 a practically direct l9e on to ,yokohama4 ,z ! di/urbance 0 felt at ,yokohama tw5ty-"o seconds lat] ?an at ,tokio1 & ! di/ances betwe5 ^! two places is ab\t sixte5 geographical miles1 = ?is portion ( its c\rse ! di/urbance mu/ h travell$ at a rate ( at lea/ #d1cjj feet p] second4 ,if we assume t ! %ock1 aft] hav+ rea*$ ,hakodate1 travell$ on at ! same rate z x did betwe5 ,tokio & ,yokohama 9 ord] to rea* ,saporo1 :]e ! %ak+ 0 felt eighte5 seconds aft] ,hakodate1 x mu/ h _h ab\t ?irte5 geographical miles to travel aft] ,hakodate 0 %ak5 be=e ,saporo felt its effect4 ,draw+ f ,hakodate a tang5t to ! ea/]n side ( a circle ( ?irte5 miles radius describ$ r\nd ,saporo1 ! orig9 ( ! di/urbance mu/ be on ! l9e bisect+ ?is tang5t at "r angles4 ,z x also lies on a l9e drawn ?r\gh ,tokio & ,yokohama1 x lies 9 a position ab\t #da ,n4 lat4 & #add #ae ,e4 long41 :i* is a position some:at ne>] to ,nemuro ?an ,hakodate1 z we %\ld anticipate4 ,if ?is be tak5 z approximately indicat+ ! orig91 !n ! %ock1 aft] rea*+ ,hakodate f ! ,hakodate homosei/1 travell$ ab\t #bah miles to rea* ,tokio 9 #abh seconds1 :i* gives a velocity ( #aj1bai feet p] second4 ,! me?od "h foll[$ is equival5t to t ( ! hyp]bola & "o direction 7see p4 #bjd74 ,! hyp]bola is describ$ on ! assumption t ! velocity d$uc$ f ! "t tak5 to travel betwe5 ,tokio & ,yokohama is correct1 & also t ! e>? waves travell$ ) approximately ! same velocity 9 ! vic9ity ( ,saporo z ne> ,tokio4 ,! probability1 h[ev]1 is t !y travell$ m quickly4 ,if ?is be s1 !n ! orig9 is ?r[n some:at to ! s\?-ea/ & ! velocity betwe5 ! ,hakodate homosei/ & ,tokio r$uc$4 ,?us1 if ! velocity 9 ! ,saporo di/rict be d\ble t obs]v$ 9 ! ,tokio di/rict1 ! orig9 is %ift$ ab\t tw5ty-eight miles to ! s\?-we/1 & ! la/-m5tion$ velocity is r$uc$ to ab\t #i1jjj feet p] second4 ,if we "w by ! me?od ( circles1 & assume ! velocity to h be5 con/ant 9 all directions1 !n ?is velocity mu/ h be5 ab\t #f1jjj feet p] second4 ,if we assume t ! indications ( direction obta9$ f seismographs & o!r s\rces give to u by ?is int]section a prop] orig91 ! velocity 9 "s directions may h be5 z mu* z #ag1jjj feet p] second4 ,an orig9 ?us det]m9$1 or ev5 if det]m9$ by ! me?od ( circles1 is 9 discord ) ! fact t places l ,nemuro1 9 ! nor?-ea/ ( ,yezo1 7 ne>] to ! orig9 ?an any ( ! o!r places :i* h be5 m5tion$4 ,! conclusion :i* we are !re=e l$ to ) reg>d to ?is %ock1 assum+ ( c\rse t ! "t obs]vations are tol]ably correct1 is t ! velocity ( propagation 0 v>iable1 be+ great] :5 measur$ betwe5 po9ts ne> to ! orig9 ?an betwe5 po9ts at a di/ance4 ,! velocities e/imat$ v>y betwe5 #d1jjj & #i1jjj feet p] second4 ,9 ! case ( ! e>?quake :i* has j be5 discuss$1 we h an example ( a di/urbance :i* mu/ h pass$ betwe5 ,tokio & ,yokohama 9 :at 0 almo/ a /raight l9e f ! orig94 ,z ?is direction ought to give ! maximum "t ( transit if all e>?quakes are propagat$ ) ! same velocity1 ! foll[+ table is giv5 ( ! int]val betwe5 ! "t ( obs]vation ( sev]al %ocks at ^! two /ations3-- ,,f ,,yokohama ,,to ,,tokio4 ,,f ,,tokio ,,to ,,yokohama4 #ahhj ,decemb] #bj? #cf seconds #ahhb ,octob] #be? #ba seconds #ahha ,janu>y #g? #ad-ca #ahhc ,febru>y #f? #bc ,m>* #h? #fj ,m>* #a #ec #ag?4 #ff #fc ,novemb] #ae? #ca #h? #bg #ahhb ,febru>y #af? #bb #aa? #bf ,z ^! are obs]vations :i* h be5 made ) ! assi/ance ( a telegraphic signal daily employ$ to correct & rate ! clocks f :i* ! obs]vations 7 obta9$1 !y may be reg>d$ z be+ tol]ably1 correct4 ,! di/urbance ( ,febru>y #f1 ! two %ocks ( ,m>* #a1 appe>1 l t ( ,octob] #be1 to h pass$ 9 almo/ a direct l9e f an orig9 9 ! ,n4,n4,e1 ?r\gh ,tokio on to ,yokohama4 ,_! velocities ( propagation z calculat$ f ! above int]vals are approximately #c1ijj1 #a1ijj1 & #a1djj feet p] second4 ,! %ock ( ,febru>y #af appe>s to h _h its orig9 ne> to a po9t 9 ,y$o ,bay ab\t eight miles ea/ ( ,yokohama4 ,assum+ ?is to be ! case1 ! %ock betwe5 ! ,yokohama homosei/ & ,tokio travell$ at ! rate ( #b1ded feet p] second1 b betwe5 ! ,tokio homosei/ & ,*iba at ! rate ( #gej feet p] second2 t is to say1 ! velocity ( propagation rapidly decreas$ z ! di/urbance spread outw>ds4 ,at ,yokohama x 0 record$ at #e4ca4ed1 at ,tokio at #e4cb4af1 & at ,*iba at #e4cc4dh4 ,^! times are giv5 9 ,tokio mean "t4 ,! %ock ( ,m>* #aa1 :i* 0 record$ at ,tokio at #g4ea4bb ,p4,m4 & at ,yokohama at #g4ea4cc ,p4,m41 appe>s1 f ! indications ( in/rum5ts :i* 7 exceptionally def9ite 9 _! records1 to h orig9at$ 9 ! ,n4,e4 corn] ( ,y$o ,bay1 ab\t n9ete5 miles ,s4,s4,w4 f ,*iba4 ,?is %ock 0 r sev]e1 fractur+ sev]al *imneys4 ,f ! ,tokio homosei/ x appe>s to h travell$ on to ,yokohama at ! rate ( ab\t #b1bjj feet p] second4 ,assum+ ^! obs]vations to be approximately accurate1 if we take !m ) ! records ( previ\s obs]v]s !y lead u to ! foll[+ conclusions3-- #a4 ,diff]5t e>?quakes1 al?\gh !y may travel across ! same c\ntry1 h v v>iable velocities1 v>y+ betwe5 sev]al hundr$s & sev]al ?\s&s ( feet p] second4 #b4 ,! same e>?quake travels m quickly across di/ricts ne> to its orig9 ?an x does across di/ricts :i* are f> remov$4 #c4 ,! great] ! int5sity ( ! %ock ! great] is ! velocity4 ,,*apt] ,,vi4 ,,effects ,,produc$ ,,by ,,e>?quakes ,,^u ,,build+s4 ,! de/ruction ( build+s is n irregul>--,cracks 9 build+s--,build+s 9 ,tokio--,relation ( de/ruction to e>?quake motion--,measurem5t ( relative motion ( p>ts ( a build+ %ak5 by an e>?quake--,prev5tion ( cracks--,direction ( cracks--,! pit* ( ro(s--,relative position ( op5+s 9 a wall--,! la/ h\se 9 a r[--,! sw+ ( build+s--,pr9ciple ( relative vibrational p]iods4 ,! subject ( ?is *apt] is1 f a practical po9t ( view1 "o ( ! mo/ important ) :i* a seismologi/ has to deal4 ,we _c prev5t ! occurr5ce ( e>?quakes1 & unless we avoid e>?quake-%ak5 regions1 we h n ! means ( escap+ f !m4 ,:at we c d1 h[ev]1 is 9 "s degree to protect ourselves4 ,by /udy+ ! effects produc$ by e>?quakes ^u build+s ( diff]5t con/ruction & v>i\sly situat$1 we are taught h[ to avoid or at lea/ to mitigate calamities :i*1 9 c]ta9 regions ( ! _w1 are cont9ually repeat$4 ,! subject is an ext5sive "o1 & :at is "h said ab\t x mu/ be reg>d$ only z a contribution to ! "w ( future writ]s :o may give x ! att5tion x des]v$ly requires4 ,! ,de/ruction produc$ by ,e>?quakes is n irregul>4--,if we 7 sudd5ly plac$ among/ ! ru9s ( a l>ge city :i* _h be5 %att]$ by an e>?quake1 x is d\btful :e!r we %\ld at once recognise any law z to ! relative position ( ! masses ( dbris & ! g5]al de/ruction ) :i* we are surr\nd$4 ,! results ( obs]vation h1 h[ev]1 %[n u t1 among/ ! app>5tly *aotic ru9 produc$ by e>?quakes1 !re is 9 _m cases m or less law gov]n+ ! position ( bodies :i* h fall51 ! direction & position ( cracks 9 walls1 & ! v>i\s o!r ph5om5a :i* result f su* de/ructive di/urbances4 ,mallet1 at ! comm5cem5t ( 8 fir/ volume1 describ+ ! ,neapolitan e>?quake ( #aheg1 discusses ! g5]al effect produc$ by v>i\s %ocks ^u diff]5tly con/ruct$ build+s4 ,fir/ he %[s t1 if we h a rectangul> build+1 ! walls at "r angles to ! %ock w be m likely to be ov]?r[n ?an ^? :i* are p>allel to x4 ,exp]i5ce tea*es a simil> lesson4 ,?us ,d>w91 :5 speak+ ( ! e>?quake at ,concepcion 9 #ahce1bj tells u t ! t[n 0 built 9 ! usual ,spani% fa%ion1 ) all ! /reets runn+ at "r angles to ea* o!r4 ,"o set rang$ ,s4,w4 by ,w4 & ,n4,e4 by ,e4 & ! o!r ,n4,w4 by ,n4 & ,s4,e4 by ,s4 ,! walls 9 ! =m] direction c]ta9ly /ood bett] ?an ^? 9 ! latt]4 ,! undulations came f ! ,s4,w4 ,9 ,c>accas x is said t e h\se has its laga securo1 or safe side1 :]e ! inhabitants place _! fragile prop]ty4 ,?is laga securo is ! nor? side1 & x 0 *os5 because ab\t two out ( e ?ree de/ructive %ocks trav]s$ ! city f we/ to ea/1 s t ! walls 9 ^! sides ( a build+ h be5 /rick5 broadside on4#ba ,cracks 9 ,build+s4--,results l ! above come f de/ructive e>?quakes r ?an f movem5ts su* z ^? we h to deal ) ord9>ily4 ,:5 a build+ is subject$ to a slight movem5t x is assum$ t ! walls at "r angles to ! direction ( ! %ock move backw>ds & =w>ds z a :ole1 & !re is little or no t5d5cy = !m to be fractur$ at _! weak] p>ts1 ^! weak] p>ts be+ ^? ov] ! v>i\s op5+s4 ,! walls1 h[ev]1 :i* are p>allel to ! direction ( ! movem5t are1 s to speak1 ext5d$ & contract$ along _! l5g?1 & 9 consequ5ce !y may be expect$ to give way ov] ! v>i\s op5+s4 ,?is t5d5cy = ext5sion & contraction ( a wall along its l5g? may be suppos$1 = in/ance1 to be due to ! diff]5t portions ( a wall1 ow+ to diff]5ces 9 dim5sions & ela/icity1 hav+ diff]5t p]iods ( natural vibration1 or possibly = two portions ( a long l9e ( wall to be simultane\sly affect$ by portions ( waves 9 diff]5t phases4 ,z an illu/ration ( ! giv+ way ( a build+ 9 ! mann] "h sugge/$ we may take ! case ( a l>ge brick /ructure :i* 0 rec5tly be+ erect$ 9 ,tokio4 ,?is build+1 at ! "t ( ! e>?quake1 0 only "s f\rte5 or fifte5 feet above ! surface ( ! gr\nd4 ,! l5g? ( ! build+ /ret*$ f ,n4,w4 to ,s4,e41 & x 0 int]sect$ by _m walls at "r angles to ?is direction4 ,?r\gh all ! walls ( ?is build+ !re 7 _m ar*$ op5+s4 ,9 ! c5tral "p ( ! transv]se walls1 :i* walls 7 fully five feet 9 ?ickness1 ! ar*es :i* jo9$ !m toge!r 7 #d feet #d in*es 9 ?ickness4 ,! ar*es !re=e =m$ a comp>atively lightly con/ruct$ l9k betwe5 heavy masses ( brickwork4 ,on ,m>* #c1 #ahgi1 at #d4dc ,p4,m41 an e>?quake 0 felt ?r\gh\t ,tokio1 ! /r5g? ( :i*1 z judg$ by our feel+s1 0 above t ( an av]age %ock4 ,z regi/]$ by "o ( ,palmi]i's in/rum5ts1 x _h a direction ,s4,s4,w4 to ,n4,n4,e4 & an int5sity ( #aa4 ,on ! same day !re 7 sev]al small] %ocks hav+ ! same direction1 & ^! 7 succe$$ by o!rs on ! #i? ( ! mon?4 ,imm$iately aft] ^! %ak+s x 0 discov]$ t almo/ e ar* 9 ! int]nal walls ( ! build+ "h ref]r$ to _h be5 crack$ across ! cr[n 9 a direction ab\t ,n4 #dj ,w4 ,all ! o!r ar*es ( ! build+1 ( :i* !re 7 a great numb] 9 walls at "r angles to ! direction ( ! %ock1 7 f\nd n to h su/a9$ any injury4 ,to ?is /atem5t1 h[ev]1 !re 0 "o exception1 :i* 0 subsequ5tly prov$ to h be5 due to a settlem5t tak+ place4 ,aft] exam9+ ^! cracks ! only cause to :i* !y c\ld be attribut$ 0 ! s]ies ( %ak+s :i* !y _h j exp]i5c$4 ,x seem$ z if ! heavy walls "r & left ( ! ar*es _h be5 9 vibration )\t syn*ronism 9 _! p]iods1 & z a consequ5ce ! ar*es :i* connect$ !m _h be5 torn asund]4 ,al?\gh ! "t at :i* ! cracks 7 =m$ & ! peculi> positions 9 :i* !y 7 only to be f\nd po9t$ di/9ctly to _! orig91 to be c]ta9 t !y 7 n due to settlem5t ( ! f\ndations1 horizontal l9es 7 rul$ ^u ! brickwork & f "t to "t subsequ5tly obs]v$4 ,! po9ts to :i* ! v>i\s cracks ext5d$ 7 also m>k$ & obs]v$4 ,b5ea? ! walls z f\ndations !re 7 b$s ( concrete ab\t ?ree feet ?ick & ab\t t5 feet 9 wid?4 ,^! _h be5 "u ! pressure ( ! p>tially built walls = two ye>s be=e ! ar*es _h be5 put 94 ,z ^! f\ndations 7 unusually /rong1 be+ int5d$ to c>ry s v mu* great] weight ?an t to :i* !y _h be5 subject$1 if any settlem5t _h be5 detect$ x w\ld h be5 a matt] ( surprise4 ,"s weeks aft] ! =mation ( ^! cracks x 0 obs]v$ t !y gradually clos$4 ,?is 0 probably due to ! gradual fall+ inw>ds ( ! two brok5 portions ( ! ar*1 _! position :5 op5 be+ "o ( in/ability4 ,illu/ration3 ,,fig4 #af4--;,cracks 9 a corn] h\se1 ,belluno1 ,june #bi1 #ahgc 7,bittn]74 ,_h ?is build+ be5 m complete at ! "t ( ! %ock1 & ! heavy walls be5 ti$ toge!r at high] po9ts1 al?\gh ! ar*ways w\ld h be5 po9ts ( weakness1 x is q possible t fracture w\ld n h tak5 place4 ,?is illu/ration %[s u t :5 a build+ is %ak5 9 a def9ite direction !re w be "s rule z to ! positions 9 :i* fractures occur4 ,z ano!r example1 we may take ! obs]vations ( ,alex&] ,bittn] ^u ! build+s ( ,belluno aft] ! %ock ( ,june #bi1 #ahgc 7see ,beitrge zur ,k5ntniss des ,erdbeb5s von ,belluno am #bi ,juni1 #ahgc1 p4 #dj4 ,von ,alex&] ,bittn]4 ,aus dem ,,lxix4 ,b&e d] ,sitzungsb4 d] ,k4 ,akad4 d] ,wiss5s*41 ,,ii4 ,ab?41 ,april-,heft4 ,jahrg4 #ahgd74 ,speak+ g5]ally1 he rem>ks t #8,h\ses simil>ly situat$ h suff]$ 9 correspond+ walls & corn]s 9 a simil> mann]4 ,9 ,belluno !re is a c]ta9 k9d ( damage :i* is repeat$ ev]y:]e1 mak+ a peculi> sy/em ( splits 9 ! ,s4,w4 & ,n4,e4 corn]s ( ! h\ses4' ,?is is well %[n 9 ! accompany+ sket*1 :i* evid5tly illu/rates ! effect ( a %ock oblique to ! direction ( two walls at "r angles to ea* o!r4 ,illu/ration3 ,,fig4 #ag4--;,brick build+s 9 ,tokio1 %[+ fractures4 ,build+s 9 ,tokio4--,= ! purpose ( f9d+ out :at has be5 ! effect produc$ by e>?quakes ^u ! build+s ( ,tokio1 & at ! same "t = asc]ta9+ :e!r blocks ( build+s rang+ 9 diff]5t directions suff]$ to ! same ext5t1 ! au?or exam9$1 9 company ) ,mr4 ,josiah ,cond]1 a l>ge numb] ( =eign-built h\ses 9 ! di/rict ( ! ,g9za4 ,! *ief reason = *oos+ ?is 0 because x 0 ! only di/rict :]e a l>ge numb] ( simil> build+s c\ld be f\nd4 ,by exam9+ h\ses or build+s ( diff]5t con/ructions1 ! effects produc$ ^u !m by e>?quakes are v (t5 likely to %[ s _m diff]5ces t x becomes almo/ an impossibility to det]m9e :at ! g5]al effect has be5--unsymmetrical con/ruction involv+ unsymmetrical ru94 ,a numb] ( simil>ly con/ruct$ build+s 9 "o locality may be reg>d$ z a numb] ( seismographs1 ! effect ^u any "o ( !m be+ judg$ ( by ! av]age ( ! g5]al effect :i* has be5 produc$ ^u ! :ole4 ,! g5]al =m ( two ( ^! h\ses :i* 7 exam9$ is %[n 9 fig4 #ag4 ,9 ?is figure ! g5]al "* ( ! fractures :i* h be5 produc$ c also be se54 ,! h\ses are built ( brick1 & are 9 _m cases fac$ ) a ?9 coat ( :ite pla/]4 ,project+ f ! level ( ! upp] floor !re is a balcony front$ by a l[ balu/rade4 ,?is is support$ by small beams :i* at _! out] extremity are c>ri$ on a r[ ( cyl9drical columns4 ,?is =ms a cov]$ way 9 front ( ea* r[ ( h\ses4 ,! ro(s are cov]$ ) ?ick tiles4 ,x w be obs]v$ t ! ar*es ( ! upp] w9d[s spr+ %>ply f _! abutm5ts1 & at _! cr[n !y c>ry a heavy key-/one4 ,! l[] op5+s1 :i* h a span ( #i feet1 h evid5tly be5 con/ruct$ 9 imitation ( ! op5 front ( an ord9>y ,japanese h\se4 ,^! ar*ways curve out g5tly f _! abutm5ts4 ,! outside walls h a ?ickness ( #ac in*es4 ,! results obta9$ f a c>eful exam9ation ( #agd h\ses 9 /reets runn+ ,n4,e4 & #aef h\ses 9 /reets runn+ ,n4,w41 all ( ^! h\ses be+ simil>1 7 z foll[s3-- #a4 ,9 ! upp] w9d[s ne>ly all ! cracks ran f ! spr++1 :i* =m$ an angle ) ! abutm5t4 #b4 ,9 ! l[] ar*es1 :i* curv$ into ! abutm5ts1 n a s+le crack 0 obs]v$ at ! spr+way4 ,! cracks 9 ^! ar*es 7 ne> ! cr[n1 :]e beams project$ to c>ry ! balcony4 ,9 _m in/ances ! cracks proce$$ f su* beams1 ev5 if !re 7 no ar* b5ea?4 ,t cracks %\ld occur 9 peculi> positions1 z is "h indicat$1 is %[n 9 ! illu/rations :i* accompany ! acc\nts ( _m e>?quakes4 #c4 ,! h\ses :i* 7 mo/ crack$ 7 9 ! /reets runn+ p>allel to ! direction 9 :i* ! great] numb] & mo/ p[]ful set ( %ocks cross ! city4 ,! results %[$ t1 9 ord] to avoid ! effects ( small %ocks1 all walls conta9+ pr9cipal op5+s %\ld be plac$ z ne>ly z possible at "r angles to ! direction 9 :i* ! %ocks ( ! di/ricts usually travel4 ,! blank walls1 or ^? conta9+ unimportant op5+s1 w\ld !n be p>allel to ! direction ( ! %ocks--t is1 presum+ our build+ to be made up ( two sets ( walls at "r angles to ea* o!r4 ,ano!r po9t ( importance w\ld be to build ar*ways curv+ into ! support+ buttresses2 ! ar*ways ov] doors & w9d[s :i* we f9d 9 e>?quake c\ntries d n appe> to be 9 any way diff]5t f ^? :i* are built 9 c\ntries free f e>?quakes4 ,9 ! "o c\ntry ^! /ructures h simply to )/& v]tical pressures appli$ /atically2 9 ! o!r1 !y h to )/& m or less horizontal /resses1 appli$ sudd5ly4 ,relation ( ,de/ruction to ,e>?quake ,motion4--,! relations :i* exi/ betwe5 ! ov]turn+ & projection ( bodies & ! motion ( ! gr\nd h already be5 discuss$4 ,x may be int]e/+ to call att5tion to ! fact t 9 ! =mul %[+ ?ree relation%ips1 x 0 ! %ape r ?an ! weight ( a body :i* det]m9$ :e!r x %\ld be ov]turn$ or project$ by a motion at its base4 ,z an int]e/+ pro( t light bodies may be ov]turn$ z easily z heavy ones4 ,mallet ref]s to ! ov]turn+ ( sev]al l>ge hay/acks z "o ( ! results ( ! ,neapolitan e>?quake4 ,if masses ( mat]ial are displac$ or fractur$1 !n ,mallet rem>ks t ! maximum velocity w exce$ #b;gh1 :]e h is ! amplitude ( ! wave4 ,%\ld ! maximum velocity be less ?an ?is quantity1 ! masses :i* are act$ ^u w be simply rais$ & l[]$1 & !re w be no relative displacem5ts ev5 if ! em]g5ce ( ! wave be ne>ly or q v]tical4 ,:5 we get a v]tical wave act+ ^u an irregul> mass ( masonry1 ! heavi] portions ( ! masonry1 by _! in]tia1 t5d to desc5d relatively to ! rema9+ portions1 & 9 ?is way v]tical fissures w be produc$4 ,= ?is reason x w\ld n be advisable to use heavy mat]ials above ar*ways1 heavy ro(s1 or heavy floors4 ,! v]tical fissures1 ,mallet rem>ks1 w\ld h _! wide/ op5+ at ! base4 ,9 consid]+ cases ( fracture produc$ by e>?quake motion1 x mu/ be rememb]$ t ^! are due to /resses appli$ sudd5ly1 & t if ! same am\nt ( /ress _h be5 sl[ly appli$ to a build+1 fractures might n h occurr$4 ,if a di/urbance is horizontal1 & has a direction p>allel to ! l5g? ( a wall1 ! wall is c>ri$ =w>d at its f\ndations4 ,?is motion is oppos$ by ! in]tia ( ! upp] portion ( ! wall & ! v>i\s loads x c>ries4 ,! wall be+ ela/ic1 di/ortion takes place1 & cracks1 :i* are wide/ at ! top1 w be =m$4 ,9 a uni=m wall ! two mo/ prom95t fissures ought to be ne> ! ends4 ,if ! horizontal backw>d & =w>d movem5t has a direction oblique to ! plane ( ! wall1 ! wall w be ei!r ov]?r[n1 fractur$1 or h a triangul> fragm5t ?r[n (f t[>ds ! orig9 f ! end la/ rea*$4 ,%\ld ! wave em]ge /eeply1 diagonal fissures at "r angles to ! direction ( transit w be =m$1 or else triangul> pieces w be project$4 ,! accompany+ figures are r$uc$ f ,mallet's #8,acc\nt ( ! ,neapolitan ,e>?quake ( #aheg4' ,illu/ration3 ,,fig4 #ah4--;,ca!dral ,*ur*1 ,pot5za 7,mallet74 ,tak+ a b z ! g5]al direction ( ! fractures 9 fig4 #ah1 !n c d w repres5t ! direction 9 :i* ! %ock em]g$1 :i* is at an angle ( #bcbj to ! horizon4 ,x might be argu$ t ! direction ( ^! fractures 0 due to ! direction 9 :i* surface undulations _h travell$1 or to ! relative /r5g?s & proportions ( diff]5t portions ( ! build+4 ,! directions ( cracks 9 a build+ are und\bt$ly due to a complexity ( causes1 b = build+s situat$ 9 ! region ( %ock ! impulsive effect ( ! %ock is probably ! mo/ important function to be consid]$4 ,! me?od ( apply+ ! directions ( em]g5ce1 d$uc$ f obs]vations on fractures1 to det]m9e ! orig9 ( a di/urbance w be ref]r$ to 9 ,*apt] ,x4 ,illu/ration3 ,,fig4 #ai4--,! ,ca!dral1 ,pat]no 7,mallet74 ,neapolitan ,e>?quake ( #aheg4 ,mallet obs]v$ t1 al?\gh two ends ( a build+ might be ne>ly ! same1 ! fissures & jo9ts d n occur at equal di/ances f ! ends1 nor are !y equally op5$4 ,! end :]e ! jo9ts are ! mo/ op5$ is t :i* 0 fir/ act$ ^u1 & ?is ph5om5on may be suffici5tly well pron\nc$ to indicate ! direction 9 :i* we mu/ look to f9d ! orig9 ( a di/urbance4 ,among/ possible explanations = ?is disposition ( fractures 9 a wall4 ,mallet sugge/s t !y may be due to real diff]5ces 9 ! two semiphases ( ! wave ( %ock1 ! second semiphase be+ describ$ ) a some:at sl[] velocity ?an ! fir/4 ,?is1 x w be obs]v$1 is contr>y to ! indications ( seismographs4 ,fig4 #ai1 ( ! ca!dral at ,pat]no1 %[s ! effect ( a subnormal %ock /rik+ a wall obliquely & project+ "o ( its corn]s4 ,,measurem5ts ,,( ,,! ,,relative ,,motion ,,( ,,p>ts ,,( ,a ,,build+ ,,at ,,! ,,"t ,,( ,,an ,,e>?quake4 ,9 #ahhj a s]ies ( obs]vations 0 made 9 ,tokio to det]m9e :e!r at ! "t ( an e>?quake ! v>i\s p>ts ( ! ar*$ op5+s :i* we see 9 _m build+s syn*ronis$ 9 _! vibrations1 or1 = want ( syn*ronism1 7 caus$ to approa* & rec$e f ea* o!r4 ,! ar*es exp]im5t$ on 7 heavy brick ar*es =m+ ! two corridors ( ! ,imp]ial ,college ( ,eng9e]+4 ,! direction ( "o set ( ^! corridors is ,n4 #dj ,e4 & t ( ! o!r ,n4 #ej ,w4 ,! ?ickness ( ! walls 9 :i* ^! ar*es are plac$ is #a ft4 #aa 94 ,!y are built ( ,japanese bricks b\nd toge!r ) ord9>y lime4 ,! span ( ! ar*es is #h ft4 #c 941 & ! height ( ! ar* f ! spr++-l9e to ! cr[n #d ft4 #a 94 ,! height ( ! abutm5ts is #g ft4 #a 94 ,! v\ssoirs ( ! ar* are =m$ ( a light grey s(t volcanic rock1 & on _! faces %[ a dep? ( #ab in*es4 ,! wid? ( ! int]m$iate columns betwe5 ! ar*es is #d ft4 #f 94 ,to det]m9e :e!r at ! "t ( an e>?quake !re 0 any v>iation 9 ! dim5sions ( ^! ar*es1 a light /iff deal rod1 ab\t #b 94 by 94 9 cross section1 0 plac$ across ! spr++-l9e ( ! ar*4 ,"o end ( ?is 0 firmly fix$ to ! top ( "o abutm5t by means ( a spike2 on ! o!r end1 :i* 0 to indicate any horizontal movem5t if ! abutm5ts approa*$ ea* o!r1 !re 0 fix$ a po9t] made out ( a piece ( /eel wire4 ,?is re/$ on a piece ( smok$ glass fix$ to ! l$ge on :i* ! loose end ( ! rod 0 re/+4 ,if ! abutm5ts approa*$ or rec$$ f ea* o!r a l9e w\ld be drawn measur+ ! ext5t ( ! motion4 ,z a fur!r indication ( motion1 a second smok$ glass plate 0 fix$ on ! transv]se rod1 :i* plate 0 m>k$ on by a po9t] atta*$ to a v]tical rod hang+ d[n f ! cr[n ( ! ar*4 ,z a g5]al result ( ^! exp]im5ts x may be said t ! portions ( ! build+ :i* 7 exam9$ usually ei!r did n move at all1 or else !y practically syn*ronis$ 9 _! movem5ts4 ,:5 !y did move1 ! ext5t ( motion 0 small1 & ! small diff]5ces 9 movem5t :i* 7 obs]v$ 7 9 e probability f> )9 ! ela/ic limits ( ! /ructure4 ,obs]vations on ,cracks4--,to det]m9e :e!r ! walls ( a build+ :i* h once be5 crack$1 :5 subject$ to a s]ies ( %ocks1 simil> to ^? :i* !y exp]i5c$ be=e be+ crack$1 /ill cont9u$ to give way1 ! extremities ( a consid]able numb] ( cracks 9 ! ,n4,e4 end ( ! museum build+s ( ! ,eng9e]+ ,college 7 m>k$ ) p5cil4 ,al?\gh s9ce ! "t ( m>k+ !re _h be5 _m sev]e %ocks1 ^! cracks did n visibly ext5d4 ,^! m>ks 7 made on ! outside wall ( ! build+4 ,on ! inside1 "o ( ^! same cracks %[$ itself z a fissure ab\t in* 9 wid?4 ,across ?is crack a horizontal /eel wire po9t] 0 plac$4 ,"o end ( ?is wire 0 fix$ 9 ! wall2 ! o!r end1 :i* 0 po9t$1 re/$ on ! surface ( a smok$ glass plate plac$ on ! o!r side ( ! crack4 ,aft] small e>?quakes !re 0 no indication ( motion hav+ tak5 place1 b aft] a %ock on ,febru>y #ba1 z indicat$ by a l9e ^u ! smok$ glass plate1 x 0 se5 t ! sides ( ! crack _h approa*$ & rec$$ f ea* o!r ?r\gh a di/ance ( ab\t #a_/af in*4 ,by simil> contrivances plac$ on cracks 9 a neighb\r+ build+ exactly simil> results 7 obta9$1 namely1 t dur+ small e>?quakes ! two sides ( ! crack _h reta9$ _! relative positions1 b at ! "t ( a l>ge %ock ?is position _h be5 *ang$4 ,9 ?is build+ x 0 also obs]v$ t ! cracks 9 _m in/ances increas$ _! l5g?4 ,by atta*+ lev]s to ! end ( ! po9t]s to multiply any motion t might take place1 no d\bt ! indications w\ld be m frequ5t & m def9ite4 ,x w\ld also be easi] to note ! relative di/ances ( motion 9 two directions1 namely1 h[ f> ! cracks _h clos$ & h[ f> !y _h op5$4 ,z to :e!r motion w\ld occur or n1 mu* w\ld no d\bt dep5d ^u ! direction ( ! e>?quake4 ,prev5tion ( ,fractures4--,"o conclusion :i* may p]haps be drawn f ^! obs]vations is1 t a crack$ build+ at ! "t ( an e>?quake %[s a c]ta9 am\nt ( flexibility4 ,:e!r a build+ :i* _h be5 design$ ) cracks or jo9ts betwe5 ^? p>ts :i* 7 likely to h diff]5t p]iods ( vibration w\ld be m /able1 s f> z e>?quake %ak+s are conc]n$1 ?an a simil> build+ put up 9 an ord9>y mann]1 is a matt] to be decid$ by exp]im5t4 ,c]ta9ly "s ( ! cracks :i* h be5 exam9$ indicate t if !y _h n exi/$1 ! /ra9 ^u ! portion ( ! build+ :]e !y occur w\ld h be5 extremely great4 ,direction ( ,cracks4--,9 look+ at ! cracks produc$ by small e>?quakes x is int]e/+ to note ! mann] ( _! ext5sion4 ,! basem5ts ( ! build+s :i* h be5 mo/ c>efully exam9$ are1 = a height ( two or ?ree feet1 built ( l>ge rectangul> blocks ( a greyi%-col\r$ volcanic rock4 ,9 ^! p>ts ! cracks pass 9 & out betwe5 ! jo9ts ( ! /one1 indicat+ t ! /ones h evid5tly be5 /rong] ?an ! mort> :i* b\nd !m toge!r1 & z a consequ5ce ! latt] _h to give way4 ,above ?is basem5t :5 ! cracks ent] ! brickwork1 !y no long] exclusively conf9e !mselves to ! jo9ts1 b run 9 an irregul> l9e ?r\gh all !y meet )1 sometimes across ! bricks & sometimes ?r\gh ! mort> jo9ts4 ,9 places :]e !y h trav]s$ ! brickwork1 we c say t ! mort> has be5 /rong] ?an ! bricks4 ,?is trav]s+ ( ! bricks r ?an ! jo9ts is1 ,i ?9k1 ! g5]al rule = ! direction ( ! cracks 9 ! brickwork ( ,tokio build+s4 ,! ,pit* ( ,ro(s4--,f obs]vation ( ! effects produc$ by e>?quakes1 x appe>s to u t ! h\ses :i* lo/ ! great] numb] ( tiles appe> to be ^? ) ! /eepe/ pit*1 & ^? :]e ! tiles 7 simply laid ^u ! ro( & n 9 any mann] fa/5$ d[n4 ,x w\ld seem t de/ruction ( ?is sort might to a great ext5t be obviat$ by giv+ ! ro(s a less incl9ation & fix+ ! tiles ) nails4 ,x 0 also notic$ t ! greate/ di/urbance among/ ! tiles 0 ^u ! ridges ( ! ro(s4 ,de/ruction ( ?is sort might be ov]come by giv+ especial att5tion to ^! portions dur+ ! con/ruction ( ! ro(4 ,illu/ration3 ,,fig4 #bj4 ,,fig4 #ba4 ,relative ,position ( ,op5+s 9 ,walls4--,f :at has be5 said ab\t ! fractures 9 ! build+s ( ,tokio x w h be5 se5 t1 ) b few exceptions1 !y h all tak5 place above op5+s l doorways & w9d[s4 ,if ar*itecture dem&s t op5+s l ar*es %\ld be plac$ "o above ano!r 9 heavy walls ( ?is k9d1 z 9 fig4 #ag1 !re w be l9es ( weakness runn+ ?r\gh ! op5+s p>allel to ! dott$ l9es4 ,z ar*es are only int5d$ to resi/ v]tical ?ru/s1 special con/ruction mu/ be adopt$ to make !m /rong en\gh to resi/ horizontal pulls4 ,= in/ance1 a flat ar* w\ld (f] m resi/ance to horizontal pulls ?an an ar* put toge!r ) ord9>y v\ssoirs1 !re be+ 9 ! =m] case m friction to prev5t ! compon5t p>ts slid+ ov] ea* o!r4 ,or aga91 above ea* ar* an iron gird] or wood5 l9tel might be ins]t$ 9 ! brick or /one ar*4 ,x 0 sugge/$ to me by my colleague1 ,mr4 ,p]ry1 t ! be/ =m calculat$ to give a wall uni=m /r5g?1 w\ld be to build x s t ! op5+s ( ea* ti] w\ld occupy alt]nate positions1 t is to say1 along l9es p>allel to ! /ruts & ties ( a gird]4 ,9 ?is way we %\ld h our mat]ials s arrang$ t !y w\ld (f] ! same resi/ance to horizontal z to v]tical movem5ts4 ,su* a wall is %[n 9 fig4 #bj3 ! dott$ l9es runn+ ?r\gh ! op5+s1 & all simil> l9es p>allel to ! =m]1 repres5t+ l9es ( weakness4 ,if we comp>e ?is ) fig4 #ba1 we %all see t 9 ! case ( a horizontal movem5t a b or ( a v]tical movem5t c d1 we %\ld r expect to f9d fractures 9 a h\se built l fig4 #ba ?an 9 "o built l fig4 #bj4 ,if1 h[ev]1 ^! two build+s 7 %ak5 by a %ock :i* _h an angle ( em]g5ce ( ab\t #de 9 ! direction e f1 ! effects might be rev]s$4 ,usually1 h[ev]1 & always 9 a t[n l ,tokio :i* is visit$ by %ocks orig9at+ at a di/ance1 ! movem5ts are practically horizontal ones1 &1 !re=e1 build+s erect$ on ! pr9ciples illu/rat$ by fig4 #bj %\ld be mu* sup]ior1 s f> z resi/+ e>?quakes is conc]n$1 to build+s con/ruct$ 9 ! ord9>y mann]1 z 9 fig4 #ba4 ,fractures foll[+ a v]tical l9e ( weakness are %[n 9 ! accompany+ draw+1 fig4 #bb1 ( ! ,*ur* ( ,/4 ,augu/91 at ,manilla1 %att]$ by ! e>?quakes ( #ahhj4 ,! la/ ,h\se 9 a ,r[4--,:5 an e>?quake %ock ent]s a l9e ( build+s1 & proce$s 9 a direction co9cid5t ) t ( ! build+s1 we %\ld expect t ! la/ ( ^! h\ses1 be+ unsupport$ on "o side1 w\ld be 9 ! position ( ! la/ p]son 9 ,tyndall's r[ ( boys4 ,f ?is x w\ld seem t ! end h\se 9 a r[ w\ld %[ ! greate/ t5d5cy to fly away f its neighb\rs4 ,if ! la/ h\se /ood ^u ! edge ( a deep canal or a cliff1 !re w\ld be a lay] ( gr\nd1 equal 9 ?ickness to ! dep? ( ! canal or to ! height ( ! cliff1 z ! case may be1 :i* w\ld also be 9 a position to be ?r[n =w>d4 ,! effect :i* is sometimes produc$ ^u an end build+ is %[n 9 fig4 #bc1 :i* is tak5 f ! photograph ( a h\se %att]$ 9 #ahfh at ,san ,francisco4 ,illu/ration3 ,,fig4 #bb4--;,*ur* ( ,/4 ,augu/91 ,manilla4 ,e>?quakes ( ,july #ah-bj1 #ahhj4 ,! ,sw+ ( ,build+s4--,! di/ance ?r\gh :i* build+s are mov$ at ! "t ( an e>?quake dep5ds p>tly on _! con/ruction & p>tly on ! ext5t1 nature1 & duration ( ! movem5t communicat$ to !m at _! f\ndations4 ,by viol5t %ocks build+s may be completely ov]?r[n4 ,9 ! case ( small e>?quakes1 ! upp] portion ( a h\se may frequ5tly move ?r\gh a mu* great] di/ance ?an ! gr\nd at its f\ndation4 ,= in/ance1 dur+ ! ,yokohama e>?quake ( ,febru>y1 #ahhj1 :5 ! maximum amplitude ( ! e>?'s motion 0 probably "u ( an in*1 f ! sl[ sw+ ( long ,japanese pictures1 f ?ree to six feet 9 l5g?1 :i* oscillat$ backw>ds & =w>ds on ! wall1 x is v probable t ! ext5t ?r\gh :i* ! upp] portion ( h\ses mov$ 0 v consid]able4 ,9 "s in/ances ^! pictures seem to h swung z mu* z two feet1 & f ! mann] 9 :i* !y swung !y evid5tly syn*ronis$ ) ! natural sw+ ( ! h\se4 ,illu/ration3 ,,fig4 #bc4--,webb] ,h\se1 ,san ,francisco4 ,oct4 #ba1 #ahfh4 ,f ?is x w\ld seem t su* a h\se mu/ h rock$ f side to side "o foot out ( its normal p]p5dicul> position4 ,t ! motion 0 great is te/ifi$ by ne>ly all :o tri$ to /& at ! "t ( ! %ock1 x hav+ be5 impossible to walk /eadily across ! floor ( a room 9 an upp] /ory4 ,! h\ses "h ref]r$ to are ei!r ^? :i* are purely ,japanese1 or else ^? :i* are fram$ ( wood & built on ,european models1 a class ( build+ :i* is v common 9 ,tokio & ,yokohama4 ,p]ry & ,ayrton calculat$ ! p]iod ( a complete natural vibration ( diff]5t /ructures4 ,= a squ>e h\se ^: out] & inn] sections 7 respectively #cj & #bf feet1 & ^: height 0 #cj feet1 ! p]iod calculat$ w\ld be ab\t #jf second4 ,at ! "t ( ! above e>?quake _m h\ses seem to h mov$ l inv]t$ p5dulums4 ,on ! morn+ aft] ! %ock my neighb\r1 :o 0 liv+ up/airs 9 a tall wood5 h\se ) a tile ro(1 told me t he endeav\r$ to c\nt ! vibrations1 & 0 ( ! impression t to make a complete sw+ x took ab\t #b seconds4 ,assum+ n[ t ! di/ance ?r\gh :i* ! top ( a wood5 h\se mov$ 0 ab\t #a foot1 & ! numb] ( vibrations :i* x made p] second 0 ab\t #e1 !n ! greate/ velocity ( a po9t on ! top ( su* a h\se mu/ h be5 ab\t #f feet p] second4 ,mallet1 :o made obs]vations ^u ! vibrations ( v>i\s /ructures1 tells u t ,salisbury spire moves to & fro 9 a gale m ?an #c in*es4 ,a well-con/ruct$ brick & mort> wall1 #dj feet high & #a foot #f in*es ?ick1 0 obs]v$ to vibrate 9 a gale #b feet transv]sely be=e x fell4 ,an octagonal *imney ) a heavy granite capp+1 #afj feet high1 0 obs]v$ in/rum5tally to vibrate at ! top ne>ly #e in*es4#bb ,at ! "t ( a sev]e e>?quake x does n seem impossible b t a build+ may be swung completely ov]4 ,! accompany+ illu/ration1 fig4 #bd1 tak5 f a photograph1#bc app>5tly indicates a movem5t ( description4 ,illu/ration3 ,,fig4 #bd4--,/ud ,mill at ,hayw>ds1 ,cali=nia4 ,oct4 #ba1 #ahfh4 ,pr9ciple ( relative ,vibrational ,p]iod4--,if a la? or ?9 pole load$ at "o end ) a weight fix$ to ! gr\nd1 s z to /& v]tically1 be %ak5 by an e>?quake x w be caus$ to rock to & fro l an inv]t$ p5dulum4 ,! p]iod ( its sw+ w be *iefly dep5d5t on its dim5sions1 its ela/icity1 & its load4 ,9 a build+ we h to consid] ! vibration ( a numb] ( p>ts1 ! p]iods ( :i*1 if !y 7 indep5d5t ( ea* o!r1 w\ld be diff]5t4 ,on acc\nt ( ?is diff]5ce 9 p]iod1 :il/ "o portion ( a build+ is endeav\r+ to move t[>ds ! "r1 ano!r is pull+ t[>ds ! left1 &1 9 consequ5ce1 ei!r ! bonds :i* jo9 !m or else !y !mselves are /ra9$ or brok54 ,?is 0 /rik+ly illu/rat$ by _m ( ! *imneys 9 ! h\ses at ,yokohama1 :i* by ! e>?quake ( ,febru>y #bj1 #ahhj1 7 %orn (f j above ! ro(4 ,! *imneys 7 %afts ( brick1 & probably _h a sl[] p]iod ( vibration ?an ! ro( ?r\gh :i* !y pass$1 ?is latt] vibrat+ ) ! ma9 portion ( ! h\se1 :i* 0 fram$ ( wood4 ,a p>ticul>ly in/ructive example ( ?is k9d :i* came "u my notice is r\ghly sket*$ 9 fig4 #be4 ,illu/ration3 ,,fig4 #be4 ,?is is a *imney /&+ alone1 :i*1 = ! sake ( support1 0 /rapp$ by an iron b& to an adjo9+ build+4 ,x w\ld seem t at ! "t ( ! %ock1 ! build+ mov+ "o way & ! *imney ano!r1 ! sw+ ( ! heavy build+ gave ! *imney a %>p j]k & cut x (f4 ,! upp] portion1 be+ !n loose ^u ! l[] "p1 rotat$ "u ! influ5ce ( ! oscillations 9 mann] simil> to t 9 :i* grave/ones are rotat$4 ,mallet made obs]vations simil> to ^! 9 ,italy4 ,he tells u t a buttress may (t5 n h "t to transmit its /ability to a wall4 ,! wall & ! buttress h diff]5t p]iods ( vibration1 & !re=e !y ex]t impulsive actions on ea* o!r4 ,effects l ^! 7 /rik+ly obs]vable 9 _m ( ! rural ,italian *ur*es :]e ! belfry t[] is built into "o ( ! quo9s ( ! ma9 rectangul> build+4 ,n only h we to consid] ! relative vibrations ( ! v>i\s p>ts ( a build+ among/ !mselves1 b we h to consid] ! relation ( ! natural vibrations ( any "o ( !m or ! vibration ( ! build+ z a :ole1 ) reg>d to ! e>?1 ! vibrations ( :i* x mu/ be rememb]$ are n /rictly p]iodic4 ,"s ( ! m important results dep5d5t ^u ! pr9ciple ( #8relative vibrational p]iods' may be und]/ood f ! foll[+ exp]im5ts3-- ,illu/ration3 ,,fig4 #bf4 ,9 fig4 #bf ,a1 ,b1 & ,c are ?ree flat spr+s made out ( /rips ( bamboo1 & load$ at ! top ) pieces ( lead4 ,at ! bottom !y are fix$ into a piece ( bo>d ,d ,e1 & ! :ole re/s on a table ,f ,g4 ,! legs ( ?is table be+ slightly loose1 by plac+ ! f+]s on ! top ( x1 a quick %ort backw>d & =w>d movem5t c be produc$4 ,! weights on ,a & ,b are ! same1 b !y are l>g] ?an ! weight on ,c4 ,consequ5tly ! p]iods ( ,a & ,b are ! same1 b diff]5t to ! p]iod ( ,c4 ,! dim5sions ( ^! spr+s are z foll[s3 height1 #ah in*es2 ,a & ,b ea* c>ry weights equal to #cbj grammes1 & !y make "o vibration p] second2 ,c has a weight ( #aii grammes1 & makes #jge vibrations p] second4 ,fir/ ,exp]im5t4--,x w be f\nd t by giv+ ! table a g5tle backw>d & =w>d movem5t1 ! ext5t ( :i* movem5t may be s small t x w be difficult to detect x ) ! eye1 ei!r ,a & ,b may be made to oscillate viol5tly :il/ ,c rema9s /ill2 or vice v]s1 ,c may be caus$ to oscillate :il/ ,a & ,b rema9 /ill4 ,9 ! "o case ! p]iod ( %ak+ w h be5 syn*ron\s ) ! natural p]iod ( ,a & ,b1 :il/ 9 ! latt] x w h be5 syn*ron\s ) t ( ,c4 ,?is w\ld seem to %[ u t if ! natural p]iod ( vibration ( a h\se1 or ( p>ts ( x1 at any "t agree ) ! p]iod ( ! %ock1 x may be readily ?r[n into a /ate ( oscillation :i* w be dang]\s = its safety4 ,second ,exp]im5t4--,b9d ,a & ,b toge!r ) a /rip ( pap] pa/$ betwe5 !m4 7,! pap] us$ 0 ?ree-eigh?s ( an in* broad & w\ld c>ry a weight ( ne>ly ?ree p\nds47 ,if ! table be n[ %ak5 z be=e1 ,a & ,b w always h simil> movem5ts1 & t5d to rema9 at ! same di/ance ap>t1 & z a consequ5ce ! /rip ( pap] w n be brok54 ,f ?is exp]im5t x w\ld seem t s long z ! diff]5t portions ( a build+ h almo/ ! same p]iods ( vibration1 !re w be little or no /ra9 ^u ! tie-rods or :atev] contrivance may be us$ 9 connect+ ! diff]5t p>ts4 ,?ird ,exp]im5t4--,jo9 ,a & ,c1 or ,b & ,c ) a /rip ( pap] 9 a mann] simil> to ! la/ exp]im5t4 ,if ! table be n[ %ak5 ) a p]iod approximat+ ei!r to t ( ,a & ,b1 or ) t ( ,c1 ! pap] w be sudd5ly snapp$4 ,?is indicates t if we h diff]5t portions ( a build+ ( su* heights & ?icknesses t _! natural p]iods ( vibration are diff]5t1 ! /ra9 ^u ! portions :i* connect su* p>ts is enorm\s1 & x w\ld seem1 z a consequ5ce1 t ei!r ! vibrators !mselves1 or else _! connections1 mu/1 ( a necessity1 give way4 ,?is 0 v =cibly illu/rat$ 9 ! ,yokohama e>?quake ( ,febru>y #ahhj by ! knock+ ov] ( *imneys4 ,! p>ticul> case ( ! *imneys is1 h[ev]1 bett] illu/rat$ by ! next exp]im5t4 ,f\r? ,exp]im5t4--,take a little block ( wood ?ree-qu>t]s ( an in* squ>e & ab\t "o in* high1 & place x on ! top ( ,a1 ,b1 or ,c4 ,x w be f\nd t1 al?\gh ! spr+ on :i* x /&s is caus$ to sw+ backw>ds & =w>ds ?r\gh a di/ance ( ?ree in*es1 ! little block w reta9 its position4 ,?is little block we may reg>d z ! upp] "p ( a *imney /&+ on a vibrat+ /ack1 & we see t1 s long z ?is upp] portion is light1 x has no t5d5cy to fall4 ,fif? ,exp]im5t4--,repeat ! f\r? exp]im5t1 hav+ fir/ plac$ a small lead5 cap on ! top ( ! block repres5t+ ! *imney4 7,! cap us$ only weigh$ a few grammes47 ,:5 vibration comm5ces x w be f\nd t ! block quickly falls4 ,?is w\ld seem to indicate t *imneys ) heavy tops are m likely to fall ?an light ones4 ,six? ,exp]im5t4--,b9d ,a & ,b toge!r ) a /rip ( pap] & /& ! little block ^u ! top ( ei!r4 ,x w be f\nd t ! block w /& z 9 ! f\r? exp]im5t4 ,sev5? ,exp]im5t4--,b9d ,a & ,c1 or ,b & ,c toge!r1 & place ! block ^u ! top ( ei!r ( !m4 ,:5 vibration comm5ces1 al?\gh ! pap] may n be brok51 ! little block w quickly fall4 ,eigh? ,exp]im5t4--,take two p5cils or pieces ( glass tube & place !m "u ! bo>d ,d ,e4 ,if ! table ,f ,g be n[ %ak5 9 ! direction ,d ,e1 x w be f\nd t ! spr+s w n vibrate4 ,9 a simil> mann] if a h\se or portion ( a h\se 7 c>ri$ on balls or roll]s1 z has already be5 sugge/$1 x w\ld seem t ! h\se might be sav$ f mu* vibration4 ,n9? ,exp]im5t4--,set any ( ! spr+s 9 viol5t vibration by g5tly %ak+ ,d ,e in/ead ( ! table1 & !n sudd5ly cease ! actuat+ motion4 ,x w be obs]v$ t at ! mom5t ( cessation ! bo>d & ! spr+s w h a sudd5 & v decid$ motion ( translation 9 ! same direction z t 9 :i* ! spr+s 7 la/ mov+1 & al?\gh ! spr+s 7 at ! "t sw++ ?r\gh a consid]able arc1 all motion w sudd5ly cease4 ,?is %[s1 t if a h\se is 9 a /ate ( vibration ! /ra9 at ! f\ndations mu/ be v great4 ,x w\ld n be difficult to devise o!r exp]im5ts to illu/rate o!r ph5om5a connect$ ) ! pr9ciple ( relative vibrational p]iods1 b ^! may p]haps be suffici5t to %[ to ^? :o h n consid]$ ?is matt] its great importance 9 ! con/ruction ( build+s4 ,p]haps ! great] portion ( :at is "h said may by _m be reg>d$ z self-evid5t truisms h>dly wor? ! tr\ble ( demon/ration4 ,_! importance1 h[ev]1 seems to be s great t ,i hope t _! discussion has n be5 altoge!r out ( place4 ,i may rem>k t 9 ! rebuild+ ( *imneys 9 ,yokohama ! pr9ciples "h enunciat$ 7 tak5 advantage ( by all[+ ! *imneys to pass freely ?r\gh ! ro(s )\t com+ 9 contact ) any ( ! ma9 timb]s4 ,9 putt+ up build+s to resi/ ! effects ( an e>?quake1 besides ! idea ( mak+ ev]y?+ /rong because ! e>?quake is /rong1 !re are sev]al pr9ciples :i*1 l ! "o j enunciat$1 might advantage\sly be foll[$ :i* z yet appe> to h receiv$ b little att5tion4 ,,*apt] ,,vii4 ,,effects ,,produc$ ,,^u ,,build+s 7cont9u$74 ,types ( build+s us$ 9 e>?quake c\ntries--,9 ,japan1 9 ,italy1 9 ,s\? ,am]ica1 9 ,c>accas--,typical h\ses = e>?quake c\ntries--,de/ruction due to ! nature ( und]ly+ rocks--,! sw+ ( m\nta9s--,want ( support on ! face ( hills--,e>?quake %ad[s--,de/ruction due to ! int]f]5ce ( waves--,e>?quake bridges--,examples ( e>?quake effects--,protection ( build+s--,g5]al conclusions4 ,types ( build+s us$ 9 e>?quake c\ntries4--,9 ,japan !re are excell5t opportunities ( /udy+ v>i\s types ( build+s4 ,! ,japanese types1 ( c\rse1 =m ! majority ( ! build+s4 ,! ord9>y ,japanese h\se consi/s ( a light framework ( #d or #e in* scantl+1 built toge!r )\t /ruts or ties1 all ! timb]s cross+ ea* o!r at "r angles4 ,! spaces are fill$ 9 ) wattle-"w ( bamboo1 & ?is is pla/]$ ov] ) mud4 ,?is con/ruction /&s on ! top ( a r[ ( b\ld]s or ( squ>e /ones1 driv5 into ! surface soil to a di/ance v>y+ f a few in*es to a foot4 ,! :ole arrangem5t is s light t x is n an uncommon ?+ to see a l>ge h\se roll$ along f "o position to ano!r on wood5 roll]s4 ,9 build+s su* z ^! aft] a s]ies ( small e>?quake %ocks1 we c\ld h>dly expect to f9d m fractures ?an 9 a wick] basket4 ,! l>g] build+s1 su* z temples & pagodas1 are also built ( timb]4 ,^! are built up ( su* a multitude ( pieces & fram$ toge!r 9 su* an intricate mann] t !y also are capable ( yield+ 9 all directions4 ,! ,european build+s are1 ( c\rse1 made ( brick & /one ) mort> jo9ts4 ,"s ( ^!1 z ! build+s ( ! ,g9za 9 ,tokio1 are n design$ = great /r5g?4 ,on ! o!r h&1 o!rs h ?ick & massive walls & are equal 9 /r5g? to ^? we f9d 9 ,europe4 ,! ?ird type ( build+s are ^? :i* are built 9 blocks2 & ^! blocks be+ b\nd toge!r ) iron rods trav]s+ ! walls 9 v>i\s directions are especially design$ to )/& e>?quakes4 ,a sy/em some:at simil> to ?is has be5 pat5t$ 9 ,am]ica1 & examples ( ^! s-call$ e>?quake-pro( build+s are to be f\nd 9 ,san ,francisco4 ,speak+ ( ,japanese build+s1 ,mr4 ,r4 ,h4 ,brunton1 :o has devot$ especial att5tion to !m says t1#bd #8to imag9e t slight build+s1 su* z are se5 "h 7i4e4 9 ,japan71 are ! be/ calculat$ to )/& an e>?quake %ock is an error ( ! mo/ palpable k9d4' ,aft] describ+ ! con/ruction ( a ,japanese h\se 9 pretty mu* ! same t]ms z we h us$1 he says #8t ) its unnecess>ily heavy ro( & weak framework x is a /ructure ( all o!rs ! wor/ adapt$ to )/& a heavy %ock4' ,he tells u1 fur!r1 t ^! views are su/a9$ by ! true/ pr9ciples ( me*anics4 ,9 ord] to r5d] build+s to "s ext5t pro( aga9/ e>?quakes1 "s ( ! heavy ro(s 9 ,tokio h be5 s con/ruct$ t !y are capable ( slid+ on ! walls4 ,mr4 ,brunton m5tions a design = a h\se1 ! upp] "p ( :i* is to re/ on balls1 :i* roll on inv]t$ cups fix$ on ! l[] "p ( ! build+1 :i* is to be firmly emb$d$ 9 ! e>?4 ,a simil> design 01 at ! sugge/ion ( ,mallet1 us$ to support ! tables c>ry+ ! app>atus ( "s ( ! ligh?\ses erect$ 9 ,japan by ,mr4 ,brunton4 ,! v exi/5ce ( ^! designs seems to indicate t ! ord9>y ,european h\se1 h[ev] solidly & /rongly x may be built1 is n suffici5t to meet ! conditions impos$ ^u x4 ,:at is requir$1 is some?+ t w give way--an approximation to ! timb] frame ( a ,japanese h\se1 s /rongly condemn$ by ,mr4 ,brunton & o!rs4 ,! crucial te/ ( ! value ( ! ,japanese /ructure1 z comp>$ ) ! mod]n build+s ( brick & /one1 is und\bt$ly to be f\nd by an appeal to ! build+s !mselves4 ,s f> z my own exp]i5ce has gone1 ,i mu/ say t ,i h nev] se5 any signs 9 ! ,japanese timb] build+s :i* c\ld be attribut$ to ! effects ( e>?quakes1 & ,8 ,excell5cy ,yamao ,yozo1 ,vice ,m9i/] ( ,public ,works1 :o has made ! /udy ( ! build+s ( ,japan a speciality1 told me t none ( ! temples & palaces1 al?\gh _m ( !m are sev]al c5turies old1 & al?\gh !y h be5 %ak5 by small e>?quakes & also by _m sev]e ones1 %[ any signs ( hav+ suff]$4 ,! greate/ damage wr\ght by l>ge e>?quakes appe>s to h result$ f ! influx ( l>ge waves or f fires4 ,9 e case :]e an e>?quake has be5 accompani$ by great de/ruction1 by consult+ ! books describ+ ! same1 x c be se51 f ! illu/rations 9 ^! books portray+ conflagrations1 t ?is de/ruction 0 *iefly due to fire4 ,:5 we rememb] t ne>ly all ,japanese h\ses are con/ruct$ ( mat]ials t are readily inflammable1 x is n h>d to imag9e h[ de/ruction ( ?is k9d has come ab\t4 ,to a ,japanese1 liv+ z he does 9 a h\se :i* has be5 comp>$ to a t9d]-box1 fire is "o ( 8 greate/ enemies1 & 9 a city l ,tokio x is n at all uncommon to see dur+ ! w9t] mon?s _m fires :i* sweep away f #ajj to #ejj h\ses4 ,9 "o w9t] ,i 0 a spectator ( ?ree fires1 ea* ( :i* 0 said to h de/roy$ upw>ds ( #aj1jjj h\ses4 ,al?\gh x w\ld appe> t ! small] e>?quakes ( ,japan produce no visible effect ^u ! native build+s1 x is nev]!less probable t small effects may h be5 produc$1 ! obs]vation ( :i* is r5d]$ difficult by ! nature ( ! /ructure4 ,if we look at build+s ( =eign con/ruction1 by :i* are meant build+s ( brick & /one1 ! picture be=e u is q diff]5t1 & ev]y:]e ! effects ( e>?quakes are palpable ev5 to ! mo/ casual obs]v]4 ,( ^! effects num]\s examples h already be5 giv54 ,n only are ^! build+s damag$ by ! crack+ ( walls & ! ov]turn+ ( *imneys1 b !y also appe> to be affect$ int]nally4 ,= in/ance1 9 ! timb]s ( ! ro( ( ! museum atta*$ to ! ,imp]ial ,college ( ,eng9e]+ 9 ,tokio1 !re are a numb] ( diagonal faces act+ z /ruts or ties int5d$ to prev5t m or less horizontal movem5ts tak+ place4 ,^? :i* are rigidly jo9$ toge!r ) bolts & angle irons h app>5tly suff]$ f _! rigidity1 be+ twi/$ & b5t into v>i\s =ms4 ,! build+s 9 ,tokio1 :i* are /rongly put toge!r1 be+ especially design$ to )/& e>?quakes1 appe> to h suff]$ b little4 ,i "k only "o example :i* at ! "t ( ! sev]e %ock ( #ahhj _h sev]al ( its *imneys damag$4 ,! ord9>y h\ses 9 ,italy1 ?\gh built ( /one & mort>1 are b poorly put toge!r1 &1 z ,mallet has rem>k$1 are 9 no way adapt$ to )/& ! frightful %ak+s to :i* !y are subject$ f "t to "t4 ,9 ! l>ge t[ns1 l ,naples1 ,rome1 & ,flor5ce1 :]e happily e>?quakes are ( r>e occurr5ce1 al?\gh ! build+ may be bett] ?an t f\nd 9 ! c\ntry1 ! height ( ! h\ses & ! n>r[ness ( ! /reets are suffici5t to create a %udd]1 :5 we ?9k ( ! possibility ( ! occurr5ce ( a mod]ately sev]e e>?quake4 ,9 ,s\? ,am]ica1 al?\gh _m build+s are built ) brick & /one1 ! ord9>y h\ses1 & ev5 ! l>g] edifices1 are specially built to )/& e>?quakes4 ,9 ,mr4 ,james ,d\glas's acc\nt ( a #8,j\rney ,along ! ,we/ ,coa/ ( ,s\? ,am]ica1' we read ! foll[+#be3 #8,! *>act]i/ic build+ mat]ial ( ,guayaquil is bamboo1 :i* gr[s to _m in*es 9 ?ickness1 & :i*1 :5 cut p>tially ?r\gh longitud9ally at di/ances ( an in* or s1 & once q ?r\gh1 c be op5$ out into f9e ela/ic bo>ds ( s]viceable wid?4 ,h\ses1 & ev5 *ur*es1 ( a c]ta9 primitive beauty are built ( su* re$s1 s b\nd toge!r ) cords t few nails ent] into ! con/ruction1 & :i*1 !re=e1 yield s readily to ! contortions ( ! e>? dur+ an e>?quake z to be comp>atively safe4' ,"h we h a h\se1 :i*1 s f> z e>?quakes are conc]n$1 is an exagg]at$ example ( ! pr9ciples :i* are foll[$ 9 ! con/ruction ( an ord9>y ,japanese dwell+4 ,ano!r plan adopt$ 9 ,s\? ,am]ica c be ga!r$ f ! same au?or's writ+s ^u ,lima1 ab\t :i* he says1 #8,to build high h\ses w\ld be to erect /ructures = ! fir/ e>?quake to make sport (1 &1 !re=e1 9 ord] to obta9 space1 safety1 & com=t1 ! h\ses ( ! weal?y surr\nd c\rt aft] c\rt1 fill$ ) fl[]s1 & cool$ ) f\nta9s1 connect$ "o ) ano!r ) wide passages :i* give a vi/a f g>d5 to g>d54' ,hi/ory w\ld indicate t h\ses ( ?is type h be5 arriv$ at z ! results ( exp]i5ce1 = x is said t :5 ! inhabitants ( ,s\? ,am]ica fir/ saw ! ,spani>ds build+ tall h\ses1 !y told !m !y 7 build+ _! own sepul*res4#bf ,9 ,jamaica1 we f9d t ev5 z e>ly z #afib exp]i5ce _h taught ! ,spani>ds to con/ruct l[ h\ses1 :i* )/ood %ak+s bett] ?an ! tall ones4#bg ,9 ,c>accas1 :i* has be5 call$ ! city ( e>?quakes1 x is said t ! e>?quakes cause an av]age ye>ly damage am\nt+ to ! equival5t ( a p] capita tax ( f\r doll>s4 ,to r$uce ?is impo/ to a m9imum mu* att5tion is paid to con/ruction4 #8,project+ basem5t corn]s 7giv+ ! h\se a slightly pyramidal appe>ance7 h be5 f\nd bett] ?an absolutely p]p5dicul> walls2 mortis$ corn]-/ones & ro( beams h sav$ _m lives :5 ! c5tral walls h split f top to bottom2 vaults & key-/one ar*es1 no matt] h[ massive1 are m p]il\s ?an common wood5 l9tels1 & !re are n _m isolat$ build+s 9 ! city4 ,9 _m /reets broad iron gird]s1 rivet$ to ! wall1 ab\t a foot above ! h\se door1 run f h\se to h\se along ! front ( an entire squ>e4 ,turret-l brick *imneys1 ) iron top ornam5ts1 w\ld expose ! ar*itect to ! v5geance ( an excit$ mob2 ! ro(s are flat1 or flat t]rac$2 ! *imney flues t]m9ate ne> ! eaves 9 a p]=at$ lid4'#bh ,typical h\ses = e>?quake c\ntries4--,f :at has n[ be5 said ab\t ! diff]5t build+s f\nd 9 e>?quake c\ntries1 x w be se5 t if we wi% to put up a build+ able to )/& a sev]e %ak+1 we h be=e u /ructures ( two types4 ,"o ( ^! types may be comp>$ ) a /eel box1 :i*1 ev5 7 x roll$ d[n a high m\nta91 w\ld suff] b little damage2 & ! o!r1 ) a wick] basket1 :i* w\ld equally )/& s sev]e a te/4 ,bo? ( ^! types may be1 to "s ext5t1 protect$ by plac+ !m ^u a loose f\ndation1 s t b little mom5tum ent]s !m at _! base4 ,"o sugge/ion is to place a build+ ^u iron balls4 ,ano!r me?od w\ld be to place !m ^u two sets ( roll]s1 "o set re/+ ^u ! o!r set at "r angles4 ,! ,japanese1 we h se51 place _! h\ses on r\nd /ones4 ,! solid type ( build+ is exp5sive1 & c only be approa*$ p>tially1 :il/ ! latt] is *eap1 & c be approa*$ closely4 ,9 ! case ( a solid build+ x w\ld be a m difficult matt] to support x ^u a movable f\ndation ?an 9 ! case ( a light framework4 ,su* a build+ is usually firmly fix$ on ! gr\nd1 & consequ5tly at ! "t ( an e>?quake1 z has already be5 %[n by exp]im5t1 mu/ be subject$ to /resses :i* are v great4 ,9 consequ5ce also ( ! great] weight ( ! solid /ructure1 m mom5tum w ent] x at its base ?an 9 ! case ( ! light /ructure4 ,also1 we mu/ rememb] t ! rigidity fav\rs ! transmission ( mom5tum1 & ) rigid walls we are likely to h ornam5ts1 cop+-/ones1 & ! comp>atively fre] portions =m+ ! upp] "p ( a build+ displac$2 :il/1 ) flexible walls absorb+ mom5tum 9 ! friction ( _! v>i\s p>ts1 su* di/urbances w\ld n be s likely4 ,mr4 ,t4 ,ronaldson1 ref]r+ to ?is1 says1 t 9 #ahfh1 at ,san ,francisco1 ! ornam5tal /one "w 9 /one & cem5t build+s 0 ?r[n f its position1 :il/ simil> ornam5ts 9 neighb\r+ brick build+s /ood4 ,to r$uce ! top weight ( a build+1 holl[ bricks might be employ$4 ,to r5d] a build+ m homog5e\s & ela/ic1 ! ?ickness ( bricks might be r$uc$4 ,inasmu* z ! ela/icity ( brick & timb] are s diff]5t1 ! two ought to be employ$ sep>ately4 ,= int]nal decorations pla/] m\ld+s might be replac$ by papi] m* & c>ton-pi]re1 ! ela/ic yield+ ( :i* is comp>atively great4#bi ,h\ses1 :e!r ( brick & /one1 or ( timb]1 ought to be broad & l[1 & ! /reets ?ree or f\r times z wide z ! h\ses4 ,! flatt] ! ro(s ! bett]4 ,"o ( ! safe/ h\ses = an e>?quake c\ntry w\ld probably be a "o-/ori$ /rongly fram$ timb] h\se1 ) a light flatti% ro( made ( %+les or %eet-iron1 ! :ole re/+ on a quantity ( small ca/-iron balls c>ri$ on flat plates b$d$ 9 ! f\ndations4 ,! *imneys might be made ( %eet-iron c>ri$ ?r\gh holes free ( ! ro(4 ,! ornam5tation ought to be ( light mat]ials4 ,at ! "t ( sev]e e>?quakes _m p]sons seek refuge f _! h\ses by leav+ !m4 ,9 ?is case accid5ts frequ5tly happ5 f ! fall+ ( bricks & tiles4 ,o!rs ru% to ! doorways & /& b5ea? ! l9tels4 ,p]sons ) :om ! au?or has conv]s$ h sugge/$ t /rongly con/ruct$ tables & b$/eads 9 _! rooms w\ld give protection4 ,to see p]sons d>t+ b5ea? tables & b$/eads w\ld und\bt$ly give rise to humiliat+ & ludicr\s exhibitions4 ,?is latt] idea is n )\t a value1 & mo/ c]ta9ly1 if appli$ 9 h\ses ( ! type describ$1 w\ld be valuable4 ,! great dang] ( fire may p>tially be obviat$ by3 ! use ( #8e>?quake lamps1' :i* are s con/ruct$ t be=e !y ov]turn !y are ext+ui%$4 ,x is said t 9 ,s\? ,am]ica "s ( ! inhabitants are ready at any mom5t to seek refuge 9 ! /reets1 & !y h coats prep>$1 /ock$ ) provisions &2 o!r necess>ies1 :i*1 if occasion dem&s1 w enable !m to sp5d ! night 9 ! op5 air4 ,^! coats1 call$ #8e>?quake coats1' might also1 ) prop]ly con/ruct$ h\ses1 be r5d]$ unnecess>y4 ,de/ruction due to ! nature ( ! und]ly+ rocks4--,t ! nature ( ! gr\nd on :i* a build+ /&s is intimately relat$ ) ! sev]ity ( ! bl[ x receives is a fact :i* has (t5 be5 demon/rat$4 ,"o cause ( de/ruction is due to plac+ a build+ on f\ndations :i* are capable ( receiv+ ! full effects ( a %ock1 & transmitt+ x to ! build+s /&+ on !m4 ,= in/ance1 ! reason :y a s(t b$ might possibly make a good f\ndation1 is1 z has be5 po9t$ out by ,messrs4 ,p]ry & ,ayrton1 because ! "t ( transmission ( mom5tum is increas$2 9 fact1 ! s(t b$ is v l a piece ( wood int]pos$ betwe5 a nail & ! bl[s ( a hamm]--x l5g!ns ! duration ( impact4 ,= ?is reason we are told t a quak+ bog w make a good f\ndation4 ,:5 a %ock ent]s loose mat]ials its waves w be m cr[d$1 & x is possible t a l9e ( build+s may re/ on m ?an "o wave dur+ a %ock4 ,!re are _m examples on record ( ! /ability ( build+s :i* re/$ on b$s ( p>ticul> mat]ial at ! "t ( de/ructive e>?quakes4 ,z ! obs]vations :i* h be5 made by v>i\s writ]s on ?is subject appe> to po9t 9 a contr>y direction1 ,i give ! foll[+ examples3-- ,9 ! great ,jamaica e>?quake ( #afib1 ! portions ( ,port ,royal :i* rema9$ /&+ 7 situat$ on a compact lime/one f\ndation2 :il/ ^? on s& & gravel 7 de/roy$ 7#8,geological ,obs]v]1' p4 #dbf74 ,aga91 on p4 #adh ( ! same "w1 we read1 #8,accord+ to ! obs]vations made at ,lisbon1 9 #agcg1 by ,mr4 ,%>pe1 ! de/roy+ effects ( ?is e>?quake 7 conf9$ to ! t]ti>y /rata1 & 7 mo/ viol5t on ! blue clay1 on :i* ! l[] "p ( ! city is con/ruct$4 ,n a build+ on ! second>y lime/one or on ! basalt 0 injur$4' ,9 ! great e>?quakes ( ,mess9a1 ^? portions ( ! t[n situat$ on alluvium1 ne> ! sea1 7 de/roy$1 :il/ ! high p>ts ( ! t[n1 on granite1 did n suff] s mu*4 ,simil> obs]vations 7 made 9 ,calabria1 :5 di/ricts consi/+ ( gravel1 s&1 & clay became1 by ! %ak+1 almo/ unrecognisable1 :il/ ! surr\nd+ hills ( slate & granite 7 b little alt]$4 ,at ,san ,francisco1 9 #ahfh1 ! *ief de/ruction 0 9 ! alluvium & made gr\nd4 ,at ,talcahuano1 9 #ahce1 ! only h\ses :i* escap$ 7 ! build+s /&+ on rocky gr\nd2 all ^? re/+ on s&y soil 7 de/roy$4 ,f ! results ( obs]vations l ^!1 x w\ld seem ! h>d] rocks =m bett] f\ndations ?an ! s(t] ones4 ,! explanation ( ?is1 9 _m cases1 appe>s to lie 9 ! fact t ! s(t /rata 7 9 a /ate ( un/able equilibrium1 & by %ak+1 !y 7 caus$ to settle4 ,obs]vations l ! foll[+1 h[ev]1 po9t out ano!r reason :y s(t /rata may sometimes af=d a bad f\ndation4 #8,humboldt obs]v$ t ! ,cordill]as1 compos$ ( gneiss & mica-slate1 & ! c\ntry imm$iately at _! foot1 7 m %ak5 ?an ! pla9s4'#cj #8,"s writ]s h ass]t$ t ! wave-l movem5ts 7( ! ,calabrian e>?quake 9 #aghc7 :i* 7 propagat$ ?r\gh rec5t /rata f we/ to ea/1 became v viol5t :5 !y rea*$ ! po9t ( junction ) ! granite1 z if a reaction 0 produc$ :5 ! undulatory movem5t ( ! s(t /rata 0 sudd5ly arre/$ by ! m solid rocks4' ,dolomieu :5 speak+ ( ?is e>?quake says1 ! usual effect #80 to disconnect f ! sides ( ! ,ap5n9es all ^? masses 7( s& & clay7 :i* ei!r _h n suffici5t bases = _! bulk1 or :i* 7 support$ only by lat]al adh]5ce4' ,^! int5sifi$ actions tak+ place at & ne> to l9es ( junction betwe5 dissimil> /rata is probably due to ! ph5om5a ( reflection & refraction4 ,:5 ref]r+ to ! "q z to :e!r build+s situat$ on loose mat]ials suff]$ m or less ?an ^? on solid rocks1 ,mallet1 9 8 description ( ! ,neapolitan e>?quake ( #aheg1 rem>ks3 #8,we h 9 ?is e>?quake1 t[ns su* z ,sapon>a & ,viggiano1 situat$ ^u solid lime/one1 totally pro/rat$2 & we h o!rs su* z ,montem>ro1 to a great ext5t bas$ ^u loose clays1 totally levell$4 ,we h examples ( almo/ complete immunity 9 places on pla9s ( deep clay z t ( ,viscolione1 & 9 places on solid lime/one1 l ,ca/elluccio1 or p]*$ on m\nta9 tops l ,pet9a4'#ca ,aft] read+ ! above1 we see t ! probable reason :y1 9 sev]al cases1 b$s ( s(t mat]ials h n made good f\ndations1 consi/s 9 ! fact t !y h ei!r be5 ( small ext5t or else h be5 obs]v$ only 9 ! neighb\rhood ( l9es :i* divid$ !m f o!r =mations1 :i* l9es are always ^? ( great di/urbances4 ,at ! end ( 8 description ( ! ,neapolitan e>?quake ( #aheg1 ,mallet says t m build+s 7 de/roy$ on ! rock ?an on ! loose clay4 ,?is1 h[ev]1 he rem>ks1 is h>dly a fact f :i* we c draw any valuable d$uctions1 because x s happ5$ t m build+s 7 con/ruct$ on ! hills ?an on ! loose gr\nd4#a ,pr(essor ,d4 ,s4 ,m>t91 writ+ on ! e>?quake ( ,new ,engl& 9 #ahgd1 rem>ks t 9 ,long ,isl& ! %ock 0 felt :]e !re 0 gneiss betwe5 ! drift4 ,ar\nd portions to ! ea/ ! obs]vations 7 few & f> betwe54 ,he also rem>ks t g5]ally ! %ocks 7 felt m /rongly & frequ5tly on rocky ?an on s(t gr\nd4#cb ,f ^! examples1 x w\ld appe> t ! h>d gr\nd1 :i* usually means ! hills1 =ms a bett] f\ndation ?an ! s(t] gr\nd1 :i* is usually to be f\nd 9 ! valleys & pla9s4 ,o!r examples1 h[ev]1 po9t to a diff]5t conclusion4 ,= in/ance1 a civil eng9e]1 writ+ ab\t ! ,new ,zeal& e>?quake ( #ahee1 :5 all ! brick build+s 9 ,well+ton 7 ov]?r[n1 says t #8x 0 mo/ viol5t on ! sides ( ! hills at ^? places1 & lea/ s 9 ! c5tre ( ! alluvial pla9s4'#cc ,9 ?is example x mu/ be notic$ t ! s(t alluvium "h ref]r$ to 0 ( l>ge ext5t1 & n loose mat]ial re/+ on ! flanks ( rocks1 f :i* x 0 likely to be %ak5 d[n1 z 9 mo/ ( ! previ\s examples4 ,! results ( my own obs]vations on ?is subject po9t z mu* 9 "o direction z 9 ! o!r4 ,9 ,tokio1 f in/rum5tal obs]vations ^u ! slopes & tops ( hills1 ! di/urbance appe>s to be v mu* less ?an x is 9 ! pla9s4 ,?us1 at my h\se1 situat$ on ! slope ( a hill ab\t #ajj feet 9 height1 = ! e>?quake ( ,m>* #aa1 #ahhb1 ,i obta9$ a maximum amplitude ( motion ( f ?ree to f\r millimtres only1 :il/ ,pr(essor ,ew+1 ) a simil> in/rum5t1 situat$ on ! level gr\nd at ab\t a mile di/ant1 f\nd a motion ( fully sev5 millimtres4 ,?is calculation has be5 confirm$ by obs]vations on o!r e>?quakes4 ,?us1 = in/ance1 9 ! de/ructive e>?quake ( #ahee1 :5 a l>ge portion ( ,tokio 0 deva/at$1 x 0 a fact1 rem>k$ by _m1 t ! di/urbance 0 mo/ sev]e on ! l[ gr\nd & 9 ! valleys1 :il/ on ! hills ! %ock _h be5 comp>atively weak4 ,z ano!r illu/ration1 ,i may m5tion t )9 ?ree-qu>t]s ( a mile f my h\se 9 ,tokio !re is a pr9ce's resid5ce :i* has s great a reputation = ! sev]ity ( ! %ak+s x receives t its m>ketable value has be5 consid]ably depreciat$1 & x is n[ unt5ant$4 ,9 ,hakodadi1 :i* is a t[n situat$ v simil>ly to ,gibralt>1 p>tly built on ! slope ( a high rocky m\nta9 & p>tly on a level pla91 f :i* ! m\nta9 rises1 ! rule is simil> to t = ,tokio1 namely1 t ! l[1 flat gr\nd is %ak5 m sev]ely ?an ! high gr\nd4 ,at ,yokohama1 sixte5 miles s\?-we/ f ,tokio1 ! rule is rev]s$1 z 0 v cle>ly demon/rat$ by ! e>?quake ( ,febru>y #ahhj1 :5 almo/ e h\se ^u ! high gr\nd lo/ its *imney1 :il/ on ! l[ gr\nd !re 0 sc>cely any damage done2 ! only places on ! l[ gr\nd :i* suff]$ 7 ^? ne> to ! base ( ! hills4 ,! evid5ce z to ! relative value ( h>d gr\nd z comp>$ ) s(t gr\nd1 = ! f\ndation ( a build+1 is v conflict+4 ,sometimes ! h>d gr\nd has prov$ ! bett] f\ndation & sometimes ! s(t]1 & ! sup]iority ( "o ov] ! o!r dep5ds1 no d\bt1 ^u a v>iety ( local circum/ances4 ,^! latt] obs]vations op5 up ! inquiry z to ! ext5t to :i* ! int5sity ( an e>?quake may be modifi$ by ! topography ( ! di/urb$ area4 ,! sw+ ( m\nta9s4--,if an e>?quake wave is pass+ ?r\gh gr\nd ! surface ( :i* is level1 s long z ?is gr\nd is homog5e\s1 z ! wave travels fur!r & fur!r we %\ld expect its en]gy to become less & less1 until1 f9ally1 x w\ld ins5sibly die out4 ,if1 h[ev]1 we h /&+ ^u ?is pla9 a m\nta91 judg+ f ,mallet's rem>ks1 ?is m\nta9 w\ld be set 9 a /ate ( vibration mu* 9 ! same way z a h\se is set 9 vibration1 & x w\ld t5d to oscillate backw>d & =w>d ) a p]iod ( vibration dep5d5t ^u ! nature ( its mat]ials1 size1 & =m4 ,! upp] portion ( ?is m\nta9 w\ld1 9 consequ5ce1 sw+ ?r\gh a great] arc ?an ! l[] portion1 & build+s situat$ on ! top ( x w\ld sw+ to & fro ?r\gh a great] arc ?an ^? :i* 7 situat$ ne> its foot4 ,?is explanation :y build+s situat$ on ! top ( a m\nta9 %\ld suff] m ?an ^? situat$ on a pla91 is "o :i* 0 (f]$ by ,mallet :5 writ+ ( ! ,neapolitan e>?quake4 ,he tells u t t[ns on hills are #8rock$ z on ! top ( ma/s1' & if we accept ?is explanation x w\ld1 9 fact1 be "o reason :y ! h\ses situat$ on ! ,bluff at ,yokohama suff]$ m ?an ^? situat$ 9 ! settlem5t4 ,?is explanation is giv5 on acc\nt ( ! great au?ority x claims z a consequ5ce ( its s\rce4 ,x is n cle> h[ ! /atem5t c be support$1 z diff]5t portions ( ! m\nta9 receive mom5tum 9 opposite directions at ! same "t4 ,want ( support on ! faces ( hills4--,:5 a wave ( ela/ic compression is propagat$ ?r\gh a m$ium1 we see t ! en]gy ( motion is be+ cont9ually transmitt$ f p>ticle to p>ticle ( t m$ium4 ,a p>ticle1 9 mov+ =w>ds1 meets ) an ela/ic resi/ance ( ! p>ticles t[>ds :i* x moves1 b1 ov]com+ ^! resi/ances1 x causes ^! latt] p>ticles to move1 & 9 turn to transmit ! en]gy to o!rs fur!r on4 ,s long z ! m$ium 9 :i* ?is transf] ( en]gy is cont9u\s1 ea* p>ticle has a limit to its ext5t ( motion1 dep5d5t on ! nature ( ! m$ium4 ,:51 h[ev]1 ! m$ium1 :i* we w suppose to be ! e>?1 is n cont9u\s1 b sudd5ly t]m9ates ) a cliff or sc>p1 ! p>ticles adjac5t to ?is cliff or sc>p1 hav+ no resi/ance (f]$ to _! =w>d motion1 are %ot =w>d1 &1 consequ5tly1 ! gr\nd "h is subject$ to m ext5sive vibrations ?an at ^? places :]e x 0 cont9u\s4 ,?is may be illu/rat$ by a r[ ( m>bles ly+ 9 a horizontal groove2 a s+le m>ble roll$ aga9/ "o end ( ?is r[ w give a concussion :i* w run ?r\gh ! *a91 l ! bump+ ( an eng9e aga9/ a r[ ( railway c>s1 & z a result1 ! m>ble at ! opposite end ( ! r[1 be+ )\t support1 w fly (f4 ,tyndall illu/rates ! same ?+ ) 8 well kn[n r[ ( boys1 ea* "o /&+ ) 8 arms /ret*$ out & 8 h&s re/+ ^u ! %\ld]s ( ! boy be=e him4 ,a pu% be+ giv5 to ! boy at ! back1 ! effect is to transmit a pu% to ! fir/ boy1 :o1 be+ unsupport$1 flies =w>d4 ,9 ! case ( "s e>?quakes1 mo/ disa/r\s results h occurr$ :i* seem only to admit ( an explanation su* z ?is4 ,a rem>kable in/ance ( ?is k9d occurr$ :5 ! great e>?quake ( #aheg #8swept along ! ,alps f ,g5eva to ! ea/-nor?-ea/1 & its cre/ rea*$ ! edge ( ! deep gl5 betwe5 ,z]matt & ,visp4 ,!n ! upp] "p ( ! wave-movem5t1 a ?\s& or two ?\s& feet 9 dep? f ! surface1 came to an end2 ! =w>d pulsation act$ l ! break] ( ! sea1 & heavy falls ( rock encumb]$ ! we/]n side ( ! valley4' ,e>?quake %ad[s4--,if a m\nta9 /&s ^u a pla9 ?r\gh :i* an ela/ic wave is pass+1 :i* is almo/ horizontal1 ! m\nta9 is1 s to speak1 9 ! %ad[ ( su* a wave4 ,if we only consid] ! normal motion ( ?is wave1 we see t ! only motion :i* ! m\nta9 c obta9 w be a wave ( ela/ic di/ortion produc$ by a %e>+ =ce along ! pla9 ( ! base4 ,%\ld1 h[ev]1 ! wave approa* ! m\nta9 f bel[1 & em]ge into x at a c]ta9 angle1 only ! portion ( ! m\nta9 on ! side f :i* ! wave advanc$ c\ld rema9 9 %ad[1 :il/ ! portion on ! opposite side w\ld be ?r[n into a /ate ( compression & ext5sion4 ,portions 9 %ad[1 h[ev]1 w\ld be subject to waves ( ela/ic di/ortion4 ,9 a mann] simil> to ?is we may imag9e t c]ta9 portions ( ! bluff1 s f> z ! advanc+ wave 0 conc]n$1 7 9 %ad[1 & ?us sav$ f ! imm$iate influ5ce ( ! direct %ock4 ,a hypo!tical case ( su* a %ad[ is %[n 9 ! accompany+ section1 illu/rat+ ! cont\r ( ! gr\nd at ,yokohama4 ,! situation :i* might be 9 ! %ad[ ( "o %ock1 h[ev]1 x is q possible might n be 9 t ( ano!r4 ,we mu/ also rememb] t a place 9 %ad[ = a direct %ock might be affect$ by reflect$ waves1 & also by ! transv]se vibrations ( ! direct %ock4 ,^! effects are ov] & above ! effects produc$ by ! waves ( ela/ic di/ortion j ref]r$ to4 ,x might be ask$ :e!r :ole c\ntries1 l ,engl&1 :i* are b seldom %ak51 are 9 %ad[4 ,illu/ration3 ,,fig4 #bg4--;,hypo!tical section at ,yokohama4 ,de/ruction due to ! int]f]5ce ( waves4--,ref]r+ to ! section ( ! gr\nd at ,yokohama 7,fig4 #bg71 x w be se5 t bo? ! settlem5t & ! bluff /& ^u b$s ( gravel capp+ horizontal b$s ( grey tuff4 ,! gravel ( t portion ( ! settlem5t on ! seabo>d orig9ally =m$ ! l9e ( a %+le bea*4 ,t portion ( ! settlem5t back f ! sea /&s ^u gr\nd :i* 0 orig9ally m>%y4 ,9 ! c5tral portions ( ! settlem5t ?is b$ ( gravel is v ?ick1 p]haps #ajj feet or s1 b z y ne> ! edge ( ! bluff x probably becomes ?9n]1 until x f9ally dies out ^u ! flanks ( ! sc>ps4 ,on ! top ( ! bluff1 ! b$s ( gravel w1 9 e probability1 be g5]ally ?9n] ?an !y are ^u ! l[] level4 ,! b$s ( tuff1 :i* is a s(t grey-col\r$ clay-l rock1 produc$ by ! solidification ( volcanic mud1 appe>1 :5 walk+ on ! seabo>d1 to be horizontally /ratifi$4 ,if !re is a dip inl&1 x is 9 all probability v slight4 ,"h & !re ! b$s slightly fault$4 ,tak5 z a :ole we may consid] ^! b$s z be+ tol]ably homog5e\s1 & an e>?quake 9 pass+ ?r\gh !m w\ld meet ) b little reflection or refraction4 ,at ! junction ( ^! b$s ) ! ov]ly+ gravels1 bo? reflection & refraction w\ld comp>atively be v great4 ,on ent]+ ! gravel1 z ! wave w\ld be pass+ into a less ela/ic m$ium1 ! direction ( ! wave w\ld be b5t t[>ds ! p]p5dicul> to ! l9e ( junction1 & ! angle ( em]g5ce at ! surface w\ld consequ5tly be augm5t$4 ,at ! surface c]ta9 reflection w\ld also take place1 b ! *ief reflections w\ld be ^? at ! junction ( ! tuff & ! alluvium4 ,"u ! settlem5t x is probable t all ! reflections :i* took place w\ld be s+le4 ,?us wave fronts l ,a#a advanc+ 9 a direction p>allel to ! l9e a#a2 w\ld be reflect$ 9 a direction a#b & give rise to a s]ies ( reflect$ waves ,a#b4 ,^! are %[n by ?ick] l9es4 ,simil>ly all ! neighb\r+ waves to ! "r & left ( ,a#a w\ld give rise to a s]ies ( reflect$ waves4 ,if ! l9es drawn repres5t+ wave fronts are di/ricts ( compression1 !n1 :]e two ( ! l9es cross ea* o!r1 !re w\ld be d\ble en]gy 9 produc+ compression4 ,simil>ly1 di/ricts ( r>efaction might accord1 &1 aga91 compression ( "o wave might meet ) ! r>efaction ( ano!r & a neutralisation ( effect take place4 ,a diagram illu/rat+ concurr5ce & int]f]5ce ( ?is description is giv5 9 ,le ,conte's #8,elem5ts ( ,geology1' p4 #aae4 ,! int]f]5ce :i* has be5 spok5 (1 h[ev]1 is n ! greate/ :i* w\ld occur4 ,! greate/ w\ld probably be b5ea? ! bluff & ! sc>ps :i* run d[n to jo9 ! level gr\nd bel[4 ,?is w\ld be ! case because x is a probability t !re might n only be cases ( int]f]5ce ( s+le reflect$ waves1 b also ( waves :i* _h be5 n only twice b p]haps ?rice reflect$4 ,= example1 a wave l ,b#a 7:i* is p>allel to ,a#a ( ! fir/ supposition71 advanc+ 9 a direction p>allel to b#a might be reflect$ along ! l9e b#b giv+ rise to waves l ,b#b1 :i* 9 turn might be reflect$ along b#c giv+ rise to waves l ,b#c4 ,! numb] ( di/ricts :]e !re w\ld be concurr5ce & int]f]5ce w\ld1 9 consequ5ce ( ! numb] ( times waves might be reflect$1 be augm5t$4 ,"h ! viol5ce ( ! %ock w\ld1 at c]ta9 po9ts1 be consid]ably increas$1 b z a g5]al result en]gy mu/ be lo/1 s t ev5 if "s ( ! reflect$ waves f\nd _! way into ! portion we h reg>d$ z be+ 9 %ad[1 _! int5sity w\ld n be s great z if !y _h ent]$ x directly4 ,! %ak+ d[n ( loose mat]ials f ! sides ( hills may be p>tially expla9$ on ! assumption ( an increas$ di/urbance due to int]f]5ce4 ,e>?quake bridges4--,9 c]ta9 p>ts ( ,s\? ,am]ica !re appe> to exi/ tracts ( gr\nd :i* are practically exempt f e>?quake %ocks1 :il/ ! :ole c\ntry ar\nd is sometimes viol5tly %ak54 ,x w\ld seem z if ! %ock passes b5ea? su* a di/rict z wat] passes b5ea? a bridge1 & = ?is reason ^! di/ricts h be5 *ri/5$ #8bridges4' ,?is ph5om5on appe>s to dep5d ^u ! nature ( ! und]ly+ soil4 ,:5 an ela/ic wave passes f "o b$ ( rock to ano!r ( a diff]5t "*1 a c]ta9 portion ( ! wave is reflect$1 :ile ! rema9d] ( x is transmitt$ & refract$1 & #8bridges' we may conceive ( z occurr+ :]e ! ph5om5on ( total reflection occurs4 ,9 ! in/ances giv5 ( s(t mat]ials hav+ prov$ good f\ndations1 x 0 assum$ t !y _h *iefly act$ z absorb]s ( mom5tum4 ,!y h also act$ z reflect+ surfaces1 & :]e no effects h be5 felt by ^? resid+ on !m1 ?is may h be5 ! result ( total reflection1 & ! s(t b$s ?us h play$ ! "p ( bridges4 ,fu*s gives an example tak5 f ! records ( ! ,syrian e>?quake ( #ahcg1 :]e n only neighb\r+ villages suff]$ diff]5tly1 b ev5 neighb\r+ h\ses4 ,9 "o case a h\se 0 entirely de/roy$1 :il/ 9 ! next h\se no?+ 0 felt4 ,9 ,japan1 at a place call$ ,*o%i1 ab\t #ee miles ea/ ( ! capital1 e>?quakes are b seldom felt1 al?\gh ! surr\nd+ di/ricts may be sev]ely %ak54 ,f descriptions ( ?is place x w\ld appe> t !re is a l>ge basaltic boss ris+ 9 ! mid/ ( alluvial /rata4 ,! immunity f e>?quakes 9 ?is di/rict has probably giv5 rise to ! my? ( ! ,kanam rock1 :i* is a /one suppos$ to re/ ^u ! head ( a mon/r\s catfi% 7,namadzu71 :i* by its wri?+s causes ! %ak+s s (t5 felt 9 ?is "p ( ! _w4#cd ,pr(4 ,d4 ,s4 ,m>t91 writ+ on ! e>?quake ( ,new ,engl& 9 #ahgd1 says t x 0 felt at f\r po9ts2 x 0 felt 9 ! he>t ( ,brooklyn all )9 a circle ( half a mile across2 #8& ?is fact w\ld sugge/ t a ridge ( rock p]haps approa*es ! surface at t po9t1 ?\gh none is kn[n to appe>4'#ce ,! subject ( special di/ricts1 :i* are m or less protect$ f sev]e %ak+s1 w be aga9 ref]r$ to1 & x w be se5 t aft] a seismic survey has be5 made ev5 ( a c\ntry l ,japan1 :]e !re are on ! av]age at lea/ two e>?quakes p] day1 x is possible to *oose a place to build 9 z free f e>?quakes z ,great ,brita94 ,g5]al examples ( e>?quake effects4--,! foll[+ examples ( e>?quake effects are drawn f ,mallet's acc\nt ( ! ,neapolitan e>?quake ( #aheg4 ,at a t[n call$ ,polla !re 0 great de/ruction4 ,judg+ f ! fissures 9 ! p>ts t rema9$ /&+ x seem$ t ! em]g5ce ( ! %ock _h be5 m v]tical 9 ! upp] "p ( ! t[n ?an 9 ! l[]1 prov+ t :atev] _h be5 ! angle bel[1 ! hill _h itself vibrat$1 :i*1 be+ horizontal1 _h modifi$ ! angle ( ! fissures4 ,diano suff]$ b little1 p>tly because x 0 well built1 & p>tly on acc\nt ( its situation1 :i* 0 su* t be=e ! %ock rea*$ x ! di/urbance _h to pass f b$s ( clay into ne>ly v]tically plac$ b$s ( lime/one4 ,also a great portion ( ! %ock 0 cut (f by ! ,vallone del ,raccio to ! nor? & nor?-we/ ( ! t[n4 ,"h ! effects ( ! p>tial ext9ction ( ! wave on ! #8free outlay+ /ratum' 7 visible 9 ! masses ( project$ rock4 ,ca/ellucio did n suff] because its well buttress$ knoll 0 end on to ! direction ( %ock1 & on acc\nt ( a b>ri] ( v]tical breccia b$s protect+ x ^u ! ea/4 ,p]tosa /&s on a m\nd4 ,! de/ruction 0 lea/ 9 ! s\!rn "p ( ! t[n4 ,f ! relation ( ! b$s ( breccia on :i* ! t[n /&s1 & ! direction ( ! wave pa?1 x is evid5t t ! s\!rn "p ( ! t[n receiv$ ! =ce ( ! %ock ?r\gh a great] ?ickness ( ! breccia b$s ?an ! o!r p>ts did4 ,pet9a1 /&+ on a level lime/one spur jutt+ out f a m\nta9 slope1 suff]$ no?+1 :il/ ,anletta five miles to ! s\?-we/1 & ,p]tosa six miles di/ant1 7 9 great "p pro/rat$4 7#a7 ,! t]race did n vibrate1 & 7#b7 betwe5 ,pet9a & ,anletta !re is almo/ #f1jjj feet ( pil$ up lime/one1 s t any %ock em]g5t at a /eep angle _h to pass up transv]sely ?r\gh ^! b$s4 ,protection ( build+s4--,9 addition to giv+ prop] con/ruction to our build+s1 *oos+ prop] f\ndations & positions = !m1 some?+ might possibly be done to w>d (f ! de/ructive effects ( an e>?quake4 ,we read t ! ,temple ( ,diana at ,ephesus 0 built on ! edge ( a m>%1 9 ord] to w>d (f ! effect ( e>?quakes4 ,pl9y tells u t ! ,capitol ( ,rome 0 sav$ by ! ,catacombs1 & ,elise ,reclus#cf says t ! ,romans & ,hell5es f\nd out t cav]ns1 wells1 & qu>ries ret>d$ ! di/urbance ( ! e>?1 & protect$ edifices 9 _! neighb\rhood4 ,! t[] ( ,capua 0 sav$ by its num]\s wells4 ,viv5zis ass]ts t 9 build+ ! ,capitol ! ,romans sunk wells to weak5 ! effects ( t]re/rial oscillations4 ,humboldt relates ! same ( ! inhabitants ( ,san ,dom+o4 ,quito is said to receive protection f ! num]\s caons 9 ! neighb\rhood1 :il/ ,lactacunga1 fifte5 miles di/ant1 has (t5 be5 de/roy$4 ,simil>ly1 x is extremely probable t _m portions ( ,tokio h f "t to "t be5 protect$ m or less f ! sev]e %ocks ( e>?quakes by ! num]\s moats & deep canals :i* int]sect x4 ,al?\gh we are n prep>$ to say h[ f> artificial op5+s ( ?is description are effectual 9 w>d+ (f ! %ocks ( e>?quakes1 f !oretical consid]ations1 & f ! fact t _! use has be5 discov]$ by p]sons :o1 9 all probability1 7 )\t ! means ( mak+ !oretical d$uctions1 ! sugge/ions :i* !y (f] are wor?y ( att5tion4 ,g5]al conclusions4--,! foll[+ are a few ( ! m important results :i* may be drawn f ! prec$+ *apt]3-- #a4 ,9 *oos+ a site = a h\se f9d out by ! exp]i5ce ( o!rs or exp]im5tal inve/igation ! localities :i* are lea/ di/urb$4 ,9 "s cases ?is w be ^u ! hills1 9 o!rs 9 ! valleys & on ! pla9s4 #b4 ,a wide op5 pla9 is less likely to be di/urb$ ?an a position on a hill4 #c4 ,avoid loose mat]ials re/+ on h>d] /rata4 #d4 ,if ! %ak+s are def9ite 9 direction1 place ! blank walls p>allel to su* directions1 & ! walls ) _m op5+s 9 !m at "r angles to su* directions4 #e4 ,avoid ! edges ( sc>ps or bluffs1 bo? above & bel[4 #f4 ,s arrange ! op5+s 9 a wall1 t = horizontal /resses ! wall %all be ( equal /r5g? = all sections at "r angles4 #g4 ,place l9tels ov] flat ar*es ( brick or /one4 #h4 ,to )/& de/ructive %ocks ei!r rigidly foll[ "o or o!r ( ! two sy/ems ( con/ruct+ an e>?quake-pro( build+4 ,! light build+ on loose f\ndations is ! *eap] & probably ! bett]4 #i4 ,let all portions ( a build+ h _! natural p]iods ( vibration ne>ly equal4 #aj4 ,if x is a necessity t "o portion ( a build+ %\ld h a v diff]5t p]iod ( vibration to ! rema9d]1 z = in/ance a brick *imney 9 a wood5 h\se1 x w\ld seem advisable ei!r to let ^! two portions be suffici5tly free to h an indep5d5t motion1 or else !y mu/ be b\nd toge!r ) great /r5g?4 #aa4 ,avoid heavy topp$ ro(s & *imneys4 ,if ! f\ndations 7 free ! ro( might be heavy4 #ab4 ,9 brick or /one "w use good cem5t4 #ac4 ,let ar*ways curve into _! abutm5ts4 #ad4 ,let ro(s h a l[ pit*1 & ! tiles1 especially ^? ^u ! ridges1 be well secur$4 ,,*apt] ,,viii4 ,,effects ,,( ,,e>?quakes ,,on ,,l&1 #a4 ,cracks & fissures--,mat]ials dis*>g$ f fissures--,explanation ( fissure ph5om5a4 #b4 ,di/urbances 9 lakes1 riv]s1 spr+s1 wells1 fum>oles1 c4--,explanation ( ^! latt] ph5om5a4 #c4 ,p]man5t displacem5t ( gr\nd--,on coa/ l9es--,level tracts--,among m\nta9s--,explanation ( ^! movem5ts4 ,cracks & fissures =m$ 9 ! gr\nd4--,almo/ all l>ge e>?quakes h produc$ cracks 9 ! gr\nd4 ,! cracks :i* 7 f\nd 9 ! gr\nd at ,yokohama 7,febru>y #bb1 #ahhj7 7 ab\t two or ?ree in*es wide1 & f tw5ty to =ty y>ds 9 l5g?4 ,!y c\ld be be/ se5 z l9es along a road runn+ ne> ! upp] edge ( "s cliffs :i* ov]look ! sea at t place4 ,! reason t cracks %\ld h occurr$ 9 su* a position r ?an 9 o!rs 0 probably ow+ to ! great] motion at su* a place1 due to ! face ( ! cliff be+ unsupport$1 & !re be+ no resi/ance oppos$ to its =w>d motion4 ,x (t5 happ5s t e>?quake cracks are _m feet 9 wid?4 ,at ! ,calabrian e>?quake ( #aghc1 "o or two ( ! crevasses :i* 7 =m$ 7 m ?an #ajj feet 9 wid? & #bjj feet 9 dep?4 ,_! l5g?s v>i$ f half a mile to a mile4#cg ,besides ^! l>ge cracks1 _m small] ones ( "o or two feet 9 bread? & ( great l5g? 7 =m$4 ,9 ! l>ge fissures _m h\ses 7 engulf$4 ,subsequ5t excavations %[$ t by ! clos+ ( ! fissures ^! _h be5 jamm$ toge!r to =m "o compact mass4 ,^! cracks are usually m or less p>allel1 & at ! same "t p>allel to "s topographical feature1 l a range ( m\nta9s4 ,= example1 ! cracks :i* 7 =m$ by ! ,mississippi e>?quake ( #ahab ran f nor?-ea/ to s\?-we/ p>allel to ! ,alleghanies4 ,by succe$+ %ocks ^! crevasses are sometimes clos$ & sometimes op5$ /ill wid]4 ,_! p]man5cy w also dep5d ^u ! nature ( ! mat]ials 9 :i* !y are made4 ,dur+ an e>?quake l>ge cracks may sudd5ly op5 & %ut4 ,dur+ ! convulsions ( #afib :i* de/roy$ ,port ,royal1 x is said t _m ( ! fissures :i* 7 =m$1 op5$ & %ut4 ,9 "s ( ^!1 p 7 entirely swall[$ up & buri$4 ,9 o!rs !y 7 trapp$ by ! middle1 & ev5 by ! neck1 :]e if n kill$ in/antane\sly !y p]i%$ sl[ly4 ,subsequ5tly _! project+ p>ts =m$ food = dogs4#ch ,! e>?quake :i*1 ,july #ah1 #ahhj1 %ook ! ,philipp9es caus$ _m fissures to be f\nd1 :i* 9 "s places 7 s num]\s t ! gr\nd 0 brok5 up into /eps4 ,ne> to ! village ( ,san ,antonio ! soil 0 s di/urb$ t ! surface ( a field ( sug>-canes 0 s alt]$ t 9 "s cases ! top ( "o r[ ( full gr[n plants 0 on a level ) ! roots ( ! next4 ,into "o su* fissure a boat disappe>$1 & into ano!r1 a *ild4 ,subsequ5tly ! *ild 0 excavat$1 & its body1 :i* 0 f\nd a %ort di/ance bel[ ! surface1 0 completely cru%$4#ci ,at ! "t ( ! ,riobamba e>?quake1 n only 7 m5 engulf$1 b animals1 l mules1 also sank into ! fissures :i* 7 =m$4 ,! fissures :i* 7 =m$ at ! "t ( ! ,ow5's ,valley e>?quake 9 #ahgb ext5d$ = miles ne>ly p>allel to ! neighb\r+ ,si]ras4 ,9 "s places ! gr\nd betwe5 ! fissures sank tw5ty or ?irty feet1 & at "o place ab\t ?ree miles ea/ ( ,indep5d5ce1 a portion ( ! road 0 c>ri$ eighte5 feet to ! s\? by a fissure4#dj ,speak+ g5]ally1 x may be said t all l>ge e>?quakes are accompani$ by ! =mation ( fissures4 ,! ,japanese h a say+ t at ! "t ( a l>ge e>?quake p]sons mu/ run to a bamboo grove4 ,! object ( ?is is to escape ! dang] ( be+ engulf$ 9 fissures1 ! gr\nd b5ea? a bamboo grove be+ s nett$ toge!r ) f9e roots t x is almo/ impossible = x to be r5t op54 ,mat]ials dis*>g$ f fissures4--,toge!r ) ! op5+ ( cracks 9 ! e>? x (t5 has happ5$ t wat]1 mud1 vap\rs1 gases1 & o!r mat]ials1 h be5 eject$4 ,at ! "t ( ! ,mississippi e>?quake wat]1 mix$ ) s& & mud1 0 ?r[n out ) su* viol5ce t x spurt$ above ! tops ( ! highe/ trees4 ,9 ,italy su* ph5om5a h (t5 be5 repeat$4 ,f ! fissures :i* 7 =m$ 9 #afib at ! "t ( ! e>?quakes 9 ,sicily1 wat] issu$ :i* 9 "s in/ances 0 salt4#da ,by ! ,ca*> e>?quake 7,janu>y #aj1 #ahfi7 num]\s fissures 7 =m$ p>allel to ! banks ( a riv]1 f ?is wat] & mud 7 eject$4 ,dr4 ,oldham1 :o describes ?is e>?quake1 says t ! fir/ %ot ( dry mud or s& 0 mi/ak5 = smoke or /eam4 ,! wat] 0 f\l1 & hott] ?an surface wat] at ! "t1 b only slightly s2 & ! sulphur\s smell 0 no?+ m ?an y w\ld p]ceive 9 /irr+ up ! mud at ! bottom ( any /agnant pool :i* _h la9 undi/urb$ = "s "t4#db ,9 #agee1 :5 ,tauris 0 de/roy$1 boil+ wat] issu$ f ! cracks :i* 7 =m$4 ,simil> ph5om5a 7 witness$ at a place eight miles f ,la ,banca 9 ,mexico1 9 ! ye> #ahbj4 ,"p ( ?is hot wat] 0 pure & "p 0 muddy4 ,sometimes ! wat] :i* has be5 eject$ has be5 s muddy t ! mud has be5 collect$ to =m small hills4 ,?is 0 ! case at ! "t ( ! ,riobamba e>?quake4 ,! mud 9 ?is case consi/$ p>tly ( coal1 fragm5ts ( augite1 & %ells ( infusoria4 ,at ! "t ( ! ,jamaica e>?quake m5 :o _h fall5 into crevices 7 9 "s cases ?r[n out aga9 by issu+ wat]4 ,sometimes1 z has already be5 m5tion$1 vap\r1 gases1 & ev5 flames issue f fissures4 ,vap\r ( sulphur appe>s to be exce$+ly common4 ,kluge says t _m fi% 7 kill$ 9 consequ5ce ( ! sulphur\s vap\rs :i* rose 9 ! sea ne> to ! coa/ ( ,new ,zeal& 9 #ahee4 ,on ,decemb] #ad1 #agig1 an insupportable smell ( sulphur 0 obs]v$ to h accompani$ ! e>?quake :i* at t "t %ook ,cumana1 :i* 0 greate/ :5 ! di/urbance 0 greate/4 ,sulphur\s fumes :i* 7 combu/ible 7 bel*$ out ( ! e>? at ! "t ( ! ,jamaica e>?quake 9 #afib4 ,! smell :i* accompani$ ?is 0 s p[]ful t x caus$ a g5]al sickness :i* swept away ab\t #c1jjj p]sons4#dc ,f ! fissures =m$ at ,concepcion 9 #ahce1 wat]1 :i* 0 black & ftid1 issu$4#dd ,! e>?quakes ( ,new ,engl& 9 #agbg 7 accompani$ by ! =mation ( fissures1 f :i* s& & wat] boil$ out 9 suffici5t quantity to =m a quagmire4 ,9 "s places a% & sulphur are said to h be5 eject$4 ,at "o h\se ! /9k ( sulphur accompany+ ! e>?quake 0 s great t ! family c\ld n be> to rema9 9 doors4#de ,emanations ( gas sometimes appe> to h bur/ out f subm>9e s\rces4 ,?us ! e>?quake at ,lima1 9 ,m>*1 #ahfe1 0 accompani$ ) great agitation ( ! wat] & an od\r ( sulphurett$ & c>burett$ hydrog54 ,?is =m] gas 0 develop$ to su* an ext5t t ! :ite pa9t ( ! ,u4,s4 %ip #8,lanca/]' 0 black5$4#df ,) ! smell1 flames h sometimes be5 obs]v$1 z1 = in/ance1 at ! "t ( ! ,lisbon e>?quake4 ,at ! "t ( ! e>?quakes ( #ahaa & #ahac1 9 ! ,mississippi valley1 /eam & smoke issu$ f "s ( ! fissures :i* 7 =m$4 ,in/ances are record$ :]e /ones h be5 %ot up f fissures unaccompani$ by wat]1 z1 = in/ance1 at ! e>?quake ( ,pa/o 7,janu>y1 #ahcd74 ,x is imag9$ t ! propell+ p[] mu/ h be5 ! sudd5 expansion ( escap+ gases4 ,x has be5 sugge/$ t flames se5 above fissures might p]haps be due to ! burn+ ( mat]ials l sulphur4 ,mr4 ,d4 ,=bes1 :o exam9$ ! effects ( ! e>?quakes ( ,m5doza1 :i* 7 felt = a di/ance ( #a1bjj miles1 says t :]e ! h>d rock came to ! surface !re 7 no traces ( fissures1 ^! be+ entirely conf9$ to ! alluvium4 ,! rum\rs ( fire & smoke hav+ appe>$ at "s ( ! fissures 7 )\t f\ndation1 ! presum$ smoke be+ no?+ b du/4#dg ,9 addition to flames lights appe> (t5 to h be5 obs]v$1 ! orig9 ( :i* _c be easily expla9$4 ,! e>?quake ( ,novemb] #bb1 #agea1 at ,g5oa is said to h be5 accompani$ by a light l t ( a prodigi\s fire :i* seem$ to arise out ( ! gr\nd4#dh ,explanation ( fissure ph5om5a4--,! mann] 9 :i* fissures are =m$ has already be5 expla9$ :5 ref]r+ to ! want ( support 9 ! face ( hills 7page #acf74 ,simil> rem>ks may be appli$ to ! banks ( riv]s & all depressions1 :e!r natural or artificial1 :i* h a /eep slope4 ,at su* places ! wave ( %ock em]ges on a free surface1 :i*1 be+ unsupport$ 9 ! direction ( its motion1 t5ds to te> itself away f ! mat]ial beh9d1 & =m a fissure p>allel to ! face ( ! free surface4 ,! di/ance ( ! fissure f ! face ( ! free surface w1 !oretically1 be equal to half ! amplitude ( ! wave ( motion1 "o half t5d+ to move =w>ds1 & ! o!r half backw>ds4 ,! reason t wat] & o!r mat]ials ru% =? f fissures has be5 expla9$ by ,s*l] z be+ due to cracks hav+ be5 op5$ ?r\gh imp]vi\s /rata1 :i*1 be=e ! e>?quake1 by _! cont9uity prev5t$ ! ris+ ( subt]ranean wat] "u hydro/atic pressure4#di ,kluge expla9s ! com+ up ( ! wat]s z be+ due to ! same causes :i* he consid]s may be ! orig9 ( di/urbances 9 ! sea4 ,! mo/ reasonable explanations ( ! eruption ( wat]1 mud1 s&1 & gas ?r\gh fissures are ^? giv5 by ,oldham & ,mallet 9 _! acc\nt ( ! ,ca*> e>?quake4 ,9 ! case ( a horizontal %ock pass+ ?r\gh a b$ ( ooze or wat]-be>+ /rata1 ! ela/ic wave w t5d to pack up ! wat] dur+ ! =w>d motion to su* an ext5t t x w fl[ or sp\t up ?r\gh any ap]ture communicat+ ) ! surface4 ,by ! repetition ( ^! movem5ts caus+ ejections1 s& or mud cones1 l ^? produc$ by a volcanic eruption1 may be =m$1 & by a simil> action wat] may be %ot viol5tly up out ( wells1 z 0 ! case 9 ,jamaica 9 #afib4 ,if an em]g5t wave acts ?r\gh a wat]-be>+ b$ ^u a sup]9cumb5t lay] ( imp]vi\s mat]ial1 ?is upp] lay] is1 dur+ ! upw>d motion1 by its in]tia sudd5ly press$ d[n ^u ! latt]4 ,?is pressure is equal to t :i* w\ld raise ! upp] lay] to a height equal to ! amplitude ( ! motion ( an e>? p>ticle1 & ) a velocity at lea/ equal to ! mean velocity ( ! e>? p>ticle resolv$ 9 ! v]tical direction4 ,= a mom5t ! wat]-be>+ /rata receive an enorm\s squeeze1 & ! wat] or mud />ts up ?r\gh any crevice :i* may be =m$ lead+ to ! surface4 ,f ?is we see t liquids may rise f> beyond ! level due to hydro/atic pressure4#ej ,volg] has attribut$ ! orig9 ( lights or flames appe>+ above fissures to ! friction :i* mu/ take place betwe5 v>i\s rocky mat]ials at ! "t :5 ! fissures are op5$4 ,z confirmatory ( ?is he ref]s to in/ances :]e simil> ph5om5a h be5 obs]v$ at ! "t ( l&slips4 ,at ! "t ( ^! l&slips ! heat develop$ by friction has be5 suffici5tly int5se to conv]t wat] into /eam1 ! t5sion ( :i* ?rew mud & e>? into ! air l ! explosion ( a m9e4#ea ,! gas eruptions :i* occasionally take place ) e>?quakes are probably due to ! op5+ ( fissures communicat+ ) res]voirs or /rata *>g$ ) products ( natural di/illation1 or *emical action1 :i* previ\sly _h accumulat$ b5ea? imp]vi\s /rata4 ,( ! exi/5ce ( su* gases we h abundant evid5ce4 ,9 coal m9es we h fire damp :i* escapes 9 increas$ quantities ) a l[]+ ( ! b>ometrical pressure4 ,9 volcanic regions we h _m examples ( natural spr+s ( c>bon dioxide4 ,^! v>i\s gases sometimes escape 9 quantity1 or erupt )\t ! occurr5ce ( e>?quakes4 ,rossi m5tions an in/ance :]e a few ye>s ago quantities ( fi% 7 kill$ by ! eruption ( gas 9 ! ,tib]1 ne> ,rome4 ,ano!r in/ance is "o :i* occurr$ at ,follonica on ,april #f1 #ahgd4 ,on ! morn+ ( t day _m ( ! /reets & roads 7 cov]$ ) ! dead bodies ( rats & mice4 ,x seem$ z if x _h ra9$ rats4 ,f ! facts t ! bodies ( ! creatures seem$ heal?y1 t ! de/ruction _h happ5$ sudd5ly1 & n come on gradually l an epidemic1 x 0 suppos$ t !y _h be5 de/roy$ by an emanation ( c>bon dioxide4 ,! fact t _m ( !m lay 9 long l9es sugge/$ ! idea t !y _h be5 endeav\r+ to escape at ! "t ( ! eruption4#eb ,if we c suppose sudd5 developm5ts ( gas l ?is to h occasionally accompani$ e>?quakes1 we may sometimes h ! means ( acc\nt+ = ! sickness :i* has be5 felt4 ,di/urbances 9 lakes4--,x has (t5 be5 obs]v$ t1 at ! "t ( l>ge e>?quakes1 lakes h be5 ?r[n into viol5t agitation1 & _! wat]s h be5 rais$ or l[]$4 ,at ! "t ( ! great ,lisbon e>?quake1 n only 7 ! wat]s ( ,european lakes ?r[n into a /ate ( oscillation1 b simil> effects 7 produc$ 9 ! great lakes ( ,nor? ,am]ica4 ,9 "s in/ances1 z 9 ! case ( small ponds1 ^! movem5ts may be produc$ by ! horizontal backw>d & =w>d motion ( ! gr\nd4 ,at o!r times !y are probably due to an actual tipp+ ( a portion ( _! bas9s4 ,movem5ts l ^! latt] w be aga9 ref]r$ to 9 ! *apt] on ,e>? ,pulsations4 ,on ,janu>y #bg1 #ahef1 !re 0 a %ock ( e>?quake at ,bailybor\gh1 ,irel&1 :i* occasion$ an adjac5t l\gh to ov]fl[ its banks & ru% into ! t[n ) great impetuosity4 ,9 return+ x swept away two m51 leav+ beh9d a great quantity ( pike & eels ( a prodigi\s gr[?4#ec ,di/urbances 9 riv]s4--,j z lakes h be5 di/urb$1 s also h !re be5 sudd5 di/urbances 9 riv]s4 ,sometimes ^! h ov]fl[$ _! banks1 :il/ at o!r times !y h be5 sudd5ly dri$ up4 ,9 c]ta9 cases ! reason t a portion ( a riv] %\ld h become dry has be5 v app>5t1 z1 = in/ance1 at ! "t ( ! ,z5koji e>?quake 9 ,japan 9 #ahdg1 :5 ! ,%ikuma-gawa became p>tly dry 9 consequ5ce ( ! l>ge masses ( e>? :i* _h be5 %ak5 d[n f ov]hang+ cliffs damm+ a portion ( its c\rse1 & ?us =m+1 fir/1 lakes1 & subsequ5tly1 new wat]-c\rses4 ,z ano!r example1 out ( ! _m :i* might be quot$1 may be m5tion$ ! sudd5 dry+ up ( ! riv] ,aboat1 a tribut>y ( ! ,magat1 9 ! ,philipp9e ,isl&s1 on ,july #bg1 #ahha1 %ortly aft] a sev]e %ock ( e>?quake4 ,! wat] ( ?is riv] ceas$ to fl[ = two h\rs1 aft] :i* x reappe>$ ) consid]able increase ( volume & ( a r$di% col\r4 ,signor ,e4 ,a4 ,cas>iego1 :o describes ?is1 rem>ks t ! ph5om5on c\ld easily be expla9$ ?r\gh ! slipp+ d[n ( ! /eep banks 9 n>r[ p>ts ( its upp] valley1 by :i* means its fl[ _h be5 ob/ruct$ until ! wat] _h "t to accumulate & pass ov] or demoli% ! ob/ruction4 ,aft] ! e>?quake ( ,belluno 7,june #bi1 #ahgc71 ! torr5t ,tesa1 :i* is ord9>ily limpid1 became v muddy4#ed ,simil> ph5om5a h be5 obs]v$ ev5 9 ,brita91 z1 = in/ance1 9 #aghg1 :51 at ! "t ( a %ock :i* 0 felt 9 ,glasg[1 !re 0 a tempor>y /oppage 9 ! wat]s ( ! ,clyde4 ,aga91 9 #aaaj1 !re 0 a dreadful e>?quake at ,%rewsbury & ,nott+ham1 & ! ,tr5t became s l[ at ,nott+ham t p walk$ ov] x4 ,! e>?quake ( #aaeh1 :i* 0 felt 9 _m p>ts ( ,engl&1 0 accompani$ by ! dry+ up ( ! ,?ames1 :i* 0 s l[ t x c\ld be cross$ on foot ev5 at ,london4#ee ,facts analog\s to ^! are m5tion$ 9 ! acc\nts ( _m l>ge e>?quakes4 ,sometimes riv]s only come muddy or *ange _! col\r4 ,9 an acc\nt ( ! ,lisbon e>?quake we read t "s ( ! riv]s ne> ,neuf*tel sudd5ly became muddy4#ef ,at o!r times l>ge waves are =m$4 ,?us ! e>?quake ( ,kansas 7,april #bd1 #ahfg7 app>5tly creat$ a di/urbance 9 ! riv]s at ,manhattan1 :i* roll$ 9 a heavy wave f ! nor? to ! s\? bank4#eg ,sometimes curi\s ph5om5a h happ5$ ) reg>d to riv]s )\t ! occurr5ce ( e>?quakes4 ,?us1 = in/ance1 on ,novemb] #bg1 #ahch1 !re 0 a simultane\s /oppage ( ! ,teviot1 ,clyde1 & ,ni?4 ,9 ^! riv]s simil> ph5om5a h be5 obs]v$ 9 previ\s ye>s4 ,aga91 on ,janu>y #a1 #agee1 !re 0 a sudd5 s9k+ ( ! riv] ,frooyd1 ne> ,pontypool4 ,?is appe>s to h be5 due to ! wat] s9k+ into *asms :i* 7 sudd5ly op5$4#eh ,effects produc$ 9 spr+s1 wells1 fum>oles1 c4--,spr+s also are (t5 affect$ by e>?quakes4 ,sometimes ! "* ( _! wat]s *ange2 ^? :i* 7 pure become muddy1 :il/ ^? :i* 7 hot h _! temp]ature alt]$4 ,sometimes spr+s h be5 dri$ up1 :il/ at o!r times new spr+s h be5 =m$4 ,?is latt] 0 ! case 9 ,new ,engl& 7,octob] #bg1 #agbg74 ,9 "s places spr+s 7 =m$1 :il/ at o!r places !y 7 ei!r entirely or p>tly dri$ up4#ei ,at & ne> ,lisbon1 9 #agee1 "s f\nta9s became muddy1 o!rs decreas$1 o!rs increas$1 & o!rs dri$ up4 ,at ,montreux1 ,aigle1 & o!r places1 spr+s became turbid4 ,! ba?s at ,toplitz1 9 ,bohemia1 :i* 7 discov]$ 9 ,a4,d4 #gfb1 7 s]i\sly affect$ by ! same e>?quake4 ,previ\s to ! e>?quake x is said t !y _h always giv5 a con/ant supply ( hot wat]4 ,at ?is "t1 h[ev]1 ! *ief spr+ s5t up va/ quantities ( wat] & ran ov]4 ,"o h\r be=e ?is x _h gr[n turbid & fl[$ muddy4 ,aft] ?is x /opp$ = ab\t "o m9ute1 b recomm5c$ to fl[ ) prodigi\s viol5ce1 driv+ be=e x consid]able quantities ( r$di% o*re4 ,f9ally1 x settl$ back to its orig9al cle> /ate & fl[$ z be=e4#fj ,9 #ahee1 at ! e>?quake ( ,wallis1 _m new spr+s bur/ =?1 & "s ( ^! 9 ,nicolai ,?ale 7 s ri* 9 iron t !y quickly =m$ a deposit ( o*re4 ,at ! "t ( ! ,belluno e>?quake 7,june #bi1 #ahgc71 a hot spr+1 ,la ,v5a d',oro1 sudd5ly became r$4#fa ,! foll[+ examples ( l *anges are tak5 f ! writ+s ( ,fu*s4#fb ,9 #agch ! hot spr+s ( ,/4 ,euphema rose consid]ably 9 _! temp]ature4 ,dur+ ! e>?quake ( ,octob]1 #ahdh1 ! hot spr+s ( ,ardebil1 :i* usually _h a temp]ature ( f #dd to #df ,c41 rose s high t _! temp]ature 0 suffici5t to cause scald+4 ,at ! "t ( ! e>?quake ( ,wallis1 9 #ahee1 ! temp]ature ( hot spr+s rose #g1 & ! quantity ( wat] increas$ ?ree times4 ,dur+ ! e>?quake ( #ahce 9 ,*ili1 ! spr+s ( ,cauqu5es fell f #aah to #ib ,f4 ,subsequ5tly1 h[ev]1 !y aga9 rose4 ,fum>oles are simil>ly di/urb$4 ,?us1 at ! "t ( ! e>?quakes ( ,m>t9ique 7,septemb]1 #ahge71 ! fum>oles !re %[$ an abnormal activity4#fc ,wells (t5 appe> to be act$ ^u 9 ! same mann] z spr+s4 ,at ! "t ( ! ,cali=nia e>?quake 7,april1 #ahee71 ! level ( ! wat] 9 c]ta9 wells 0 rais$ t5 to twelve feet4 ,a consequ5ce ( ! e>?quake at ,neuf*tel1 9 #agdi1 0 to fill "s ( ! wells ) mud4#fd ,at ,con/ant9ople1 on ,septemb] #b1 #aged1 wells became dry4#fe ,explanation ( ! above ph5om5a4--,t ! wat] 9 spr+s & wells %\ld be caus$ to rise at ! "t ( an e>?quake1 admits ( explanation on ! supposition ( compressions tak+ place simil> to ^? :i* cause ! rise ( wat] 9 fissures4 ,t ! wat] 9 wells & spr+s %\ld be r5d]$ turbid1 is p>tly expla9$ on ! supposition ( m or less dislocation tak+ place 9 ! e>?y or rocky cavities 9 :i* !y are conta9$ or ?r\gh :i* !y fl[4 ,at ! "t ( a l>ge e>?quake x is extremely probable t !re is a g5]al di/urbance 9 ! l9es ( circulation ( subt]ranean wat]s & gases ?r\gh\t ! %ak5 area4 ,by ^! di/urbances1 new wat]s may be br\ght to ! surface1 two or m l9es ( circulation may be unit$1 & ! fl[ ( a spr+ or supply ( a well be augm5t$4 ,fissures1 ?r\gh :i* wat]s rea*$ ! surface1 may be clos$1 wells may become dry1 or spr+s may cease to fl[1 hot spr+s may h _! temp]ature l[]$ by ! additions ( cold wat] f ano!r s\rce1 &1 9 a simil> mann]1 wat]s may be alt]$ 9 _! m9]alisation4 ,an important po9t to be rememb]$ 9 ?is consid]ation is ! mutual dep5d5ce ( v>i\s und]gr\nd wat] supplies1 & ! area ov] :i* any giv5 supply may circulate4 ,a well 9 ! high] "p ( ,l9coln ,hea? is said to be gov]n$ by ! riv] ,tr5t1 :i* is t5 miles di/ant2 :5 ! riv] rises ! well rises 9 proportion1 & :5 ! riv] falls ! wat] 9 ! well falls4#ff ,! *ange :i* is usually obs]v$ 9 hot spr+s is1 t be=e or ) e>?quakes !y increase 9 temp]ature1 b aft]w>ds s9k back to _! normal /ate4 ,?is increase 9 temp]ature may possibly be due to communication be+ op5$ ) new or deep] c5tres ( volcanic activity1 or a tempor>ily increas$ rate ( fl[4 ,t ! wat] issu+ f newly =m$ fissures or spr+s %\ld be hot1 might be expla9$ on ! supposition ( its aris+ f a consid]able dep?1 or f "s volcanic c5tre4 ,x might also be attribut$ to ! heat develop$ by friction at ! op5+ ( ! fissures4 ,^! *anges :i* e>?quakes produce ^u ! und]gr\nd circulation ( wat]s are ph5om5a des]v+ especial att5tion4 ,al?\gh we "k mu* ab\t ! circulation ( surface wat]1 x is b little t we yet "k ab\t ! movem5t ( ! /reams hidd5 f view1 f :i* ^! surface wat]s h _! s\rces4 ,e>?quakes may be reg>d$ z gigantic exp]im5ts on ! circulatory sy/em ( ! e>?1 :i*1 if prop]ly int]pret$1 may yield in=mation ( sci5tific & utilit>ian value4 ,! sudd5 elevations1 depressions1 or lat]al %ift+ ( l>ge tracts ( c\ntry at ! "t ( de/ructive e>?quakes are ph5om5a ) :i* all /ud5ts ( geology are famili>4 ,9 mo/ cases ^! displacem5ts h be5 p]man5t2 & evid5ces ( _m ( ! movem5ts :i* occurr$ )9 ! memory ( man1 rema9 z witnesses ( ! t]rible convulsions ) :i* !y 7 accompani$4 ,movem5ts on coa/ l9es & level tracts4--,at ! "t ( ! great e>?quake ( ,concepcion1 on ,febru>y #bj1 #ahce1 mu* ( ! neighb\r+ coa/ l9e 0 sudd5ly elevat$ f\r or five feet above sea level4 ,?is1 h[ev]1 subsequ5tly sank until x 0 only two feet4 ,a rocky flat1 (f ! isl& ( ,santa ,m>ia1 0 lift$ above high-wat] m>k1 & left cov]$ ) #8gap+ & putrefy+ mussel-%ells1 /ill atta*$ to ! b$ on :i* !y _h liv$4' ,! nor!rn end ( ! isl& itself 0 rais$ t5 feet & ! s\!rn extremity eight feet4#fg ,by ! e>?quake ( #ahci1 ! isl& ( ,lemus1 9 ! ,*onos ,ar*ipelago1 0 sudd5ly elevat$ eight feet4#fh ,( movem5ts l ^!1 especially along ! we/]n %ores ( ,s\? ,am]ica1 ,d>w91 :o paid s mu* att5tion to ?is subject1 has giv5 _m examples4 ,9 #ahbb1 ! %ore ne> ,valp>aiso 0 sudd5ly lift$ up1 & ,d>w9 tells u t he he>d x confid5tly ass]t$ #8t a s5t9el on duty1 imm$iately aft] ! %ock1 saw a "p ( a =t :i* previ\sly 0 n )9 ! l9e ( 8 vision1 & ?is w\ld indicate t ! uplift+ 0 n v]tical4'#fi ,t ! l>ge areas ( l& %\ld be %ift$ p]man5tly 9 horizontal directions1 z well z v]tically1 we %\ld anticipate f ! obs]vations :i* we are able to make ^u l>ge fissures :i* are caus$ by e>?quakes4 ,ano!r rem>kable example ( sudd5 movem5t 9 ! rocky cru/ is t :i* took place dur+ ! e>?quakes ( #ahaa-ab 9 ! valley ( ! ,mississippi1 ne> to ! m\? ( ! ,ohio1 :i* 0 convuls$ to su* a degree1 t lakes1 tw5ty miles 9 ext5t1 7 =m$ 9 ! c\rse ( an h\r4 ,?is c\ntry1 :i* is call$ ! #8sunk c\ntry1' ext5ds "s sev5ty to eighty miles nor? & s\?1 & ?irty miles ea/ & we/4#gj ,9 ! #8,g5tleman's ,magaz9e' we read ( ! little t]ritory ( ,causa ,nova1 9 ,calabria1 be+ sunk tw5ty-n9e feet into ! e>? by an e>?quake1 )\t ?r[+ d[n a h\se4 ,! inhabitants1 be+ w>n$ by a noise1 escap$ into ! fields1 & only five 7 kill$4#ga ,o!r examples ( ^! p]man5t dislocations ( /rata are to be f\nd 9 almo/ e text-book on geology4 ,geological *anges produc$4--,pass+ ov] ! acc\nts ( e>? movem5ts :i* are m or less fictiti\s1 & conf9+ our att5tion to ! well au!nticat$ facts1 we see at once ! important "p :i* e>?quakes h play$ z ag5ts work+ geological *anges4 ,ev5 9 ! n9ete5? c5tury long tracts ( coa/1 z 9 ,*ili & ,new ,zeal&1 h be5 rais$1 :il/ o!r areas1 l ! ,delta ( ! ,indus1 h be5 sunk4 ,sir ,h4 ,b>tle ,fr]e1 speak+ ab\t ! di/urbance :i* took place 9 8 latt] region 9 #ahai1 rem>ks t all ! canals drawn f ! ,fullalee ,riv] ceas$ to run = ab\t ?ree days1 probably indicat+ a g5]al upheaval ( ! l[] "p ( ! canal4 ,9 consequ5ce ( ! e>?quakes 9 =m] times x is n unlikely t wat]-c\rses h ceas$ to fl[1 wat] has decreas$ 9 wells1 & di/ricts h be5 depopulat$4#gb ,sometimes ^! *anges h tak5 place gradually & sometimes ) viol5ce4 ,m\nta9s h be5 toppl$ ov]1 valleys h be5 fill$1 cities h be5 subm]g$ or buri$4 ,) ! records ( ^! convulsions be=e u1 we see t seismic en]gy yet exhibits a t]rible activity 9 *ang+ ! features ( ! globe4 ,reason ( ^! movem5ts4--,to =mulate a s+le reason = ^! cata/rophes w\ld be difficult4 ,:]e !y are ( ! nature ( l&slips1 or mat]ials h be5 dislodg$ f m\nta9 sides1 ! cause is evid5tly ! sudd5 movem5t ( ?is gr\nd act+ ^u /rata n held toge!r 9 a suffici5tly /able condition4 ,a simil> explanation may be giv5 = ! sudd5 elevations or depressions ( /rata 9 a di/rict remov$ f ! c5tre :]e ! di/urbance _h its orig94 ,! seismic ef=t exhibits itself 9 a c]ta9 area r\nd its orig9 z a sudd5 pu%1 & by ?is pu%1 /rata are fractur$ & caus$ to move relatively to ea* o!r4 ,at or ne> to ! orig9 ( an e>?quake x might be argu$ t x 0 ! sudd5 fall+ ( rocky /rata t[>ds a position ( /able equilibrium t caus$ ! %ak+1 & 9 su* a case ! movem5ts ref]r$ to may be reg>d$ z ! cause r ?an ! effect ( an e>?quake4 ,a subject closely connect$ ) ! sudd5 dislocation ( /rata1 is ! production ( second>y or consequ5t e>?quakes1 due to ! di/urbance ( gr\nd 9 a critical /ate 7see p4 #bdh74 ,,*apt] ,,ix4 ,,di/urbances ,,9 ,,! ,,ocean4 ,sea vibrations--,cause ( vibratory bl[s--,sea waves3 ,prec$+ e>?quakes2 ,succe$+ e>?quakes--,magnitude ( waves--,waves z record$ 9 c\ntries di/ant f ! orig9--,records on tide gauges--,waves )\t e>?quakes--,cause ( waves--,ph5om5a difficult ( explanation--,velocity ( propagation--,dep? ( ! ocean--,examples ( calculations--,comp>ison ( velocities ( e>?quake waves ) velocities :i* ought to exi/ f ! kn[n dep? ( ! ocean4 ,sea vibrations4--,:il/ resid+ 9 ,japan ,i h _h _m opportunities ( conv]s+ ) p]sons :o _h exp]i5c$ e>?quakes :5 on bo>d %ips1 & x has (t5 happ5$ t ^! same e>?quakes h be5 record$ on ! %ore4 ,= example1 at ! "t ( e mod]ately sev]e e>?quake :i* has %ak5 ,yokohama1 ! same di/urbance has be5 felt on bo>d ! %ips ly+ 9 ! adjo9+ h>b\r4 ,9 "s cases ! effect _h be5 z if ! %ip 0 gr\nd+2 9 o!rs1 z if a numb] ( %>p j]ks 7 be+ giv5 to ! cable4 ,! effect produc$ ^u a man-(-w> ly+ 9 ! ,yokohama h>b\r on ! ev5+ ( ,m>* #aa1 #ahha1 0 describ$ to me z a #8viol5t irresi/ible %ak+4' ,vessels eighty miles at sea h record$ & tim$ %ocks :i* 7 felt l sudd5 bl[s4 ,^! 7 accompani$ by a noise describ$ z a #8dull rattle l ?und]4' ,9 none ( ! cases "h quot$ 0 any di/urbance ( ! wat] obs]v$4 ,! great e>?quake ( ,lisbon 0 felt by vessels on ! ,atlantic1 fifty miles away f %ore4 ,on ,febru>y #aj1 #agaf1 ! vessels 9 ! h>b\r ( ,new ,pisco 7 s viol5tly %ak5 t bo? ropes & ma/s 7 brok51 & yet no motion 9 ! wat] 0 obs]v$4 ,"s h describ$ ^! %ocks l ^? :i* w\ld be produc$ by ! sudd5 dropp+ ( l>ge masses ( balla/ 9 ! hold ( ! vessel4 ,o!r cases are kn[n :]e rigg+ 0 damag$1 & ev5 cannon h be5 j]k$ up & d[n f ! decks on :i* !y re/$4 ,cause ( vibratory bl[s4--,f ! rattl+ s\nd :i* has accompani$ "s ( ^! subm>9e %ocks1 _m ( :i*1 x may be rem>k$1 h nev] be5 record$ z e>?quakes ^u neighb\r+ %ores1 x does n seem improbable t !y may h be5 ! result ( ! sudd5 cond5sation ( volumes ( /eam produc$ by subm>9e volcanic eruptions4 ,z confirmatory ( ?is supposition we h ! fact1 t _m ( ! m>9e di/urbances :i* might be call$ #8sea-quakes1' h be5 obs]v$ 9 places :i* are close to1 or 9 ! l9e (1 volcanic v5ts4 ,?us1 ,m4 ,daussy1 :o has paid special att5tion to ?is subject1 has collect$ evid5ce to %[ t a l>ge numb] ( %ocks h be5 felt by vessels 9 t portion ( ! ,atlantic betwe5 ,cape ,palamas1 on ! we/ coa/ ( ,africa1 & ,cape ,/4 ,roque1 on ! ea/ coa/ ( ,s\? ,am]ica4#gc ,"s ( ! vessels only felt %ocks & trembl+s1 b o!rs saw smoke1 & "s ev5 collect$ float+ a%es4 ,9 consid]+ ! subm>9e %ocks ( ?is p>ticul> area1 we mu/ be> 9 m9d t x lies 9 ! l9e ( ,icel&1 ! we/ coa/ ( ,scotl&1 ! ,azores1 ,can>ies1 ,cape de ,v]d ,isl&s1 ,/4 ,hel5a1 & o!r places1 all ( :i*1 if n at pres5t 9 volcanic activity1 %ew evid5ce ( hav+ be5 s )9 rec5t times4 ,! connection betwe5 volcanic action & e>?quakes w be aga9 ref]r$ to4 ,sea waves4--,al?\gh 9 ! above-m5tion$ in/ances sea waves h n be5 notic$1 x is by no means uncommon to f9d t de/ructive e>?quakes h be5 accompani$ by waves ( an enorm\s size1 :i*1 if ! e>?quake has orig9at$ b5ea? ! sea1 h1 subsequ5tly to ! %ak+1 roll$ 9 ^u ! l&1 to create m deva/ation ?an ! actual e>?quake4 ,x may1 h[ev]1 be m5tion$ t a few exceptional cases exi/ :5 x is said t ! sea wave has prec$$ ! e>?quake1 z1 = example1 at ,smyrna1 on ,septemb] #h1 #aheb4 ,aga91 at ! e>?quake 9 ,/4 ,?omas1 9 #ahfh1 x is said t ! wat] rec$$ %ortly be=e ! fir/ %ock4 ,:5 x return$1 aft] ! second %ock1 x 0 suffici5t to ?r[ ! ,u4,s4 %ip #8,monagahela' high & dry4#gd ,ano!r ,am]ican %ip1 ! #8,wat]ee1' 0 also lo/ 9 #ahfh by be+ swept a qu>t] ( a mile inl& by ! sea wave :i* inundat$ ,arequippa4 ,mu* ( ! great de/ruction :i* occurr$ at ! "t ( ! great ,lisbon e>?quake 0 due to a s]ies ( great sea waves1 ?irty to sixty feet high] ?an ! highe/ tide1 :i* swamp$ ! t[n4 ,^! came 9 ab\t an h\r aft] ! t[n _h be5 %att]$ by ! motion ( ! gr\nd4 ,! fir/ motion 9 ! wat]s 0 _! )drawal1 :i* 0 suffici5t to completely uncov] ! b> at ! m\? ( ! ,tagus4 ,at ,cadiz1 ! fir/ wave1 :i* 0 ! greate/1 is said to h be5 sixty feet 9 height4 ,=tunately ! deva/at+ effect :i* ?is w\ld h produc$ 0 p>tially w>d$ (f by cliffs4 ,at ! "t ( ! ,jamaica e>?quake 7#afib7 ! sea drew back = a di/ance ( a mile4 ,9 ,s\? ,am]ica sea waves are common accompanim5ts ( l>ge e>?quakes1 & !y are reg>d$ ) m fe> ?an ! actual e>?quakes4 ,on ,octob] #bh1 #agbd1 ,lima 0 de/roy$1 & on ! ev5+ ( t day ! sea rose 9 a wave eighty feet ov] ,callao4 ,out ( tw5ty-?ree %ips 9 ! h>b\r1 n9ete5 7 sunk1 & f\r o!rs 7 c>ri$ f> inl&4 ,! fir/ movem5t :i* is usually obs]v$ is a draw+ back ( ! wat]s1 & ?is is s well kn[n to prec$e ! inru% ( l>ge waves1 t _m ( ! inhabitants 9 ,s\? ,am]ica h us$ x z a timely w>n+ to escape t[>ds ! hills1 & save !mselves f ! t]rible reaction :i*1 on m ?an "o occasion1 has s quickly foll[$4 ,at ,cald]a1 ne> to ,copiapo1 on ,may #i1 #ahgg1 :i* 0 ! "t :5 ,iquique 0 deva/at$1 ! fir/ motion :i* 0 obs]v$ 9 ! sea 0 t x sil5tly drew back = ov] #bjj feet1 aft] :i* x rose z a wave ov] five feet high4 ,at "s places ! wat] came 9 z waves f tw5ty to eighty feet 9 height4 ,at ,talcahuano1 on ! coa/ ( ,*ili1 9 #ahce1 !re 0 a repetition ( ! ph5om5a :i* accompani$ ! de/ruction ( ,p5co 9 #agcj & #agea4 ,ab\t =ty m9utes aft] ! fir/ %ock1 ! sea sudd5ly retir$4 ,soon aft]w>ds1 h[ev]1 x return$ 9 a wave tw5ty feet high1 ! reflex ( :i* swept ev]y?+ t[>ds ! sea4 ,^! ph5om5a 7 repeat$ ?ree times4#ge ,:5 ,callao & ,lima 7 de/roy$1 9 #agdf1 ! sea fir/ drew back1 !n came 9 z waves1 f\r or five m9utes aft] ! e>?quake4 ,altoge!r1 betwe5 ,octob] #bh & ,febru>y #bd1 #dea %ocks 7 c\nt$4 ,at "o "t ! sea came 9 eighty feet above its usual level4 ,"o acc\nt says t ! l>ge waves came 9 =ty-"o & a half h\rs aft] ! fir/ %ock1 & sev5te5 & a half h\rs aft] comp>ative tranquillity _h prevail$4#gf ,at ! eruption ( ,monte ,nuovo1 ne> ,naples1 9 ,septemb] #bg1 #aech1 ! wat] drew back =ty feet1 s t ! :ole gulf ( ,baja became dry4 ,9 #afif1 at ! "t ( ! ,catanian e>?quake1 ! sea is said to h gone back #b1jjj fa?oms4 ,in/ances are record$ :]e ! sea has rec$$ sev]al miles4 ,! "t tak5 = ! fl[+ back ( ! sea is usually v diff]5t4 ,sometimes x has only be5 five or six m9utes1 :il/ at o!r times ov] half an h\r1 & !re are records :]e ! "t is said to h be5 /ill long]4 ,?us1 at ! e>?quake ( ,santa 7,june #ag1 #afgh71 ! sea is /at$ to h gone z f> back z ! eye c\ld rea*1 & did n rise aga9 = tw5ty-f\r h\rs1 :5 x flood$ ev]y?+4 ,9 #afij at ,pisco ! sea w5t back two miles1 & did n return = ?ree h\rs4 ,:5 x returns x does s ) viol5ce1 & examples ( ! heights to :i* x may rea* h be5 giv54 ,! greate/ sea wave yet record$1 accord+ to ,fu*s1 is "o :i*1 on ,octob] #f1 #agcg1 broke on ! coa/ ( ,lupatka1 #baj feet 9 height4 ,!re are1 h[ev]1 cases kn[n :]e ! sea has return$ z gradually z x w5t out4 ,?us1 on ,decemb] #d1 #ahed1 :5 ,acapulco 0 de/roy$1 ! sea is said to h return$ z g5tly z x w5t out4 ,:5 sea waves h travell$ long di/ances f _! orig91 z1 = in/ance1 :5ev] a ,s\? ,am]ican wave crosses ! ,pacific to ,japan1 ! ph5om5a :i* are obs]v$ are l ^? :i* 7 obs]v$ at ,acapulco2 ! sea falls & rises1 at int]vals ( f t5 m9utes to half an h\r1 to heights ( f six to t5 feet1 )\t ! slighte/ appe>ance ( a wave4 ,its ph5om5on is l t ( an unusually high tide1 :i* repeats itself sev]al times p] h\r4 ,ev5 if we wat* di/ant rocks ) a telescope1 al?\gh ! surface ( ! ocean may be z smoo? z ! surface ( a mirror1 !re is n ! slighte/ visible evid5ce ( :at is popul>ly call$ a wave4 ,! sea be+ once set 9 motion x cont9ues to move z waves ( oscillation = a consid]able "t4 ,9 #ahgg1 z obs]v$ 9 ,japan1 ! motion cont9u$ = ne>ly a :ole day4 ,! p]iod & amplitude ( ! rise & fall 7 v>iable1 usually x quickly rea*$ a maximum1 & !n di$ out gradually4 ,z obs]v$ 9 a self-record+ tide gauge at ,san ,francisco1 ! di/urbance la/$ = ab\t f\r days4 ,a diagram ( ?is is "h giv54 ,9 its g5]al appe>ance x is v simil> to ! records ( o!r e>?quake waves4 ,! l>ge waves repres5t ! usual six h\rs rise & fall ( ! tides2 usually ^! are fairly smoo? curves4 ,sup]impos$ on ! l>ge waves are ! small] zigzag curves ( ! e>?quake di/urbance1 la/+ ) great] or less int5sity = sev]al days4 ,z ^! curves are drawn to scale--horizontally = h\rs1 & v]tically "o fif? in* to ! foot1 to %[ ! ext5t ( ! rise & fall--!y w be easily und]/ood4 ,sometimes1 z 9 ! pres5t example1 ! fir/ movem5t 9 ! wat]s is t ( an incom+ wave4 ,9 _m in/ances1 h[ev]1 ?is obs]vation may be due to ! sl[ & m g5tle ph5om5a ( ! previ\s draw+ out ( ! wat]1 :i* 9 a /eep wa/e1 or :5 ! wat] is r\gh1 w\ld be difficult to obs]ve1 n hav+ be5 rem>k$4 ,! di/ance to :i* ^! sea waves h ext5d$ has usually be5 exce$+ly great4 ,illu/ration3 ,,fig4 #bh4--,record ( ,tide ,gauge at ,port ,po9t1 ,san ,francisco4 ,%[+ ,e>?quake ,waves ( ,may #ahgg4 ,! sea wave ( ! ,iquique e>?quake ( ,may #i1 #ahgg1 l _m ( its pr$ecessors1 0 felt across ! bas9 ( ! :ole ,pacific1 f ,new ,zeal& 9 ! s\?1 to ,japan & ,kams*atka 9 ! nor?4 ,& b = ! int]v5tion ( ! ,eurasian & ,am]ican cont95ts w\ld h made itself appreciable ov] ! surface ( ! :ole ( our globe4 ,at places on ! ,s\? ,am]ican coa/1 x has be5 /at$ t ! height ( ! waves v>i$ f tw5ty to eighty feet4 ,at ! ,samoa ,isl&s ! heights v>i$ f six to twelve feet4 ,9 ,new ,zeal& ! sea rose & fell f ?ree to tw5ty feet4 ,9 ,au/ralia ! heights to :i* ! wat] oscillat$ 7 simil> to ^? obs]v$ 9 ,new ,zeal&4 ,9 ,japan x rose & fell f five to t5 feet4 ,9 ?is latt] c\ntry1 ! ph5om5a ( sea waves :i* foll[ a de/ructive e>?quake on ! ,s\? ,am]ican coa/ are s well kn[n t old resid5ts h writt5 to ! local pap]s ann\nc+ ! probability ( su* occurr5ces hav+ tak5 place "s tw5ty-five h\rs previ\sly 9 ,s\? ,am]ica4 ,9 ?is way news ( great calamities has be5 anticipat$1 details ( :i* only arriv$ "s weeks subsequ5tly4 ,j z ! de/ructive e>?quakes ( ,s\? ,am]ica h ann\nc$ !mselves 9 ,japan1 9 a l mann] ! de/ructive e>?quakes ( ,japan h ann\nc$ !mselves ^u ! tide gauges ( ,cali=nia4 ,simil>ly1 b n s frequ5tly1 di/urbances %ake ! o!r oceans ( ! _w4 ,= example1 ! great e>?quake ( ,lisbon propagat$ waves to ! coa/s ( ,am]ica1 tak+ on _! j\rney n9e & a half h\rs4 ,sea waves )\t e>?quakes4--,sometimes we get great sea waves l abnormal tides occurr+ )\t any acc\nt ( contemporane\s e>?quakes4 ,al?\gh e>?quakes h n be5 record$1 ^! ill und]/ood ph5om5a are usually attribut$ to su* movem5ts4 ,sev]al examples ( ^! are giv5 by ,mallet4 ,?us1 at #aj ,a4,m4 on ,m>* #b1 #ahef1 ! sea rose & fell = a consid]able di/ance at _m places on ! coa/ ( ,york%ire4 ,at ,:itby1 ! tide 0 describ$ ebb+ & fl[+ six times p] h\r1 & ?is to su* a di/ance t a vessel ent]+ ! h>b\r 0 alt]nately afloat & agr\nd4 ,9 #agfa1 on ,july #ag1 a simil> ph5om5a 0 obs]v$ at ! same place4 ,a l occurr5ce took place at ,kilmore1 9 ! c\nty ( ,wex=d1 on ,septemb] #af1 #ahfd1 :5 ! wat] ebb$ & fl[$ sev5 times 9 ! c\rse ( two h\rs & a half4 ,^! tides1 :i* appe> to h tak5 ab\t five m9utes to rise & five m9utes to fall1 7 se5 by an obs]v] approa*+ f ! we/ z six di/9ct ridges ( wat]4 ,! g5]al "* ( ! ph5om5a appe>s to h be5 v simil> to t :i* 0 produc$ at ! same place by ! ,lisbon e>?quake ( #agee2 & ! op9ion ( ^? :o saw & wrote ab\t _! occurr5ce 0 t x 0 due to an e>?quake di/urbance4 ,su* ph5om5a are n uncommon on ! ,wex=d coa/1 :]e !y are popul>ly kn[n z #8dea? waves1' probably 9 consequ5ce ( ! lives :i* h be5 lo/ by ^! sudd5 inundations4 ,!y h also be5 obs]v$ 9 o!r p>ts ( ,irel&1 ! nor?-ea/ coa/ ( ,engl&1 & 9 _m p>ts ( ! globe4 ,!y w be aga9 ref]r$ to "u ! head ( e>? pulsations4 ,cause ( sea waves4--,mallet1 :o 9 8 report to ! ,briti% ,association 9 #aheh1 writes ^u ?is la/-m5tion$ occurr5ce at consid]able l5g?1 :il/ admitt+ t _m may h orig9at$ f e>?quakes1 he ?9ks x sc>cely probable t an e>?quake bl[1 suffici5tly p[]ful to h produc$ waves l ^? obs]v$ at ,kilmore1 %\ld n h be5 felt g5]ally ?r\gh\t ! s\? ( ,irel&4 ,he1 !re=e1 sugge/s t sometimes waves l ! above might be produc$ by an und]wat] slippage ( ! mat]ial =m+ ! face ( a subm>9e bank1 ! slope ( :i* by degradation & deposition1 produc$ by curr5ts1 _h rea*$ an angle beyond ! limits ( repose ( ! mat]ial ( :i* x 0 =m$4 ,mallet does n insi/ ^u ! exi/5ce ( ^! subm>9e l&slips1 b only sugge/s _! exi/5ce z a means ( expla9+ c]ta9 abnormal sea waves :i* d n appe> to h be5 accompani$ by e>?quakes4 ,9 ! g5]ality ( cases sea waves are accompani$ by e>?quakes1 b x may (t5 happ5 t ! connection betwe5 ! two is difficult to cle>ly e/abli%4 ,"o simple explanation = ! orig9 ( waves occurr+ ) e>?quakes1 is1 t 9 consequ5ce ( ! e>?quake a l>ge volume ( wat] sudd5ly f9ds its way into cavities :i* h be5 op5$1 ! di/urbance produc$ by ! inru% giv+ rise to waves4 ,a second explanation is1 t ! l& along a %ore is caus$ by an e>?quake to oscillate upw>ds1 ! wat] runn+ (f to rega9 its level4 ,a supposition l ?is is negativ$ by ! fact t ^! di/urbances are felt f> away f ! *ief di/urbance1 on small isl&s4 ,also1 x may be add$1 t ! :ole di/urbance appe>s to approa* ! l& f ! sea1 & n 9 ! opposite direction4 ,?us1 9 ! e>?quake ( ,oahu 7,febru>y #ah1 #ahga71 x 0 rem>k$ t ! %ock 0 fir/ felt by ! %ips f>!/ f ! l&4#gg ,ano!r sugge/ion is t ! waves are due to a sudd5 heav+ up ( ! bottom ( ! ocean4 ,if ?is lift+ took place sl[ly1 !n ! fir/ result w\ld be t ! wat] situat$ ov] ! c5tres ( di/urbance w\ld fl[ away radially 9 all directions f above ! area ( di/urbance4 ,if1 h[ev]1 ! subm>9e upheaval took place ) great rapidity1 say by ! sudd5 evolution ( a l>ge volume ( /eam develop$ by ! entry ( wat] into a volcanic v5t1 z ! wat] 0 heap$ above ! di/urb$ area1 wat] might run 9 radially t[>ds ?is spot4 ,suppos+ a prim>y wave to be =m$ 9 ! ocean by any su* causes1 !n ! fall+ ( ?is w cause a second wave to be =m$1 exi/+ z a r+ r\nd ! fir/ "o4 ,! comb9$ action ( ! fir/ & second wave w =m a ?ird "o1 & s ! di/urbance1 />t+ f a po9t1 w radiate 9 broad5+ circles4 ,dur+ ! up & d[n motion ( ^! waves1 ! en]gy :i* is imp>t$ to any p>ticle ( wat] w1 on acc\nt ( ! "w :i* x has to d 9 displac+ its neighb\rs1 by frictional resi/ance1 gradually gr[ less & less1 until x f9ally dies away4 ,! waves :i* are ! result ( ?is motion w also gr[ less & less4 ,if a s]ies ( sea waves 7 produc$ by a s+le di/urbance1 we see t ^! w be ( unequal magnitude4 ,n[1 = small waves1 ! velocity ) :i* !y travel dep5ds ^u ! squ>e root ( _! l5g?s2 b ) l>ge waves1 l e>?quake waves1 ! velocity dep5ds ^u ! squ>e root ( ! dep? ( wat]1 & ^! latt] travel m quickly ?an ! =m]4 ,if1 !re=e1 we h a s]ies ( di/urbances ( unequal magnitude produc+ sea waves1 :i*1 f ! s]ies ( %ocks :i* h be5 felt ^u %ores subsequ5tly invad$ by waves1 seems 9 all probability (t5 to h be5 ! case1 x is n unlikely t ! waves ( an e>ly di/urbance may be ov]tak5 & int]f]$ ) by a s]ies :i* foll[$4 ,^! consid]ations help u to und]/& ! appe>ance ( ! records on our tide gauges1 & also ! ph5om5a obs]v$ by ^? :o h record$ tidal waves z !y swept inw>ds ^u ! l&4 ,= in/ance1 we und]/& ! reason :y sea waves1 z obs]v$ at places at diff]5t di/ances f ! orig9 ( a di/urbance1 %\ld be ( diff]5t heights4 ,we also see an explanation = ! fact t small waves %\ld sometimes appe> to be int]polat$ betwe5 l>ge ones1 & t ^! %\ld occur at v>y+ int]vals4 ,! fact t :5ev] a wave is produc$1 a c]ta9 quantity ( wat] mu/ be drawn f ! level :i* surr\nds x1 9 ord] t x %\ld be =m$1 expla9s ! ph5om5a t ! sea is (t5 obs]v$ fir/ to draw back4 ,out 9 ! op5 ocean x is drawn f ! holl[ betwe5 two waves4 ,z has be5 po9t$ out by ,d>w91 x is l ! draw+ ( ! wat] f ! %ore ( a riv] by a pass+ /eam]4 ,! diff]5ce 9 ! height ( waves1 z obs]v$ at places ly+ close to ea* o!r1 is probably due to ! configuration ( ! coa/1 ! int]f]5ce ( outly+ isl&s1 reefs1 c4--causes :i* w\ld produce simil> effects 9 ! height ( tide4 ,z a wave approa*es %all[ wat] x gradually increases 9 height1 its front slope becomes /eep1 & its re> slope g5tle1 until f9ally x topples ov] & breaks4 ,?is increas+ 9 height ( waves is no d\bt connect$ ) ! de/ruction ( ,talcahuano & ,callao1 :i* are situat$ at ! head ( %all[ bays4 ,valp>aiso1 :i* is on ! edge ( deep wat]1 has nev] be5 ov]:elm$4#gh ,ano!r case t5d+ to produce anomalies 9 ! "* ( waves w\ld be _! reflection & mutual int]f]5ce1 ! reflections due to ! configuration ( ! ocean b$ & coa/ l9es4 ,! complete ph5om5a :i* may accompany a viol5t subm>9e di/urbance are z foll[s3-- ,by ! initial impulse ( explosion or lift+ ( ! gr\nd1 a #8great sea wave' is g5]at$1 :i* travels %orew>ds ) a velocity dep5d5t ^u its size & ! dep? ( ! ocean4 ,at ! same in/ant1 a #8s\nd wave' may be produc$ 9 ! air1 :i* travels at a quick] rate ?an ! #8great sea wave4' ,a ?ird wave :i* is produc$1 is an #8e>? wave1' :i* w rea* ! %ore ) a velocity dep5d5t on ! int5sity ( ! impulse & ! ela/icity ( ! rocks ?r\gh :i* x is propagat$4 ,?is latt]1 :i* travels ! fa/e/1 may c>ry on its back a small #8=c$ sea wave4' ,on rea*+ ! %ore & pass+ inl&1 ?is #8e>? wave' w cause a slight recession ( ! wat] z ! #8=c$ sea wave' slips f its back4 ,z ^! #8=c$ sea waves' travel !y w give bl[s to %ips b5ea? :i* !y may pass1 be+ transmitt$ f ! bottom ( ! ocean to ! bottom ( ! %ips l s\nd waves 9 wat]4 ,at ! "t ( small e>?quakes1 produc$1 = example1 by ! explosion ( small quantities ( wat] ent]+ volcanic fissures1 or by ! sudd5 cond5sation ( /eam f su* a fissure ent]+ ! ocean1 aque\s s\nd waves are produc$1 :i* cause ! rattl+ & vibrat+ j>s s (t5 notic$ on bo>d %ips4 ,ph5om5a difficult ( explanation4--,al?\gh we c 9 ?is way expla9 ! orig9 & ph5om5a ( sea waves1 we mu/ rememb]1 z ,kluge has po9t$ out1 t x is n ! simple backw>d & =w>d movem5t ( ! gr\nd :i* produces sea waves1 & t ! majority ( e>?quakes :i* h occurr$ 9 volcanic coa/s h be5 unaccompani$ by su* ph5om5a4 ,out ( #ae1jjj e>?quakes obs]v$ on coa/ l9es1 only #abd 7 accompani$ by sea waves4#gi ,out ( #a1jih e>?quakes catalogu$ by ,p]rey = ! we/ coa/ ( ,s\? ,am]ica1 only n9ete5 are said to h be5 accompani$ by movem5ts 9 ! wat]s4 ,accord+ to ! #8,geographical ,magaz9e' 7,augu/ #ahgg1 p4 #bjg71 x w\ld seem t out ( sev5ty-"o sev]e e>?quakes :i* h occurr$ s9ce ! ye> #aejj ^u ! ,s\? ,am]ican coa/ _m h be5 accompani$ by sea waves4 ,d>w9 also rem>ks1 :5 speak+ ( ,s\? ,am]ica1 t almo/ e l>ge e>?quake has be5 accompani$ by consid]able agitation 9 ! neighb\r+ sea4#hj ,on ,april #b1 #ahea1 :5 _m t[ns 9 ,*ili 7 de/roy$1 ! sea 0 n di/urb$4 ,at ! "t ( ! great e>?quake ( ,new ,zeal& 7,june #bc1 #ahee71 al?\gh all ! %ocks came f ! sea1 yet !re 0 no flood4 ,! small %ock ( ,febru>y #ad1 h[ev]1 0 accompani$ by a motion 9 ! sea4 ,to ^! examples1 :i* h be5 *iefly drawn f ! writ+s ( ,fu*s1 mu/ be add$ ! fact t ! great] numb] ( di/urbances :i* are felt 9 ! nor?-ea/]n "p ( ,japan1 al?\gh !y emanate f b5ea? ! sea1 d n produce any visible sea waves4 ,!y are1 h[ev]1 suffici5t to cause a vibratory motion on bo>d %ips situat$ ne> _! orig94 ,ano!r po9t ref]r$ to by ,fu*s1 z difficult ( explanation1 is1 t ! wat]1 :5 x draws back1 (t5 does s ) extreme sl[ness1 & f>!r1 9 "s in/ances1 x has n return$ to its orig9al level4 ,t ! sea might be drawn back = a p]iod ( fifte5 or ?irty m9utes is intelligible1 :5 we consid] ! great l5g? ( ! waves :i* are =m$4 ,cases :]e x has retir$ = sev]al h\rs or days1 & :5 its orig9al level is alt]$1 appe> only to be explicable on ! assumption ( m or less p]man5t *anges 9 ! levels ( ! gr\nd4 ,= example1 9 ! e>?quake ( #ahee :i* %ook ,new ,zeal&1 ! :ole s\!rn portion ( ! nor!rn isl& 0 rais$ sev]al feet4 ,^! sudd5 alt]ations 9 ! levels ( coa/ l9es h already be5 ref]r$ to4 ,o!r po9ts :i* are difficult to und]/& are ! occurr5ce ( di/urbances 9 ! sea at ! "t ( feeble e>?quakes1 & ) e>?quakes occurr+ 9 di/ant places4 ,z examples ( su* occurr5ces1 ,fu*s quotes ! foll[+3 #8,on ,may #af1 #ahej1 at #d4bh ,a4,m41 an e>?quake took place 9 ,pe/h1 & at #g4cj a motion 0 obs]v$ 9 ! sea at ,livorno4 ,aga91 at ! "t ( ! e>?quake ( ,decemb] #ai1 #ahej1 :i* %ook ,heliopolis1 a flood sudd5ly came 9 ^u ,*]b\rg4' ,may n ^! ph5om5a be ! result ( an e>? pulsation1 :i* produc$ an e>?quake at "o po9t1 & a sea wave at ano!r8 ,equally difficult to und]/& are ! obs]vations :5 ! di/urbance 9 ! sea has occurr$ sev]al h\rs aft] an e>?quake2 z1 = in/ance1 at ,batavia1 9 #aheb1 :5 !re 0 an int]val ( two h\rs2 & to ?is mu/ be add$ ! obs]vations :]e ! motion ( ! sea has prec$$ t ( ! e>?quake--z1 = in/ance1 9 #aheb1 at ,smyrna4 ,:il/ recognis+ ! fact t x is possible to sugge/ explanations = _m ( ^! anomalies1 we mu/ also be> 9 m9d t !y are1 g5]ally speak+1 exceptional1 &1 9 "s in/ances1 may possibly be due to errors 9 obs]vations4 ,velocity ( propagation ( sea waves1 & dep? ( ! ocean4--,x has long be5 kn[n to physical sci5ce t ! velocity ) :i* a giv5 wave is propagat$ along a tr\gh ( uni=m dep?1 holds a relation to ! dep? ( ! tr\gh4 ,if v is ! velocity ( ! wave1 & h ! dep? ( ! tr\gh1 ?is relation may be express$ z foll[s3-- v#b 7v7 h ---------- or h 7------7#b g 7k7 ,:]e g #cbai & k #efga4 ,x w be obs]v$ t ^! two =mul 7! fir/ ( :i* is kn[n z ,russell's =mula1 & ! second z ,airy's7 are practically id5tical4 ,! app>5t diff]5ce is 9 ! av]age value assign$ to ! con/ant4 ,= l>ge waves su* z we h to deal )1 x w\ld be necess>y1 if we 7 desir\s ( great accuracy1 to increase ! value ( h by "s small fraction ( itself4 ,we might also make all[ance = ! diff]5t values ( g1 accord+ to our position on ! e>?'s surface4 ,) ^! =mul at our disposal x is an easy matt]1 aft] hav+ det]m9$ ! velocity ) :i* a wave 0 propagat$1 to det]m9e ! av]age dep? ( ! area ov] :i* x 0 transmitt$4 ,9 mak+ c]ta9 e>?quake inve/igations ! rev]se problem is sometimes useful--namely1 det]m9+ ! velocity ) :i* a sea wave has advanc$ ^u a %[n l9e1 f a k ( ! dep? ( ! wat] 9 :i* x has be5 propagat$4 ,calculations ( ! av]age dep?s ( ! ,pacific1 dep5d5t on ! velocity ) :i* e>?quake waves h be5 propagat$1 h be5 made by _m inve/igators4 ,9 mo/ cases1 h[ev]1 9 consequ5ce ( hav+ assum$ ! wave to h orig9at$ on a coa/ l9e1 :5 ! evid5ce cle>ly %[$ x to h orig9at$ "s di/ance out at sea1 ! calculations :i* h be5 made are op5 to criticism4 ,! av]age dep?s :i* ,i obta9$ = v>i\s l9es across ! ,pacific appe> to be some:at less ?an ! av]age dep? z giv5 by actual s\nd+s4 ,we mu/1 h[ev]1 rememb] t ! common error 9 actual s\nd+s is t !y are usually too great1 x be+ difficult 9 deep-sea s\nd+ to det]m9e :5 ! lead actually rea*es ! bottom4 ,until oceans h be5 m ?or\ghly survey$ ) ! improv$ =ms ( s\nd+ app>atus1 we %all n be able to v]ify ! tru? ( ! results :i* h be5 giv5 to u by e>?quake waves4 ,,examples ,,( ,,calculations ,,on ,,sea ,,waves4 #a4 ,! wave ( #ahed4--,?is wave orig9at$ ne> ,japan1 & x 0 record$ on tide gauges at ,san ,francisco1 ,san ,diego1 & ,a/oria4 ,on ,decemb] #bc1 at #i4ae4 ,a4,m41 a /rong %ock 0 felt at ,simoda 9 ,japan1 :i*1 at #aj o'clock1 0 foll[$ by a l>ge wave ?irty feet 9 height4 ,! ris+ & fall+ ( ! wat] cont9u$ until noon4 ,half an h\r aft]1 ! movem5t became m viol5t ?an be=e4 ,at #b4ae ,p4,m4 ?is agitation decreas$1 & at #c ,p4,m4 x 0 comp>atively sl[4 ,altoge!r !re 7 five l>ge waves4 ,on ,decemb] #bc & #be1 unusual waves 7 record$ ^u ! self-regi/]+ tide gauges at ,san ,francisco1 ,san ,diego1 & ,a/oria4 ,at ,san ,francisco ?ree sets ( waves 7 obs]v$4 ,! av]age "t ( oscillation ( "o ( ! fir/ set 0 ?irty-five m9utes1 :il/ "o ( ! second & ?ird sets 0 almo/ ?irty-"o m9utes4 ,at ,san ,diego ?ree s]ies ( waves 7 also %[n1 b ) av]age times ( oscillation ( f f\r to two m9utes %ort] ?an ! waves at ,san ,francisco4 ,! ,san ,francisco waves appe> to indicate a recurr5ce ( ! same ph5om5a4 ,! record at ,san ,diego %[s :at 0 probably ! effect ( a s]ies ( impulses1 ! heights increas+ to ! ?ird wave1 !n dim9i%+1 !n once m r5ew$1 aft] :i* x di$ away4 ,! result ( calculations bas$ on ^! data 73-- ---------------------------------------- --------------------- ,di/ance ,"t ,velocity ,dep? ( geographical ( 9 feet ocean 9 miles transmissionp] sec4 fa?oms ---- ---------------------------------------- ---------------- h4 m4 ,simoda to ,san #diag #ab #ac #ede #bajj ,diego ,simoda to ,san #debg #ab #ci #ebh #bejj or #bbcj ,francisco ---------------------------------------- --------------------- ,! diff]5ce = ! dep?s 9 ! ,san ,francisco pa? dep5ds :e!r ! l5g? ( ! waves is reckon$ at #baj or #bag miles4 ,! l5g? ( ! waves on ! ,san ,diego pa? 7 #ahf or #aib miles4#ha ,! wave ( #ahfh4--,on ,augu/ #aa1 #ahfh1 a sea wave ru9$ _m cities on ! ,s\? ,am]ican coa/1 & #be1jjj lives 7 lo/4 ,?is wave1 l all ! o!rs1 travell$ ! l5g? & bread? ( ! ,pacific4 ,9 ,japan1 at ,hakodate1 x 0 obs]v$ by ,capta9 ,t4 ,blaki/on1 ,r4,a41 :o v k9dly gave me ! foll[+ acc\nt3 ,on ,augu/ #ae1 at #aj4cj ,a4,m41 a s]ies ( bores or tidal waves comm5c$1 & la/$ until #c ,p4,m4 ,9 t5 m9utes !re 0 a diff]5ce 9 ! sea level ( t5 feet1 ! wat] ris+ above high wat] & fall+ bel[ l[ wat] m>k ) great rapidity4 ,! ord9>y tide is only two & a half to ?ree feet4 ,! di/urbance produc+ ^! waves orig9at$ betwe5 ,iquique & ,arica1 9 ab\t lat4 #ah4bh ,s4 at ab\t #e ,p4,m4 on ,augu/ #ac4 ,9 ,gre5wi* "t ?is w\ld be ab\t #ac;h4 #im4 #djs4 ,augu/ #ac4 ,! arrival ( ! wave at ,hakodate 9 ,gre5wi* "t w\ld be ab\t #ad;h4 #gm4 #fs4 ,augu/ #ad3 t is to say1 ! wave took ab\t #bd;h4 #egm4 to travel ab\t #h1gjj miles1 :i* gives u an av]age rate ( ab\t #eaa feet p] second4 ,^! waves 7 felt all ov] ! ,pacific4 ,at ! ,*a?am ,isl&s !y ru%$ 9 ) su* viol5ce t :ole settlem5ts 7 de/roy$4 ,at ! ,s&wi* ,isl&s ! sea oscillat$ at int]vals ( t5 m9utes = ?ree days4 ,comp>+ ?is wave ) ! "o ( #ahgg we see t "o rea*$ ,hakodate ) a velocity ( #eaa feet p] second1 :il/ ! o!r travell$ ! same di/ance at #eab feet p] second4 ,an acc\nt ( ?is e>?quake wave has be5 giv5 by ,f4 von ,ho*/ett] 7#8b] das ,erdbeb5 9 ,p]u am #ac4 ,augu/ #ahfh und die dadur* v]anlas/5 ,flu?well5 im ,pacifis*5 ,ocean1' ,sitzungsb]i*te d] ,kais]l4 ,akademie d] ,wiss5s*aft51 ,wi5 #eh4 ,bd41 #b4 ,ab?4 #ahfh74 ,f an epitome ( ?is pap] giv5 9 #8,pet]mann's ,geograph4 ,mit!il4' #ahfi1 p4 #bbb1 ,i h drawn up ! foll[+ table ( ! m important results obta9$ by ,f4 von ,ho*/ett]4 ,! wave is assum$ to h orig9at$ ne> ,arica4 ---------------------------------------- ------------------ ,di/ance ,"t ,velocity ,dep? ( sea miles tak5 by 9 feet ocean 9 f ,arica wave p] second feet ---------------------------------------- ------------------ h4 m4 ,valdivia #a1dbj #e #j #dgi #g1adj ,*a?am ,isl&s #e1ebj #ae #ai #fjh #aa1dgb ,lyttleton #f1abj #ai #ah #ecc #h1hch ,newca/le #g1chj #bb #bh #ech #i1jjf ,apia 7,samoa7 #e1gfj #af #b #fjd #aa1cdf ,rapa #d1jeg #aa #aa #faa #aa1eih ,hilo #e1djj #ad #be #eee #i1efh ,honolulu #e1ehj #ab #cg #gdf #ag1bib ---------------------------------------- ------------------ ,calculations on ! same di/urbance are also giv5 by ,j4 ,e4 ,hilg>d4#hb ,assum+ ! orig9 ( ! wave to h be5 at ,arica1 8 results are z foll[s3 ---------------------------------------- -------------------- ,nautical ,di/ance ,"t ( miles ,mean dep? f ,africa transmission p] h\r ( ocean ---------------------------------------- -------------------- miles h4 m4 feet ,san ,diego #d1jcj #aj #ee #cfi #ab1ajj ,=t ,po9t #d1dhj #ab #ef #cdh #aj1hjj ,a/oria #e1jjj #ah #ea #bfe #f1bjj ,kodiak #f1bjj #bb #jj #bhb #g1jjj ,rapa #d1jeg #aj #ed #cgb #ab1bjj ,*a?am ,isl&s #e1ebj #ae #ja #cfh #ab1ajj ,hawaii #e1dfj #ad #aj #che #ac1bjj ,honolulu #e1ehj #ab #ah #ded #ah1ejj ,samoa #e1gfj #ae #ch #cfh #ab1ajj ,lyttelton #f1abj #ai #ja #cbb #i1bjj ,newca/le #i1chj #bb #aj #ccb #i1hjj ,sydney #g1ddj #bc #da #cad #h1hjj ---------------------------------------- -------------------- ,! wave ( #ahgg4--,two sets ( calculations h be5 made ^u ! wave ( #ahgg by ,dr4 ,e4 ,ge9itz ( ,ro/ock4#hc ,! foll[+ table is tak5 f ,dr4 ,ge9itz's second pap]1 9 :i* !re are sev]al modifications ( 8 fir/ results4 ,! orig9 ( ! di/urbance is assum$ to h be5 ne> ,iquique4 ---------------------------------------- ---------------------- ,di/ance ,velocity ,mean ,obs]vation f ,arrival ,"t 9 feet dep? ( /ations ,iquique ( wave tak5 p] ocean geol4 by wavesecond 9 miles fa?oms ---------------------------------------- ---------------------- h4 m4 h4 m4 ,taiohc 7,m>quesa ,isl&s7 #d1jhf #h #dj ,a4,m4 #ab #ae #efch #a1fdg ,apia 7,samoa7 #e1gdj #ab #j #ae #cj #fajd #a1icj ,hilo 7,s&wi* #e1ebf #aj #bd #ad #j #ffgi #b1caj ,isl&s7 ,kahuliu #e1fbh #aj #cj #ad #e #fgeb #b1cfa ,honolulu #e1gab #aj #ej #ad #be #ffig #b1cai ,well+ton 7,new #e1feg #b #dj ,p4,m4 #ah #ae #ebdb #a1dcj ,zeal&7 ,lyttelton #e1fda #b #dh #ah #bc #eaih #a1djj ,newca/le 7,au/ralia7 #f1hjj #b #cb #ah #g #fccj #b1jge ,sydney #f1ghb #b #ce #ah #aj #fcad #b1jfe ,kamie%i 7,japan7 #h1gij #g #bj #bb #ee #fdij #b1ahb ,hakodate #h1gfj #i #be #be #j #eibe #a1hah ,kadsusa #h1ici #i #ej #be #ae #fjdi #a1hie ---------------------------------------- ---------------------- ,! mean dep?s repres5t a mean ( two sets ( calculations1 "o made ) ! aid ( ,airy's =mula1 & ! o!r by ,scott-,russell's =mula4 ,! result ( my own inve/igation ab\t ?is di/urbance1 ! orig9 ( :i*1 by sev]al me?ods ( calculation1 is %[n to h be5 b5ea? ! ocean1 ne> #ga #e we/ long41 & #ba #bb s\? lat41 are giv5 on next page4 ,dr4 ,ge9itz consid]s t 8 calculat$ dep?s ( ! ocean & ^? obta9$ by actual s\nd+s are 9 accordance1 a result :i* is diametrically oppos$ to t :i* ,i h obta9$4 ,?is diff]5ce betwe5 my calculations & ^? ( ,dr4 ,ge9itz1 ,ho*/ett]1 & o!rs1 *iefly re/s on ! orig9 we h assign$ = ! sea waves4 ,dr4 ,ge9itz1 = in/ance1 al?\gh he says t ! orig9 ( ! #ahgg e>?quake 0 n on ! cont95t b to ! we/ 9 ! ocean1 bases all 8 calculations on ! assumption t ! c5trum 0 at or ne> to ,iquique1 & ! "t at :i* t city 0 di/urb$ 0 ! "t at :i* ! waves comm5c$ to spread across ! ocean4 ,?is "t is #h4be ,p4,m4 ,at ?is "t1 h[ev]1 x appe>s t ! waves mu/ h be5 m ?an d\ble ! di/ance betwe5 ! true orig9 & ,iquique1 f ,iquique on _! way t[>ds ! opposite side ( ! ,pacific4 ,introduc+ ?is elem5t into ! v>i\s calculations :i* h be5 made respect+ ! dep? ( ! ,pacific ,ocean z d]iv$ f obs]vations on e>?quake waves--:i* elem5t1 insomu* z ! waves appe> to h come 9 to inundate ! l& "s "t aft] ! %ock1 ne$s to be introduc$--we r$uce ! velocity ( transit ( ! e>?quake wave &1 consequ5tly1 ! resultant dep?s ( ! ocean4 ,key3 ,a ,di/ance f ! orig9 9 miles 7calculat$ 9 great circles7 ,b ,velocity 9 feet p] second ---------------------------------------- -------------------------- ,arrival ,"t ,dep? ,int]val ( wave tak5 ( ! ,height betwe5 ,longitude 9 by ,a ,b ocean ( waves 9 ,gre5wi*wave 9 feet waves m9utes mean "t ---------------------------------------- -------------------------- day h4 m4h4 m4 ,orig9 ( wave #ga #e ,w4 #i #ab #ei ,san ,francisco#abb #cb #aj #b #bhac #bid1eghdih #g1gba #i 94 ,callao #gg #ae #i #ag #i #d #aj #fehbca #a1feg ,iquique #gj #ad #i #ac #ba #j #bb #hgcdh #c1ggj #bj ft4 #bb ,cobija #gj #ba #i #ac #ai #j #bj #hjceb #c1heg #cj ,mejillones #gj #ce #i #ac #bg #j #bh #ajhcci #c1ehg #ce #ae or #de ,*an>al #ga #cd #i #ae #bf #b #bg #deebgb #b1cji #aj ,coquimbo #ga #bd #i #ae #ae #b #af #ejhcbh #c1cfc #cj ,valp>aiso #ga #ch #i #af #af #c #ag #fiecaj #c1jjj ,concepcion #gc #e #i #af #eb #c #ec #ibhcej #c1hbd #ab to #ae ,honolulu #aeg #ee #aj #c #ebad #ece1fidefa #i1hjg #cd to #be #ed ft4 ,hilo #aee #c #aj #c #ead #fe1ejfefcaj1bag #cj or #c or #ae #h #ah or #bg ,kahuliu #aef #dc #aj #c #abad #ace1faaegiaj1dcg ,samoa #aga #da ,w4#aj #c #egad #ehe1ggceff #i1igb #ab ft4 #aj ,taurauga #agf #aa ,e4#aj #h #aeai #afe1faedbg #e1fig ,well+ton #agd #cj #aj #g #bbah #bce1egddde #f1afh #aa #aj ,ak>oa #agb #ei #aj #g #bhah #bie1edbddj #f1jca ,lyttelton #agb #de #aj #g #biah #cje1eehdda #f1jee ,kamei%i #adj #ej #aj #ab #cgbc #chh1hddedi #i1cgh #f #ae ,hakodate #adj #ej #aj #ad #gbe #hh1ggheab #h1afi #g #bj ---------------------------------------- -------------------------- ,9 ,dr4 ,ge9itz's pap] !re are also "s slight diff]5ces 9 ! times at :i* ! e>?quake ph5om5a 7 obs]v$ at v>i\s localities4 ,^!1 h[ev]1 are b ( m9or importance4 ,at ! end ( ! pap] by ,dr4 ,ge9itz two int]e/+ tide gauge records are introduc$1 "o f ,sydney & ! o!r f ,newca/le4 ,^! appe> to %[ a m>k$ diff]5ce 9 ! p]iods ( ! sea waves at ^! two places4#hd ,comp>ison ( velocities ( wave-transit :i* h be5 actually obs]v$1 ) velocities :i* ought to exi/ f :at we "k ( ! dep? ( ! ,pacific by actual s\nd+s4--,f a *>t giv5 9 #8,pet]mann's ,geograph4 ,mit!ilung51' ,b& xxiii4 p4 #afd1 #ahgg1 x is possible to draw approximate sections on l9es 9 v>i\s directions across ! b$ ( ! ,pacific4 ,f ! orig9 ( ! %ock to ,japan 7,kamei%i7 ! l9e w\ld be z foll[s3-- ab\t #g1dda miles #ae1jjj feet deep #a1ajj #ah1jjj #afj #bg1jjj #hj #ab1jjj #fj #f1jjj ,on acc\nt ( ! ,tusc>ora & ,belkap ,deeps ?is w\ld be ! mo/ irregul> l9e ov] :i* ! wave _h to travel4 ,f ! orig9 to ,new ,zeal& 7,well+ton7 ! l9e w\ld be ab\t #e1bgd miles #ae1jjj feet deep4 #cjj #ab1jjj ,f ! orig9 to ,samoa ! l9e w\ld be ab\t #e1ggc miles #ae1jjj feet deep4 ,f ! orig9 to ! ,s&wi* ,isl&s 7,honolulu7 ! l9e w\ld be almo/ #f1fcd miles #ae1jjj feet deep & #fj #ab1jjj ,by ,scott-,russell's rule1 or1 :at is almo/ id5tically ! same1 by ,airy's g5]al =mula1 we c calculate h[ long x w\ld take su* waves z we h be5 speak+ ab\t to travel ov] ! diff]5t portions ( ea* ( ^! l9es1 & by add+ ^! times toge!r we obta9 ! "t tak5 to travel across any "o l9e4 ,i h made ^! calculations1 b z ,i get 9 e case answ]s :i* are too small1 ,i ?9k x unnecess>y to give !m4 ,! actual times tak5 to travel ! di/ances j ref]r$ to 71 ,to ,japan 7,kamei%i7 #bc hr4 #ch m94 ,new ,zeal& 7,well+ton7 #ah #bc ,samoa #ad #eh ,s&wi* ,isl&s 7,honolulu7 #ad #ec ,f ,san ,francisco to ,simoda ! l9e is almo/ #c1efg miles1 #c1jjj fa?oms deep1 #hdj miles1 #b1ejj fa?oms deep1 & #abj miles #a1jjj fa?oms deep4 ,?is gives an av]age dep? ( ab\t #b1hed fa?oms4 ,ba*e calculat$ ! dep? at #b1ejj fa?oms4 ,if we are to consid] t1 because ! sea wave at ,simoda came 9 "s "t aft] ! l& %ock _h be5 felt1 ! orig9 ( ?is e>?quake1 in/ead ( be+ at ,simoda1 0 "s di/ance out at sea1 ?is calculat$ dep? w\ld be r$uc$4 ,,*apt] ,x4 ,,det]m9ation ,,( ,,e>?quake ,,orig9s4 ,approximate det]m9ation ( an ,orig9--,e>?quake-hunt+ 9 ,japan--,det]m9ations by direction ( motion--,direction indicat$ by de/ruction ( build+s--,direction det]m9$ by rotation--,cause ( rotation--,! use ( "t obs]vations--,errors 9 su* obs]vations--,orig9 det]m9$ by ! me?od ( /raight l9es--,! me?od ( circles1 ! me?od ( hyp]bolas1 ! me?od ( co-ord9ates--,haughton's me?od--,diff]5ce 9 "t betwe5 s\nd1 e>?1 & wat] waves--,me?od ( ,seeba*4 ,"o ( ! mo/ practical problems :i* c be sugge/$ to ! seismologi/ is ! det]m9ation ( ! di/rict or di/ricts 9 any giv5 c\ntry f :i* e>?quake di/urbances orig9ate4 ,) a map ( a c\ntry be=e u1 %ad$ ) t9ts ( diff]5t int5sity to indicate ! relative frequ5cy ( seismic di/urbance 9 v>i\s di/ricts1 we at once see ! localities :]e we might dwell ) ! lea/ di/urbance1 & ^? we %\ld seek if we wi% to make obs]vational seismology a /udy4 ,be=e erect+ obs]vatories = ! sy/ematic inve/igation ( e>?quakes 9 a c\ntry1 x w\ld be necess>y = u1 9 "s way or o!r1 to exam9e ! propos$ c\ntry to f9d out ! mo/ suitable di/rict4 ,! special problem ( det]m9+ approximately ! orig9 or orig9s ( a set ( e>?quakes w\ld be giv5 to u4 ,hav+ made ?is prelim9>y inve/igation1 ! next po9t is1 by means ( obs]vatories s arrang$ t !y c\ld always "w 9 conjunction ) ea* o!r1 to det]m9e ! orig9s m accurately4 ,by kn[+ ! orig9 f :i* a set ( %ocks spr+ we "k ! g5]al direction 9 :i* we may expect ! mo/ viol5t di/urbances1 & we c arrange our seismomet]s accord+ly4 ,approximate det]m9ation ( orig9s4--,9 #ahhj ,i obta9$ a tol]ably fair idea ( ! di/ribution ( seismic en]gy ?r\gh\t ,japan1 by compil+ ! facts obta9$ f "s hundr$s ( communications receiv$ f v>i\s p>ts ( ! c\ntry respect+ ! numb] ( e>?quakes t _h be5 felt4 ,! communications 7 replies to lett]s s5t to v>i\s resid5ts 9 ! c\ntry & to a l>ge numb] ( public (fic]s4 ,by tak+ ^! records1 9 conjunction ) ! records made by in/rum5ts1 x 0 asc]ta9$ t 9 ,japan alone !re 7 c]ta9ly #a1bjj %ocks felt dur+ ! ye>1 t is to say1 ?ree or f\r %ocks p] day4 ,! great] numb] ( ^! %ocks 7 felt along ! ea/]n coa/1 comm5c+ at ,tokio1 9 ! s\?1 & go+ nor?w>ds to ! end ( ! ma9 isl&4 ,^! %ocks 7 seldom felt on ! we/ coa/4 ,x appe>$ z if ! c5tral range ( m\nta9s =m$ a b>ri] to _! progress4 ,simil>ly1 ranges ( m\nta9s to ! s\?-we/ ( ,tokio prev5t$ ! %ocks f travell+ s\?w>ds4 ,proce$+ 9 ?is way ! conclusion 0 arriv$ at t ! we/ coa/1 ! s\!rn "p ( ,japan1 & ! isl&s ( ,%ikoku & ,kiu%iu1 _h _! own local e>?quakes4 ,e>?quake-hunt+4--,^! prelim9>y enquiries hav+ %[n t ! nor!rn "p ( ,japan 0 a bett] di/rict = seismological obs]vations ?an ! s\!rn half1 ! next /ep 0 to subject ! nor!rn half to a clos] analysis4 ,?is analysis 0 comm5c$ by s5d+ to all ! important t[ns1 f ?irty to "o hundr$ miles di/ant f ,tokio1 bundles ( po/c>ds4 ,^! 7 entru/$ to ! local gov]nm5t (fices ) a reque/ t ea* week "o ( ^! c>ds w\ld be return$ to ,tokio /at+ ! numb] ( %ocks felt4 ,9 ?is way x 0 quickly discov]$ t ! majority ( %ak+s emanat$ f ! nor? & ea/1 & seldom1 if ev]1 pass$ a heavy range ( m\nta9s to ! s\?4 ,! b>ricade ( po/c>ds 0 !n ext5d$ f>!r nor?w>ds1 ) ! result ( surr\nd+ ! orig9 ( c]ta9 %ocks among/ ! m\nta9s1 :il/ o!rs 7 trac$ to ! sea %ore4 ,by sy/ematically pursu+ e>?quakes x 0 se5 t _m %ocks _h _! orig9 b5ea? ! sea--!y %ook all ! places on ! nor?-ea/ coa/1 b x 0 seldom t !y cross$ ?r\gh ! m\nta9s1 =m+ ! backbone ( ! isl&1 to di/urb ! places on ! we/ coa/4 ,! actual results obta9$ 9 ?ree mon?s by ?is me?od ( work+ are %[n 9 ! accompany+ map1 :i* embraces ! nor!rn half ( ! ma9 isl& ( ,nipon & "p ( ,yezo4 ,! %ad$ portion ( ! map indicates ! m\nta9\s di/ricts1 :i* are trav]s$ by ranges v>y+ 9 height f ab\t #b1jjj & #g1jjj feet4 ,! dott$ l9es %[ ! b\nd>ies ( ! m important gr\ps ( e>?quakes :i* 7 record$4 ,i4 is ! we/]n b\nd>y ( e>?quakes1 :i* at places to ! ea/w>d are usually felt some:at sev]ely4 ,"s ( ^! h be5 felt ! mo/ sev]ely at or ne> ,hakodadi1 :il/ f>!r s\? _! effects h be5 weak4 ,occasionally ! greate/ effect has be5 ne> to ,kamei%i4 ,sometimes ^! e>?quakes t]m9ate along ! we/]n b\nd>ies ( ,,iii4 or ,,iv41 n be+ able to pass ! high range ( m\nta9s :i* sep>ate ! pla9 ( ,musa%i f ,k(u4 ,illu/ration3 ,,fig4 #bi4--,nor!rn ,japan4 ,m\nta9\s di/ricts %ad$ ) oblique l9es4 ,,ii4 is ! b\nd>y ( a %ock conf9$ to ! pla9 :i* surr\nds ,k(u4 ,^! e>?quakes are evid5tly q local4 ,_m ( ! di/urbances h evid5tly orig9at$ b5ea? ! ocean1 hav+ come 9 ^u ! l& 9 ! direction ( ! arr[s ,a or ,b4 ,,iii4 ,?is l9e indicates ! b\nd>y ( a gr\p ( %ocks :i* are (t5 exp]i5c$ 9 ,tokio4 ,^! may come 9 ! directions ,d1 ,e1 or ,f4 ,x is probable t "s ( !m orig9ate to ! ea/w>d ( ,yokohama1 on or ne> to ! opposite p59sula4 ,,iv4 ,v4 & ,,vi4 ,! e>?quakes b\nd$ by ^! l9es probably orig9ate 9 ! directions ,c or ,d4 ,,vii4 ,! e>?quakes b\nd$ by ?is l9e probably come f ! direction ,e4 ,,viii4 ,?is l9e gives u ! b\nd>y ( e>?quakes :i* may come f ! direction ,b4 ,! above b\nd>ies sometimes d n ext5d s f> to ! we/w>d z !y are %[n4 ,at o!r times1 gr\ps l ,v4 & ,,vi4 ext5d f>!r to ! s\?-we/4 ,^! e>?quake b\nd>ies1 :i* s cle>ly %[ ! effects ( high m\nta9s 9 prev5t+ ! ext5sion ( motion1 h be5 drawn up1 n f s+le e>?quakes1 b f a l>ge s]ies ( e>?quakes :i* h be5 plott$ ^u blank maps1 & are n[ b\nd toge!r to =m an atlas4 ,to give an idea ( ! mat]ial ^u :i* ,i h be5 work+1 ,i may /ate t betwe5 ,m>* #a & ,m>* #aj1 #ahhb1 ,i receiv$ records ( no less ?an ?irty-f\r di/9ct %ocks felt 9 di/ricts betwe5 ,hakodate & ,tokio1 & = ea* ( ^! x is q possible to draw a map4 ,9 addition to ! b\nd>ies ( di/urbances giv5 9 ! accompany+ map1 o!r b\nd>ies might be drawn = %ocks :i* 7 m local 9 _! "*4 ,! gr\ps :i* conta9$ ! greate/ numb] ( %ocks are ,,iii41 ,,iv41 ,v41 ,,vi41 & ,,vii4 ,by "w ( ?is description x 0 f\nd t a v important gr\p ( e>?quakes might be /udi$ by a l9e ( /ations comm5c+ at ,saporo 9 ! nor?1 pass+ ?r\gh ,hakodate1 d[n ! ea/ coa/ ( ! ma9 isl&1 to ,tokio or ,yokohama 9 ! s\?4 ,a fur!r aid to ! /udy ( ?is gr\p1 toge!r ) ! /udy ( an important local gr\p1 might be effect$ ) ! help ( a few additional /ations prop]ly di/ribut$ on ! pla9 ( ,musa%i1 :i* surr\nds ,tokio4 ,) ?is example be=e u x w be recognis$ t ! *oice ( sites = a connect$ set ( seismological obs]vatories w (t5 be m or less a special problem4 ,if e>?quake /ations 7 to be plac$ 9 diff]5t directions ar\nd ,tokio )\t prelim9>y inve/igation1 x is q possible t "s ( !m might be s situat$ t !y w\ld seldom if ev] "w 9 conjunction ) ! rema9+ obs]vatories1 & !re=e be ( b little value4 ,& ?is rem>k mu/ equally apply to di/ricts 9 o!r portions ( ! globe4 ,! me?od is crude1 &1 s f> z actual e>?quake orig9s are conc]n$1 x only yields results :i* are approximate4 ,! crud5ess & ! want ( absolut5ess 9 ! results is1 h[ev]1 m ?an c\nt]balanc$ by ! c]ta9ty ) :i* we are enabl$ to express ourselves ) reg>d to su* results z are obta9$4 ,ev5 :5 work+ ) ! be/ in/rum5ts we h at our comm&1 unless we are employ+ "s elaborate sy/em1 ?is me?od ( work+ gives a mo/ valuable *eck ^u our in/rum5tal records1 & enables u to int]pret !m ) great] confid5ce4 ,det]m9ation ( e>?quake orig9s f ! direction ( motion4--,if we assume t an e>?quake is propagat$ f a c5tre z a s]ies ( waves1 9 :i* normal vibrations are conspicu\s1 & obta9 at two localities1 n 9 ! same /raight l9e ) ! orig91 & suffici5tly f> sep>at$ f ea* o!r1 ! direction ( movem5t ( ^! normal motions1 by draw+ l9es p>allel to ^! directions ?r\gh our two /ations1 ! l9es w\ld int]sect at a po9t above ! requir$ orig94 ,if in/ead ( two po9ts we _h ?ree1 or1 bett] /ill1 a l>ge numb]1 ! results we %\ld obta9 ought to be /ill m c]ta94 ,un=tunately1 x seems t e>?quakes seldom orig9ate f a giv5 po9t1 &1 fur!r1 normal motions are n always 7suffici5tly7 prom95t4 ,sometimes1 z has already be5 %[n 9 ! *apt]s on e>?quake motion1 !y may be non-exi/5t4 ,x is probable1 h[ev]1 t difficulties ( ?is sort are m usually associat$ ) non-de/ructive e>?quakes4 ,mallet reg>ds ! de/ructive effects ( an e>?quake z almo/ solely due to normal motions4 ,if ?is be true1 = de/ructive e>?quakes1 ! problem is %orn ( _m ( its difficulties4 ,9 cases :]e normal vibrations are n prom95t1 :]e we h only transv]se vibrations1 motions due to ! int]f]5ce ( normal or transv]se motions1 or directions ( motions due to ! topographical or geological nature ?r\gh :i* ! di/urbance has pass$1 ! det]m9ation ( ! orig9 ( an e>?quake by obs]vations on ! direction 9 :i* ! gr\nd has be5 mov+ appe>s to be a problem :i* is practically )\t a solution4 ,we w1 !re=e1 only consid] ! det]m9ation ( ! orig9 ( ^? e>?quakes :i* h pr$om9at+ directions 9 _! movem5ts1 :i* directions we w consid] z normal ones4 ,! "q :i* is1 !n1 be=e u1 is ! det]m9ation ( ! direction ( ^! normal movem5ts4 ,fir/ ( all we may take ! evid5ce ( our s5ses4 ,9 exceptional cases ^! h giv5 results :i* closely approximate to ! tru?1 b 9 ! majority ( cases su* results are n to be reli$ ^u1 z ! inhabitants ( a t[n w1 = ! same %ock1 give directions correspond+ to all po9ts ( ! compass4 ,mu*1 no d\bt1 dep5ds ^u ! situation ( ! obs]v]1 & mu*1 p]haps1 ^u 8 temp]am5t4 ,if he is sitt+ 9 a room alone1 & is accu/om$ to mak+ obs]vations on an e>?quake1 on feel+ ! e>?quake1 if he conc5trates 8 att5tion on ! direction 9 :i* he is be+ mov$1 8 obs]vations may be ( value4 ,if1 h[ev]1 he is n s situat$1 & 8 att5tion is n ?us conc5trat$1 8 op9ions1 unless ! motion has be5 v decid$ 9 its "*1 are usually ( b little wor?4 ,direction det]m9$ f de/ruction ( build+s4--,:5 an obs]v] fir/ sees a t[n t has be5 p>tially %att]$ by an e>?quake1 all appe>s to be confusion1 & x is difficult to imag9e t 9 su* app>5t *aos we are able to discov] laws4 ,if1 h[ev]1 we take a g5]al view ( ?is de/ruction & comp>e toge!r simil>ly built build+s1 x is possible to discov] t simil> & simil>ly situat$ /ructures h suff]$ 9 a simil> mann]4 ,by c>efully analys+ ! de/ruction we are enabl$ to inf] ! direction 9 :i* ! de/roy+ =ces h act$4 ,x 0 *iefly by obs]v+ ! cracks 9 build+s1 & ! direction 9 :i* bodies 7 ov]?r[n or project$1 t ,mallet det]m9$ ! orig9 ( ! ,neapolitan e>?quake4 ,f ! obs]vations giv5 9 ,*apt] ,,vii4 x w\ld appe> t1 ) de/ructive e>?quakes1 walls :i* are transv]se to ! direction ( motion are mo/ likely to be ov]turn$1 :il/1 ) small e>?quakes1 ^! walls are ! lea/ liable to be fractur$4 ,f a critical exam9ation ( ! g5]al nature ( ! damage done on ! build+s ( a t[n1 e>?quake obs]v]s h %[n t ! direction ( a %ock may (t5 be approximately det]m9$4 ,! direction 9 :i* a body hav+ a regul> =m l a prismatic grave/one or a cyl9drical column is ov]turn$ sometimes gives ! means by :i* we c det]m9e ! direction f :i* a movem5t came4 ,! rotation ( bodies4--,x has (t5 be5 obs]v$ t almo/ all l>ge e>?quakes h caus$ objects l tomb/ones1 obelisks1 *imneys1 c41 to rotate4 ,"o ( ! mo/ natural & at ! same "t mo/ simple explanations is to suppose t dur+ ! %ock !re _h be5 a twi/+1 or backw>d & =w>d screw-l motion 9 ! gr\nd4 ,among/ ! ,italians & ! ,mexicans e>?quakes produc+ an effect l ?is are spok5 ( z #8vorticosi4' ,9 ! ,calabrian e>?quake1 n only 7 bodies l obelisks twi/$ on _! bases1 b /raight r[s ( trees seem to h be5 left 9 int]rupt$ zigzags4 ,^! latt] ph5om5a h be5 expla9$ ^u ! assumption ( ! int]f]5ce ( direct waves & reflect$ waves1 ! consequ5ce ( :i* be+ t po9ts 9 close proximity might be caus$ to move 9 opposite directions4 ,reflections su* z ^! w\ld be mo/ likely to occur ne> to ! junction ( /rata ( diff]5t ela/icity1 & x may be rem>k$ t x is (t5 ne> su* places t mu* twi/+ has be5 obs]v$4 ,ano!r way 9 :i* x is possible = twi/+ to h tak5 place w\ld be by ! int]f]5ce ( ! normal & transv]se waves :i* probably always exi/ 9 an e>?quake %ock1 or by ! meet+ ( ! p>ts ( ! normal wave itself1 "o hav+ travell$ 9 a direct l9e f ! orig91 :il/ ! o!r1 travell+ ?r\gh v>iable mat]ial1 has _h its direction *ang$4 ,mallet1 h[ev]1 has %[n t ! rotation may h be5 9 _m cases br\ght ab\t )\t ! supposition ( any actual twi/+ motion ( ! e>?--a simple backw>d & =w>d motion be+ q suffici5t4 ,if "o block ( /one re/s ^u ano!r1 & ! two are %ak5 backw>ds & =w>ds 9 a /raight l9e1 & if ! v]tical ?r\gh ! c5tre ( gravity ( ! upp] block does n co9cide ) ! po9t :]e !re is ! greate/ friction betwe5 ! blocks1 rotation mu/ take place4 ,if ! v]tical ?r\gh ! c5tre ( gravity falls on "o side ( ! c5tre ( friction1 ! rotation w\ld be 9 "o direction1 :il/1 if on ! o!r side1 ! rotation w\ld be 9 ! opposite direction4 ,al?\gh ! above explanation is simple1 & also 9 _m cases probably true1 x h>dly appe>s suffici5t to acc\nt = all ! ph5om5a :i* h be5 obs]v$4 ,?us1 = in/ance1 if ! /ones 9 ! ,yokohama cemet]y1 at ! "t ( ! e>?quake ( #ahhj1 _h be5 twi/$ 9 consequ5ce ( ! cause sugge/$ by ,mallet1 we %\ld mo/ c]ta9ly h f\nd t "s /ones _h turn$ 9 "o direction :il/ o!rs _h be5 twi/$ 9 ano!r4 ,by a c>eful exam9ation ( ! rotat$ /ones1 ,i f\nd t e /one--! /ones be+ 9 p>allel l9es--_h revolv$ 9 ! same direction1 namely 9 a direction opposite to t ( ! h&s ( a wat*4 ,z x w\ld seem highly improbable t ! c5tre ( greate/ friction 9 all ^! /ones ( diff]5t sizes & %apes %\ld h be5 at ! same side ( _! c5tres ( gravity1 an effect l ?is c\ld only be expla9$ by ! conjo9t action ( two successive %ocks1 ! direction ( "o be+ transv]se to ! o!r4 ,al?\gh fully recognis+ ! suffici5cy ( two transv]se %ocks to produce ! effects :i* h be5 obs]v$ 9 ,yokohama1 ,i w (f] :at appe>s to me to be ! true explanation ( ?is ph5om5on3 x 0 fir/ sugge/$ by my colleague1 ,mr4 ,gray1 & appe>s to be simpl] ?an any ) :i* ,i am acqua9t$4 ,illu/ration3 ,,fig4 #cj4 ,if any column>-l object1 = example a prism :i* ! basal section is repres5t$ by ,a ,b ,c ,d 7see fig4 #cj71 receives a %ock at "r angles to ,b ,c1 !re w be a t5d5cy = ! in]tia ( ! body to cause x to ov]turn on ! edge ,b ,c4 ,if ! %ock 7 at "r angles to ,d ,c1 ! t5d5cy w\ld be to ov]turn on ! edge ,d ,c4 ,if ! %ock 7 9 ! direction ( ! diagonal ,c ,a1 ! t5d5cy w\ld be to ov]turn on ! po9t ,c4 ,let u1 h[ev]1 n[ suppose ! impulse to be 9 "s direction l ,e ,g1 :]e ,g is ! c5tre ( gravity ( ! body4 ,= simplicity we may imag9e ! ov]turn+ effect to be an impulse giv5 ?r\gh ,g 9 an opposite direction--t is1 9 ! direction ,g ,e4 ,?is =ce w t5d to tip or make ! body be> heavily on ,c1 & at ! same "t to :irl r\nd ,c z an axis1 ! direction ( turn be+ 9 ! direction ( ! h&s ( a wat*4 ,if1 h[ev]1 ! direction ( impulse _h be5 ,e ,g1 !n1 al?\gh ! turn+ w\ld /ill h be5 r\nd ,c1 ! direction w\ld h be5 opposite to t ( ! h&s ( a wat*4 ,to put ^! /atem5ts 9 ano!r =m1 imag9e ,g ,e to be resolv$ into two compon5ts1 "o ( !m along ,g ,c & ! o!r at "r angles1 ,g ,f4 ,"h ! compon5t ( ! direction ,g ,c t5ds to make ! body tip on ,c1 :il/ ! o!r compon5t along ,g ,f causes revolution4 ,simil>ly ,g ,e may be resolv$ into its two compon5ts ,g ,c & ,g ,f1 ! latt] be+ ! "o t5d+ to cause revolution4 ,f ?is we see t if a body has a rectangul> section1 s long z x is act$ ^u by a %ock :i* is p>allel to its sides or to its diagonals1 !re ought n to be any revolution4 ,if we divide our section ,a ,b ,c ,d up into eight divisions by l9es ?r\gh ^! directions1 we %all see t any %ock ! direction ( :i* passes ?r\gh any ( ! octants :i* are %ad$ w cause a positive revolution 9 ! body--t is to say1 a revolution correspond+ 9 its direction to t ( ! movem5ts ( ! h&s ( a wat*2 :il/ if its direction passes ?r\gh any ( ! rema9+ octants ! revolution w be negative1 or opposite to t ( ! h&s ( a wat*4 ,f ! direction 9 :i* any giv5 /one has turn$1 we c !re=e give two sets ( limits betwe5 "o ( :i* ! %ock mu/ h come4 ,fur!r1 x w be obs]v$ t ! t5d5cy ( ! turn+ is to br+ a /one1 l ! "o we are discuss+1 broadside on to ! %ock2 !re=e1 if a /one ) a rectangul> cross section has turn$ suffici5tly1 ! direction ( a %ock w be p>allel to "o ( its faces1 b if x has n turn$ suffici5tly x w be m ne>ly p>allel to its faces 9 _! new position ?an x 0 to its faces :5 9 _! orig9al position4 ,if a /one receives a %ock ne>ly p>allel ) its diagonal1 on acc\nt ( its in/ability x may turn ei!r positively or negatively accord+ z ! friction on its base or "s irregul>ity ( surface be>+ mo/ influ5ce4 ,simil>ly1 if a /one receives a %ock p>allel to "o ( its faces1 ! twi/+ may be ei!r positive or negative1 b ! probability is t x w\ld only turn slightly2 :]eas 9 ! =m] case1 :]e ! %ock 0 ne>ly p>allel to a diagonal1 ! turn+ w\ld probably be great4 ,det]m9ation ( direction f in/rum5ts4--,:5 speak+ ab\t e>?quakes x 0 %[n1 z ! result ( _m obs]vations1 t ! same e>?quake 9 ! space ( a few seconds1 al?\gh x may sometimes h only "o direction ( motion1 v (t5 has _m directions ( motion4 ,9 c]ta9 cases1 !re=e1 our records1 if we assume ! mo/ p]man5t motions to be normal ones1 give def9ite & valuable results4 ,9 o!r cases x is necess>y to c>efully analyse ! records1 comp>+ ^? tak5 at "o /ation ) ^? tak5 at ano!r4 ,"o rem>kable fact :i* has be5 po9t$ out 9 ref]5ce to artificial e>?quakes produc$ by explod+ *>ges ( gunp[d] or dynamite1 & also ) reg>d to c]ta9 e>?quakes1 is t ! greate/ motion ( ! gr\nd is inw>ds1 t[>ds ! po9t f :i* ! di/urbance orig9at$4 ,%\ld ?is prove ! rule1 x gives a means ( det]m9+1 n only ! direction ( e>?quake1 b ! side f :i* x came4 ,det]m9ation ( e>?quake orig9s by "t obs]vations4--,! times at :i* an e>?quake 0 felt at a numb] ( /ations are among ! mo/ important obs]vations :i* c be made = ! det]m9ation ( an e>?quake orig94 ,! me?ods ( mak+ "t obs]vations1 & ! difficulties :i* h to be ov]come1 h already be5 describ$4 ,:5 det]m9+ ! direction f :i* a %ock has orig9at$1 or det]m9+ ! orig9 ( ! %ock by means ( "t obs]vations1 x has be5 usual to assume t ! velocity ( propagation ( ! %ock has be5 uni=m f ! orig94 ,! errors involv$ 9 ?is assumption appe> to z foll[s3-- #a4 ,we "k f obs]vations on artificial e>?quakes t ! velocity ( propagation is great] betwe5 /ations ne> to ! orig9 ( ! %ock ?an x is betwe5 m remote /ations2 & also ! velocity ( propagation v>ies ) ! initial =ce :i* produc$ ! di/urbance4 ,if our po9ts ( obs]vation are suffici5tly close toge!r z comp>$ ) _! di/ance f ! orig9 ( ! di/urbance1 x is probable t errors ( ?is description are small & w n make mat]ial diff]5ces 9 ! g5]al results4 #b4 ,we h reasons = believ+ t ! transit velocity ( an e>?quake is dep5d5t on ! nature ( ! rocks ?r\gh :i* x is propagat$4 ,errors :i* arise f causes ( ?is description w1 h[ev]1 be practically elim9at$ if our obs]vation po9ts are situat$ on an area suffici5tly l>ge1 s t ! di/ribution ( ! causes t5d+ to alt] ! velocity ( a %ock balance ea* o!r4 ,x mu/ be rem>k$1 t causes ( ?is description may also produce an alt]ation 9 ! direction ( our %ock4 ,o!r errors :i* may sometimes ent] into our results1 :5 det]m9+ ! orig9 ( %ocks by means ( obs]vations on velocities1 are ! assumptions t ! di/urbance has travell$ along ! surface f ! epic5trum & n 9 a direct l9e f ! c5trum4 ,aga91 x is assum$ t ! orig9 is a po9t1 :]eas x may possibly be a cavity or a fissure4 ,la/ly1 if we desire extreme accuracy1 we mu/ make due all[ance = ! sph]icity ( ! e>? & ! diff]5ces ( elevation ( ! obs]v+ /ations4 ,i4 ,! me?od ( /raight l9es4--,giv5 a numb] ( pairs ( po9ts ,a#j1 ,a#a1 ,b#j1 ,b#a1 ,c#j1 ,c#a1 c41 at ea* ( :i* ! %ock 0 felt simultane\sly1 to det]m9e ! orig94 ,!oretically if we bisect ! l9e :i* jo9s ,a#j & ,a#a by a l9e at "r angles to ,a#j1 ,a#a1 & simil>ly bisect ! l9es ,b#j1 ,b#a1 ,c#j1 ,c#a1 all ^! bisect+ l9es a#j1 a#a1 b#j1 b#a1 c#j1 c#a1 c41 ought to int]sect 9 a po9t1 :i* po9t w be ! epic5trum or ! po9t above ! orig94 ,?is me?od w fail1 fir/1 if ,a#j1 ,a#a1 ,b#j1 ,b#j1 ,c#j1 ,c#a =m a cont9u\s /raight l9e1 or if !y =m a s]ies ( p>allel l9es4 ,hopk9s gives a me?od bas$ on a pr9ciple simil> to ! "o :i* is "h employ$--namely1 giv5 t a %ock arrives simultane\sly at ?ree po9ts to det]m9e1 ! c5tre4 ,9 ?is case1 ! relative positions ( ! ?ree po9ts1 :]e ! "t ( arrival 0 simultane\s1 mu/ be accurately kn[n1 & ^! ?ree po9ts mu/ n lie 9 a /raight l9e1 or ! me?od w fail4 ,= practical application ! problem mu/ be re/rict$ to ! case ( ?ree po9ts :i* d n lie ne>ly 9 ! same /raight l9e4 ,,ii4 ,! me?od ( circles4--,giv5 ! times t#j1 t#a1 t#b1 c41 at :i* a %ock arriv$ at a numb] ( places ,a#j1 ,a#a1 ,a#b1 c41 to det]m9e ! position f :i* ! %ock orig9at$4 ,suppose ,a#j to be ! place :i* ! %ock rea*$ fir/1 & t x rea*$ ,a#a1 ,a#b1 ,a#c1 c41 successively aft]w>ds4 ,let t#a - t#j a t#b - t#j b t#c - t#j c1 c4 ,) ,a#a1 ,a#b1 ,a#c1 c4 z c5tres1 describe circles ) radii proportional to ! kn[n qualities a1 b1 c1 c41 & also a circle :i* passes ?r\gh ,a#j & t\*es ^! circles4 ,! c5tre ( ! la/ circle w be ! epic5trum4 ,! radii proportional to a1 b1 c1 c4 may be repres5t$ by ! quantities ax1 bx1 cx1 c41 :]e x is ! velocity ( propagation ( ! %ock4 ,x w be obs]v$ t ! times at :i* ! %ock arriv$ at ?ree places might alone be suffici5t4 ,if1 in/ead ( tak+ ! times ( arrival ( a %ock1 ! arrival ( a sea wave be tak51 ! result w\ld be a clos] approximate to ! absolute tru?4 ,x w be obs]v$ t ?is me?od is n a direct "o1 b is "o ( trial4 ,if1 h[ev]1 an imag9>y case be tak51 & ?ree giv5 po9ts ( obs]vation1 ,a#j1 ,a#a1 ,a#b1 be plott$ on a piece ( pap]1 x w be f\nd t x is n a difficult matt] to det]m9e two numb]s proportional to a & b :i* w all[ y to draw two circles s t !y may be t\*$ by a ?ird circle drawn ?r\gh ,a#j4 ,?is problem has practically be5 appli$ 9 ! case ( ! arrival ( a sea wave at a numb] ( places on ! ,s\? ,am]ican coa/1 at ! "t ( ! e>?quake ( ,may #i1 #ahgg4 ,?is is illu/rat$ z foll[s4 ,! places :i* 7 *os5 7 ,huanillos1 ,tocopilla1 ,cobija1 ,iquique1 ,mejillones4 ,9 ! foll[+ table ! fir/ column gives ! times at :i* ! sea wave arriv$ at ea* ( ^! places 9 ,iquique "t2 9 ! second column ! diff]5ce betwe5 ^! times & ! "t at :i* x rea*$ ,huanillos is giv52 9 ! ?ird column ! di/ances ?r\gh :i* a sea wave1 propagat$ at ! rate ( #cej feet p] second1 c\ld travel dur+ ! int]vals not$ 9 ! second column is giv54 ---------------------------------------- ---- ,arrival ,"t aft] ,di/ance at ( sea arrival at#cej feet p] wave ,huanillos second ---------------------------------------- ---- h4 m4 m9utes miles ,huanillos #h #cj #j #j ,tocopilla #h #cb #b #h ,cobija #h #ch #h #cb ,iquique #h #dj #aj #dj ,mejillones #h #df #af #fd ---------------------------------------- ---- ,! di/ances m>k$ 9 ! ?ird column are us$ z radii ( ! circles drawn r\nd ! places to :i* !y respectively ref]4 ,! c5tre ( ! circle drawn to t\* ! circles ( ! fir/ column1 & at ! same "t to pass ?r\gh ,huanillos1 is m>k$ ,c4 ,! position f :i* ! %ock orig9at$ appe>s !re=e to h occurr$ v ne> to a place ly+ 9 ,long4 #g #ae ,w4 & ,lat4 #ba #bb ,s4 ,illu/ration3 ,,fig4 #ca4 ,! actual op]ations :i* 7 gone ?r\gh 9 mak+ ! accompany+ map 7 z foll[s4 ,fir/1 ! places ) :i* we _h to deal 7 repres5t$ on a map 9 or?ographical projection1 ! c5tre ( projection be+ ne> to ! c5tre ( ! map4 ,?is 0 done s t ! measurem5ts :i* 7 made ^u ! map might be m correct ?an ^? we %\ld obta9 f an ord9>y *>t :]e ?is portion ( ! _w 0 n ! c5tre ( projection4 ,next1 a numb] 0 tak5 z equal to ! velocity ) :i* ! sea wave _h travell$4 ,! fir/ velocity tak5 0 ab\t #djj feet p] second--?is be+ ab\t ! velocity ) :i*1 !oretically1 x mu/ h travell$ 9 an ocean hav+ a dep? equal to t indicat$ ^u ! *>ts--also x seem$ to h travell$ at ?is rate f ! v>i\s times ( arrival z record$ at places along ! coa/4 ,circles 7 !n drawn r\nd ,tocopilla1 ,cobija1 ,iquique1 & ,mejillones ) radii equal to #b1 #h1 #aj1 & #ae1 ea* multipli$ by 7#fj #djj74 ,x 0 !n se5 by trial t x 0 impossible to draw a s+le circle :i* %\ld t\* f\r circles & also pass ?r\gh ,huanillos4 ,^! f\r circles 71 9 fact1 too l>ge4 ,f\r new b small] circles1 :i* are %[n 9 ! map1 7 next drawn1 _! radii be+ respectively equal to ! numb]s #b1 #h1 #aj1 & #af1 ea* multipli$ by 7#fj #cej71 & x 0 f\nd t a circle1 ) a c5tre ,c1 c\ld be drawn :i* w\ld practically t\* ! f\r circles1 & at ! same "t w\ld pass ?r\gh ,huanillos4 ,,iii4 ,! me?od ( hyp]bolas4--,! me?od :i* ,i call t ( hyp]bolas is only ano!r =m ( ! me?od ( circles4 ,x is1 h[ev]1 useful 9 special cases1 z1 = in/ance1 :]e we h ! times ( arrival ( e>?quakes at only two /ations4 ,betwe5 ,tokio & ,yokohama1 at :i* places ,i frequ5tly obta9 tol]ably accurate "t records1 ! me?od has be5 appli$ on sev]al occasions ) advantage4 ,9 ! prec$+ example let u suppose t ! only "t records :i* we _h 7 = ,huanillos & ,mejillones1 & t ! wave 0 felt at ! latt] place sixte5 m9utes or #ifj seconds aft] x 0 exp]i5c$ at ! =m]4 ,call+ ^! places ,h & ,m respectively1 r\nd ,m draw a circle equal to ! #ifj multipli$ by ! velocity ) :i* ! wave 0 propagat$4 ,x is !n evid5t t ! orig9 ( ?is di/urbance mu/ be ! c5tre ( a circle :i* passes ?r\gh ,h & t\*es ! circle drawn r\nd ,m4 ,jo9 ,h ,m1 cutt+ ! circle r\nd ,m 9 ,y4 ,bisect ,y ,h 9 ,v4 ,x is evid5t t ,v is "o possible orig9 = ! di/urbance4 ,next1 f ,m1 9 ! direction ( ,h1 draw any l9e ,m ,z ,p2 jo9 ,z ,h2 bisect ,z ,h at "r angles by ! l9e ,o ,p ,n4 ,because ,,ph ,,pz1 x is evid5t t ,p is a second possible orig94 ,proce$+ 9 ?is way a s]ies ( po9ts ly+ to ! "r & left ( ,v on ! curve ,r ,v ,t may be f\nd1 & we may !re=e say t ! orig9 lies some:]e 9 ! curve ,r ,v ,t4 ,by increas+ or decreas+ our velocity we v>y ! position ( ! curve ,r ,v ,t1 &1 in/ead ( a l9e on :i* our orig9 may be1 we obta9 a b&4 ,z ! assum$ velocity increases1 ! circle r\nd ,m becomes l>g]1 & has its limit :5 x passes ?r\gh ,h1 :]e ! two arms ( ! curve ,r ,v ,t w close toge!r & =m a prolongation ( ! l9e ,m ,y ,h z ! assum$ velocity dim9i%es4 ,! circle r\nd ,m becomes small] until x co9cides ) ! po9t ,m4 ,at su* a mom5t ! curve ,r ,v ,t op5s out to =m a /raight l9e bisect+ ,m ,h at "r angles4 ,! curve ,r ,v ,t is a hyp]bola ) a v]tex ,v & foci ,h & ,m4 ,inasmu* z ,,pm - ,,ph a con/ant quantity4 ,if we h ! "t giv5 at :i* ! %ock or wave arriv$ at a ?ird /ation z at ,iquique1 x is evid5t t a second hyp]bola ,r ,v ,t might be drawn ) ,iquique & ,huanillos z foci1 & t ! mutual int]section ( ^! two hyp]bolas ) a ?ird hyp]bola1 hav+ = its foci ,iquique & ,mejillones1 w\ld give ! orig9 ( ! wave4 ,! obta9+ ( a mutual int]section w\ld dep5d on ! assum$ velocity1 & ! accuracy ( ! result1 l t ( ! me?od ( circles1 w\ld dep5d ^u ! trials we made4 ,! me?od "h enunciat$ may be c>ri$ f>!r by describ+ hyp]boloids in/ead ( hyp]bolas1 ! mutual int]section ( :i* surfaces w\ld1 9 ! case ( an e>? wave1 give ! actual orig9 or c5trum r ?an ! po9t above ! orig9 or epic5trum4 ,,iv4 ,! me?od ( co-ord9ates4--,giv5 ! times at :i* a %ock arriv$ at five or m places1 ! position ( :i* we h m>k$ ^u a map1 or *>t1 to det]m9e ! position on ! map ( ! c5tre ( ! %ock1 its dep?1 & ! velocity ( propagation4 ,comm5c+ ) ! place :i* 0 la/ rea*$ by ! %ock1 call ^! places p1 p#a1 p#b1 p#c1 & p#d1 & let ! times tak5 to rea* ^! places f ! orig9 be respectively t1 t#a1 t#b1 t#c1 & t#d4 ,?r\gh p draw rectangul> co-ord9ates1 & ) a scale measure ! co-ord9ates ( p#a1 p#b1 p#c1 & p#d1 & let ^! respectively be a#a1 b#a2 a#b1 b#b2 a#c1 b#c2 a#d1 b#d4 ,!n if x1 y1 & z be ! co-ord9ates ( ! orig9 ( ! %ock1 d1 d#a1 d#b1 d#c1 & d#d1 ! respective di/ances ( p1 p#a1 p#b1 p#c1 & p#d f ?is orig91 & v ! velocity ( ! %ock1 we h #a4 x#b y#b z#b d#b v#b t#b #b4 7a#a - x7#b 7b#a - y7#b z#b v#b t#ab #c4 7a#b - x7#b 7b#b - y7#b z#b v#b t#bb #d4 7a#c - x7#b 7b#c - y7#b z#b v#b t#cb #e4 7a#d - x7#b 7b#d - y7#b z#b v#b t#db ,because we "k ! actual times at :i* ! waves arriv$ at ! places p1 p#a1 p#b1 p#c1 p#d1 we "k ! values t--t#a1 t--t#b1 t--t#c1 t--t#d4 ,call ^! respectively m1 p1 q1 & r4 ,suppose t kn[n1 !n t#a t - m t#b t - p t#c t - q t#d t - r4 ,subtract+ equation ,no4 #a f ea* ( ! equations #b1 #c1 #d1 & #e1 we obta91 a#ab b#ab - #b;a#a x - #b;b#a y v#b 7t#ab - t#b7 v#b 7m#b - #bt m7 a#bb b#bb - #b;a#b x - #b;b#b y v#b 7t#bb - t#b7 v#b 7p#b - #bt p7 a#cc b#cb - #b;a#c x - #b;b#c y v#b 7t#cb - t#b7 v#b 7q#b - #bt q7 a#db b#db - #b;a#d x - #b;b#d y v#b 7t#db - t#b7 v#b 7r#b - #bt r7 ,n[ let v#b u1 & #bv#b t w4 ,!n #a4 #b;a#a x #b;b#a y u m#b - n m a#ab b#ab #b4 #b;a#b x #b;b#b y u p#b - n p a#bb b#bb #c4 #b;a#c x #b;b#c y u q#b - n q a#cb b#cb #d4 #b;a#d x #b;b#d y u r#b - n r a#db b#db ,we h "h f\r simple equations conta9+ ! f\r unkn[n quantities x1 y1 u1 & w4 x & y det]m9e ! orig9 ( ! %ock4 ,! absolute velocity v equals u4 ,f v & w we obta9 t4 ,sub/itut+ x1 y1 v1 & t 9 ! fir/ equation we obta9 z4 ,we h "h assum$ t ! po9ts ( obs]vation h all ab\t ! same elevation above sea level4 ,if x is ?\ght necess>y to take ^! elevations into acc\nt1 a six? equation may be introduc$4 ,if ! propagation ( ! wave is consid]$ z a horizontal "o1 z w\ld be done :5 calculat+ ! position ( ! epic5trum or po9t above ! orig91 by means ( ! times ( arrival ( a sea wave1 ! ord9ate z ( ! fir/ five equations w\ld be omitt$4 ,work+ 9 ?is way ! result+ f\r equations1 viz4 #b;a#a x #b;b#a y um#b - wm#b a#ab b#ab c4 c4 c4 rema9$ un*ang$4 ,apply+ ?is me?od to ! same example z t us$ z illu/ration = ! two previ\s me?ods1 we obta9 = ! co-ord9ates ( ,mejillones1 ,iquique1 ,cobija1 ,tocopilla1 & ,huanillos1 measur$ 9 geographical miles1 & ! times 9 ,iquique "t at :i* ! wave rea*$ ea*1 z giv5 9 ! foll[+ table2 ox & oy be+1 drawn ?r\gh ,mejillones4 ---------------------------------------- ------------------- ,co-ord9ates ,"t ( arrival ---------------------------------------- ------------------ ,,ox ,,oy h4 m4 ,mejillones a or #j b or #j #h #df p4 m4 ,iquique a#a or #aej b#a or #if #h #dj ,cobija a#b or #cf b#b or #ad #h #ch ,tocopilla a#c or #ff b#c or #ca #h #cb ,huanillos a#d or #ajb b#d or #eh #h #cj ---------------------------------------- ------------------ ,f ?is data we f9d ! co-ord9ates x & y ( ?is orig9 to be #heh & #efg2 :il/ ! velocity ( propagation #de feet p] second4 ,measur+ ^! ord9ates ^u ! map1 we obta9 a c5tre ly+ v ne> ,long4 #ga #e ,w4 & ,lat4 #ba #bb ,s41 a position :i* is v ne> to t :i* has already be5 obta9$ by o!r me?ods4 ,if in/ead ( ,huanillos we sub/itute ! ord9ates & "t ( arrival ( ! sea wave = ,pabalon de ,pica1 ano!r po9t = ! orig9 w be obta9$ ly+ f>!r out at sea4 ,to obta9 ! be/ result1 ! me?od to be tak5 w evid5tly be1 fir/ to reject ^? places at :i* x seems likely t "s mi/ake has be5 made ) ! "t obs]vations1 & !n ) ! rema9+ places to =m z _m equations z possible1 & f ^! to obta9 a mean value4 ,?is is a long & t$i\s process1 & z ! "t obs]vations ( ?is p>ticul> e>?quake are probably "o & all m or less inaccurate1 x is h>dly wor? :ile to foll[ ! inve/igation f>!r4 ,9 ?is example1 z 9 ! prec$+ ones1 x w be obs]v$ t x has be5 sea waves t h be5 dealt )1 r ?an e>? vibrations4 ,x is evid5t1 h[ev]1 t ^! latt] vibrations may be dealt ) 9 a simil> mann]4 ,9 ^! det]m9ations x w also h be5 obs]v$ t x is assum$ t ! di/urbance has radiat$ f a c5tre1 &1 !re=e1 approa*$ ! v>i\s /ations 9 diff]5t directions4 ,if we assume t we h ?ree /ations v ne> to ea* o!r z comp>$ ) _! di/ances f ! orig91 s t we c assume t ! wave fronts at ! v>i\s /ations 7 p>allel1 ! det]m9ation ( ! direction 9 :i* ! wave advanc$ appe>s to be mu* simplifi$4 ,! det]m9ation ( ! direction 9 :i* a wave has pass$ across ?ree /ations 0 fir/ giv5 by ,pr(essor ,haughton4 ,haughton's me?od4--,giv51 ! "t ( an e>?quake %ock at ?ree places1 to det]m9e its horizontal velocity & coseismal l9e4 ,! solution ( ?is is conta9$ 9 ! =mula a 7t#b - t#a7 s9 tan ---------------------------------------- ---------------------------------------- ----------------------------4 c 7t#c - t#b7 a 7t#b - t#a cos ,:5 ,a1 ,b1 & ,c are ?ree /ations at :i* a %ock is obs]v$ at ! times t#a1 t#b1 & t#c2 a1 b1 & c are ! di/ances betwe5 ,a1 ,b1 & ,c1 & is ! angle made by ! coseismal l9es x ,a x1 y ,b y1 & ! l9e ,a ,b1 :i* are assum$ to be p>allel4 ,?is ,i appli$ 9 ! case ( ! ,iquique e>?quake1 b ow+ to ! smallness ( ! angles betwe5 ! ?ree /ations ,a1 ,b1 & ,c1 ! result 0 unsatisfactory4 ,! problem ought to be re/rict$1 fir/1 to places :i* are a long di/ance away f a c5tre1 &1 secondly1 to places :i* are n ne>ly 9 a /raight l9e4 ,?is problem may be solv$ m readily by geometrical me?ods4 ,plot ! ?ree /ations ,a1 ,b1 & ,c on a map1 jo9 ! two /ations betwe5 :i* !re 0 ! greate/ diff]5ce 9 ! "t obs]vation4 ,let ^!1 = example1 be ,a & ,c4 ,divide ! l9e ,a ,c at po9t ,d1 s t ,a ,d 3 ,d ,c z ! int]val betwe5 ! %ock felt at ,a & ,b is to ! int]val betwe5 ! %ock felt at ,b & ,c4 ,! l9e ,b ,d w be p>allel to ! direction 9 :i* ! wave advanc$4 ,! diff]5ce 9 "t ( ! arrival ( two di/urbances4--,9 ! v>i\s calculations :i* h be5 made to det]m9e an orig9 bas$ on ! assumption ( a kn[n or ( a con/ant velocity1 we h only dealt ) a s+le wave1 :i* may h be5 a di/urbance 9 ! e>? or 9 ! wat]4 ,a factor :i* has n yet be5 employ$ 9 ?is inve/igation is ! diff]5ce 9 "t betwe5 ! arrival ( two di/urbances2 "o propagat$1 = in/ance1 ?r\gh ! e>?1 & ! o!r1 = example1 ?r\gh ! ocean4 ,! diff]5ce 9 ! times ( ! arrival ( two waves ( ?is description is a quantity :i* is s (t5 record$ t x is well n to pass x by unnotic$4 ,to ! waves m5tion$ we might also add s\nd waves1 :i* s frequ5tly accompany de/ructive e>?quakes1 &1 9 "s localities1 z1 = in/ance1 9 ,kamei%i1 9 ,nor? ,japan1 are also commonly associat$ ) e>?quakes ( b small int5sity4 ,x 0 by obs]v+ ! diff]5ce 9 "t betwe5 ! %ak+ & ! s\nd 9 diff]5t localities t ,signor ,abella 0 enabl$ to come to def9ite conclusions reg>d+ ! orig9 ( ! di/urbances :i* affect$ ! prov9ce ( ,neuva ,viscoya 9 ! ,philipp9es1 9 #ahha2 ! places :]e ! int]val ( "t 0 %ort1 or ! places :]e ! two ph5om5a 7 almo/ simultane\s1 be+1 9 all probability1 ne>] to ! orig9 ?an :5 ! int]vals 7 comp>atively l>ge4 ,i myself appli$ ! me?od ) consid]able success :5 seek+ = ! orig9 ( ! ,iquique e>?quake ( #ahgg4 ,! assumptions made 9 t p>ticul> in/ance 71 fir/1 t ! velocity ( ! di/urbance ?r\gh ! e>? 0 kn[n1 &1 secondly1 t ! velocity ) :i* a sea wave 0 propagat$ 0 also kn[n4 ,a me?od simil> to ! above 0 fir/ sugge/$ by ,hopk9s4 ,x dep5d$ on ! diff]5ces ( velocity ) :i* normal & transv]sal waves are propagat$4#he ,seeba*'s me?od4--,to det]m9e ! true velocity ( an e>?quake1 ! "t ( ! fir/ %ock1 & ! dep? ( ! c5tre4 ,illu/ration3 ,,fig4 #cb4 ,let ! /raight l9e ,m1 m#a1 m#b1 m#c repres5t ! surface ( ! e>? %ak5 by an e>?quake4 ,= small e>?quakes1 to consid] ! surface ( ! e>? z a plane w n lead to s]i\s errors4 ,if an e>?quake orig9ates at ,c1 !n to rea* ! surface at ,m x trav]ses a di/ance h 9 ! "t t4 ,to rea* ! surface at ,m#a x trav]ses a di/ance h x#a 9 a "t t#b4 ,if v equals ! velocity ( propagation1 h h x#a !n t ------1 t#a --------------------------1 v v h x#b t#b --------------------------1 c4 v ,seeba* n[ says t if we h giv5 ! position ( ,m or epic5trum ( ! %ock1 & draw ?r\gh x rectangul> axes l ,m m#c & ,m ,t#c1 & lay d[n on ,m m#c 9 miles ! di/ances f ,m ( ! v>i\s /ations :i* h be5 %ak51 & 9 equal divisions = m9utes lay d[n on ,m ,t#c ! diff]5ces ( "t at :i* ,m1 m#a1 m#b1 c4 7 %ak51 !n ,m#a ,t#a1 ,m#b ,t#b1 c4 are ! co-ord9ates ( po9ts on an hyp]bola4 ,! degree ( exactness ) :i* ?is hyp]bola is 9 any giv5 case con/ruct$ is a *eck ^u ! accuracy ( ! "t obs]vations & ! position ( ! epic5trum4 ,! apex ( ! hyp]bola is ! epic5trum4 ,! int]section ( ! asymptote ) ! ord9ate axis is ! "t po9t ( ! fir/ %ock1 :i*1 because ! scale = "t & = space 7 tak5 z equal1 gives ! absolute position ( ! c5trum4 ,?is int]section is %[n by dott$ l9es4 ,kn[+ ! position ( ! c5trum1 we c directly read f our diagram h[ f> ! di/urbance has be5 propagat$ 9 a giv5 "t4 ,,*apt] ,,xi4 ,,! ,,dep? ,,( ,,an ,,e>?quake ,,c5trum4 ,! dep? ( an e>?quake c5trum--,greate/ possible dep? ( an e>?quake--,=m ( ! focal cavity4 ,dep? ( c5trum4--,! fir/ calculations ( ! dep? at :i* an e>?quake orig9at$ 7 ^? made by ,mallet = ! ,neapolitan e>?quake ( #aheg4 ,^! 7 made on ! assumption t ! e>? wave radiat$ 9 /raight l9es f ! orig91 &1 !re=e1 at po9ts at diff]5t di/ances f ! epic5trum x _h diff]5t angles ( em]g5ce4 ,^! angles ( em]g5ce 7 *iefly calculat$ f ! incl9ation ( fissures produc$ 9 c]ta9 build+s1 :i* 7 assum$ to be at "r angles to ! direction ( ! normal motion4 ,if we h det]m9$ ! epic5trum ( an e>?quake & ! muzoseismal circle1 & make ei!r ! assumption t ! angle ( em]g5ce 9 ?is circle has be5 #de or #ed #dd #i 7see page #ed71 x is evid5tly an easy matt] by geometrical con/ruction to det]m9e ! dep? ( ! c5trum4 ,hf] foll[$ ?is me?od :5 inve/igat+ ! e>?quake ( ,belluno4 ,o!r me?ods ( calculation :i* h be5 employ$ are bas$ on "t obs]vations1 z1 = in/ance1 ! me?od ( ,seeba*1 ! me?od ( co-ord9ates1 ! me?od ( hyp]boloids or sph]es 7see pages #bjj-bab74 ,by means ( a numb] ( l9es p>allel to tw5ty-six angles ( em]g5ce1 drawn 9 t[>ds ! seismic v]tical1 ,mallet f\nd t tw5ty-?ree ( ^! int]sect$ at a dep? ( #g geographical miles4 ,! maximum dep? 0 #h geographical miles1 & ! m9imum dep? #b geographical miles4 ,! mean dep? 0 tak5 at a dep? ( #e geographical miles :]e1 )9 a range ( #ab1jjj feet1 eighte5 ( ! wave pa?s int]sect$ ! seismic v]tical4 ,! po9t :]e ^! wave pa?s />t ?icke/ is at a dep? n great] ?an ?ree geographical miles1 & ?is is consid]$ to be ! v]tical dep? ( ! focal cavity itself4 ,= ! ,yokohama e>?quake ( #ahhj1 f ! indications ( seismomet]s1 & by o!r means1 c]ta9 angles ( em]g5ce 7 obta9$1 lead+ to ! conclusion t ! dep? ( orig9 ( t e>?quake might be betwe5 #a & #e miles4 ,possibly1 p]haps1 ! e>?quake may h orig9at$ f a fissure ! v]tical dim5sions ( :i* 0 compris$ betwe5 ^! dep?s4 ,a s\rce ( error 9 a calculation ( ?is description is t ! v]tical motions may h be5 a compon5t ( transv]se motions or p]haps due to ! slope ( surface waves4 ,! foll[+ table ( ! dep?s at :i* c]ta9 e>?quakes h orig9at$ has be5 compil$ f ! writ+s ( sev]al obs]v]s4 ---------------------------------------- ---------------------- ,9 feet ---------------------------------------- ------------------- ,m9imum ,mean ,maximum ,rh9el& #ahdf 7,s*midt7 #abg1cji ,silli5 #aheh 7,s*midt7 #hf1agc ,middle ,g]many #ahgb 7,seeba*7 #dg1bbe #eh1iab #gj1hda ,h]zog5ra? #ahgc 7,lasaulx7 #af1eec #cf1eaf #ef1dgg ,neapolitan #aheg 7,mallet7 #af1gje #cd1icj #di1cei ,yokohama #ahhj 7,milne7 #g1ibj #ag1bfj #bf1djj ---------------------------------------- ------------------- ,a table simil> to ?is has be5 compil$ by ,lasaulx4#hf ,) ! exception ( ! det]m9ation = ! two la/ di/urbances ^! calculations h be5 made ) ! assi/ance ( ! me?od ( ,seeba*1 :i* dep5ds1 among/ o!r ?+s1 on ! assumptions ( exact "t det]m9ations1 direct transmission ( waves f ! c5trum1 & a con/ant velocity ( propagation4 ,admitt+ t our obs]vations ( "t are practically accurate1 x appe>s t ! o!r assumptions may (t5 lead to errors ( su* magnitude t our results may be ( b little value4 ,f :at has be5 said respect+ ! velocity ) :i* e>? di/urbances are propagat$1 x seems t ^! velocities may v>y betwe5 l>ge limits1 be+ greate/ ne>e/ to ! orig94 ,if we ref] to ,seeba*'s me?od1 we %all see t a condition ( ?is k9d w\ld t5d to make ! diff]5ces 9 "t betwe5 v>i\s places1 z we rec$e f ! epic5trum1 great] ?an t requir$ = ! con/ruction ( ! hyp]bola4 ,! curve :i* is obta9$ w\ld1 9 consequ5ce1 h bran*es /eep] ?an t ( ! hyp]bola1 & ! resultant dep?1 obta9$ by ! int]section ( ! asymptotes ( ?is curve ) ! seismic v]tical1 indicates an orig9 :i* may be mu* too great4 ,ano!r po9t wor?y ( att5tion1 :i* is common to ! me?od ( ,mallet z well z to t ( ,seeba*1 is ! "q :e!r ! %ock radiates directly f ! orig91 or is propagat$ f ! orig9 m or less v]tically to ! surface1 & !n spreads horizontally4 ,we "k t e>?quakes1 bo? natural & artificial1 may be propagat$ z undulations on ! surface ( ! gr\nd1 & t ! v]tical motion ( ! latt]1 z te/ifi$ by ! records ( well-con/ruct$ in/rum5ts1 has no practical connection ) ! dep? f :i* ! di/urbance orig9at$4 ,9 cases l ^!1 ! direction ( cracks 9 build+s1 & o!r ph5om5a usually accr$it$ to a normal radiation1 may 9 reality be due to *anges 9 incl9ation ( ! surface on :i* ! di/urb$ objects re/$4 ,:5 our po9ts ( obs]vation are at a di/ance f ! epic5trum ( ! di/urbance :i*1 z comp>$ ) ! dep? ( ! same1 is n great1 calculations or obs]vations bas$ on ! assumption ( a direct radiation ( ! di/urbance may possibly lead to results :i* are tol]ably correct4 ,! calculations ( ,mallet = ! ,neapolitan e>?quake appe> to h be5 made "u su* conditions4 ,= small] e>?quakes1 & = places at a di/ance f ! seismic v]tical ( a de/ructive e>?quake1 ! results :i* are d$uc$ f ! obs]vations on %att]$ build+s1 & all obs]vations bas$ ^u ! assumption ( direct radiation1 we mu/ accept ) caution4 ,ano!r error :i* may ent] into calculations ( ?is description is "o :i* has be5 discuss$ by ,mallet at "s l5g?4 ,?is is ! effect :i* ! =m & ! position ( ! focal cavity may h ^u ! transmission ( waves4 ,%\ld ! impulse orig9ate f a po9t or sph]ical cavity1 !n we might1 9 a homog5e\s m$ium p]haps1 reg>d ! isoseismals z conc5tric circles1 & expect to f9d t equal effects _h be5 produc$ at equal di/ances f ! epic5trum4 ,%\ld1 h[ev]1 ?is cavity be a fissure1 x is evid5t t ev5 9 a homog5e\s m$ium ! incl9ation ( ! plane ( su* a cavity w h consid]able effect ^u ! =m ( ! waves :i* w\ld radiate f its two walls4 ,= example1 let x be assum$ t ! fir/ impulse ( an e>?quake is due to ! sudd5 =mation ( a fissure1 r5t op5 f its c5tre1 & t ! waves leave ! walls at all po9ts normal to its surface4 ,!n1 z ,mallet po9ts out1 x is evid5t t ! di/urbance w spread out 9 ellipsoidal waves1 ! greate/ axis ( :i* w be p]p5dicul> to ! plane ( ! fissure4 ,by tak+ a numb] ( cases ( fissures ly+ 9 v>i\s directions & draw+ ! ellipsoidal waves :i* w\ld result f an ela/ic pressure1 l t ( /eam sudd5ly admitt$ into su* cavities1 ! diff]5ces 9 effect :i* w\ld be simultane\sly produc$ by ^! waves on rea*+ ! surface c be readily und]/ood4 ,! foll[+ example ( an inve/igation on ?is subject w s]ve z an example to illu/rate ! g5]al nature ( ! _m o!r cases :i* might be tak54 ,illu/ration3 ,,fig4 #cc4 ,let a di/urbance simultane\sly orig9ate f all po9ts ( ! fissure f f4 ,?is w spread outw>ds 9 ellipsoidal %ells to ! surface ( ! e>? e e4 ,! major axis ( ^! ellipsoidal %ells w be ! direction ( greate/ effect4 ,9 ! direction c d ! waves w plunge into ! e>?1 & places to ! "r side ( ! fissure w1 to use an expression due to ,/okes1 :5 speak+ ( analog\s ph5om5a connect$ ) s\nd1 be 9 e>?quake %ad[4 ,! same expression has be5 employ$1 some:at diff]5tly1 :5 speak+ ( ! effects produc$ on build+s4 ,= places1 l s & p1 situat$ at equal di/ances f ! seismic v]tical1 x is evid5t t ! int5sity ( ! %ock w be diff]5t1 & also its "t ( arrival4 ,x w also be obs]v$ t ! isoseismals w take ! =m ( ovals or di/ort$ ellipses1 ! l>g] or full] end ( :i* be+ to ! left ( ! fissure4 ,o!r cases1 l ^? j giv51 :i* are discuss$ by ,mallet 9 8 acc\nt ( ! ,neapolitan e>?quake1 are :]e ! fissure =ms ! division betwe5 mat]ials ( diff]5t ela/icities4 ,9 ! h>d & m ela/ic mat]ial ! waves w be m cr[d$1 ! velocity ( a wave p>ticle w be great]1 & ! transit w be quick] ?an 9 ! less ela/ic m$ium4 ,! result is t ! di/ance ( equal effect f ! seismic v]tical w be greate/ 9 ! direction ( ! m compressible mat]ial4 ,unless ^! consid]ations are kept c>efully be=e ! m9d :5 inve/igat+ ! dep? &1 we may add1 ! position & =m ( ! c5trum ( an e>?quake1 s]i\s errors may arise4 ,greate/ dep? ( an e>?quake orig94--,a curi\s b in/ructive calculation :i* ,mallet made 0 a det]m9ation ( ! greate/ possible dep? at :i* an e>?quake may occur4 ,?is calculation is bas$ ^u ! idea t ! impulsive effect ( an e>?quake has an intimate relation%ip ) ! height ( neighb\r+ volcanoes1 ! column ( lava support$ on a volcanic cone be+ a measure ( ! int]nal pressure t5d+ to rupture ! adjac5t cru/ ( ! e>?4 ,mit*ell1 9 #agjj1 virtually prop\nd$ ?is idea1 :5 he sugge/$ t ! velocity ( propagation ( an e>?quake 0 relat$ to ! height ( su* a column4#hg ,mallet %[$ t !re 0 probably consid]able tru? 9 su* a supposition by appeal+ to ! results ( actual obs]vation4 ,! pressure gauge ( ! ,neapolitan di/rict w\ld be ,vesuvius1 ! height ( :i* has 9 r\nd numb]s v>i$ betwe5 #c1ejj to #d1jjj feet4 ,"o ( ! mo/ de/ructive e>?quakes 9 ?is di/rict--namely1 ! "o ( #aheg--project$ bodies ) an initial velocity ( ab\t fifte5 feet p] second4 ,! ,riobamba e>?quake1 :i* project$ bodies ) an initial velocity ( eighty feet p] second1 appe>s to h be5 ! mo/ viol5t e>?quake1 s f> z its impulsive ef=t is conc]n$1 ( :i* we h any record4 ,x occurr$ among/ ! ,&es1 :]e !re are volcanoes f #af1jjj to #ba1jjj feet 9 height4 ,comp>+ ^! two e>?quakes toge!r1 we see t ! ,riobamba %ock _h a de/ructive p[] #ecc times t ( ! ,neapolitan %ock1 & we also see t ! ,riobamba volcanoes 7 ab\t #ecc times high] ?an ,vesuvius4 ,! accordance 9 ^! quantities is c]ta9ly int]e/+1 & t5ds to sub/antiate ! idea t volcanoes are b>ometrical-l pressure gauges ( a di/rict4 ,c>ry+ ! argum5t /ill fur!r4 ,mallet says t if ! dep? ( orig9 ( e>?quakes 7 ! same1 !n ! area ( di/urbance w\ld1 = l =mations & configuration ( surface1 be a measure ( ! e>?quake ef=t1 & also "s function ( ! velocity ( ! wave4 ,f ?is we may g5]ally inf] #8t e>?quakes1 l t ( ,lisbon1 :i* h a v great area ( s5sible di/urbance1 h also a v deep seismal focus1 & also ! greate/ dep? ( seismal focus )9 our planet is probably n great] ?an t asc]ta9$ = ?is ,neapolitan e>?quake1 multipli$ by ! ratio t ! velocity ( ! ,riobamba wave be>s to t ( its wave1 or1 :at is ! same ?+1 by ! ratio ( ! altitudes ( ! volcanoes ( ! ,&es to t ( ,vesuvius4' ,n[1 z ! dep? ( ! ,neapolitan %ock may be tak5 at #cd1icj feet1 ! greate/ probable dep? ( orig9 ( any e>?quake impulse occurr+ 9 our planet is limit$ to #eccc #d1icj feet1 or #cjfd geographical miles4 ,+5i\s z ?is argum5t is1 we c h>dly admit x )\t c]ta9 qualifications4 ,fir/1 we are call$ ^u to admit ! id5tity ( ! orig9at+ cause ( ! volcano & ! e>?quake--z to :at may be ! orig9at+ cause ( e>?quakes we h yet to ref]1 b c]ta9ly 9 ! case ( p>ticul> e>?quakes1 z1 = in/ance1 ^? :i* occur 9 c\ntries l ,scotl&1 ,sc&9avia1 & portions ( ,sib]ia1 ! direct connection betwe5 ^! ph5om5a are n at fir/ sight v app>5t4 ,secondly1 ev5 if we admit ! id5tity ( ! orig9 ( ^! ph5om5a1 x is n difficult to imag9e t ! fluid pressure br\ght to be> ^u c]ta9 portions ( ! cru/ ( ! e>? may possibly 9 _m in/ances be inf9itely great] ?an t indicat$ by ! height ( ! column ( liquid lava 9 ! ?roat ( a volcano1 ! true height ( :i* we are unable to obta94 ,fur!r1 9 c]ta9 in/ances su* a column only appe>s to be a measure ( ! pressure ^u ! cru/ ( ! e>? 9 ! imm$iate vic9ity ( ! cone4 ,?us1 9 ! ,s&wi* ,isl&s1 we h lava /&+ 9 ! ?roat ( ! volcano ( ,mauna ,loa #aj1jjj feet high] ?an x /&s 9 ! crat] ,kilauea1 only tw5ty miles di/ant4 ,t ^! columns %\ld be measures ( ! same pressure1 orig9at+ 9 a g5]al subt]ranean liquid lay] ) :i* !y are connect$1 is a supposition difficult to satisfactorily sub/antiate4 ,ano!r measure ( ! impulsive ef=ts :i* subt]ranean =ces may ex]t ^u ! cru/ above !m is evid5tly ! height to :i* volcanoes eject mat]ials4 ,cotopaxi is said to h hurl$ a #bjj-ton block ( /one n9e miles4 ,sir ,w4 ,hamilton tells u t 9 #aggi ,vesuvius %ot up a column ( a%es #aj1jjj feet 9 height2 & ,judd tells u t ?is same m\nta9 9 #ahgb ?rew up vap\rs & rock fragm5ts to ! enorm\s height ( #bj1jjj feet4 ,?is w\ld indicate an initial velocity ( #a1aca feet p] second4 ,not)/&+ ,mallet's calculation t ?irty miles is ! limit+ dep? = ! orig9 ( an e>?quake1 ! orig9 ( ! ,ow5's ,valley e>?quake ( ,m>* #ahgb 0 e/imat$ z be+ at lea/ fifty miles4#hh ,=m ( ! focal cavity4--,among ! v>i\s problems :i* are put be=e ^? :o /udy ! physics ( ! int]ior ( our e>? x w\ld at fir/ sight appe> t !re 0 none m difficult ?an ! attempt to det]m9e ! =m ( ! cavity1 if x be a cavity1 f :i* an e>?quake orig9ates4 ,almo/ all inve/igators ( seismology h recognis$ t ! bir?place ( an e>?quake is n a po9t1 & h made sugge/ions ab\t its g5]al nature4 ,! ord9>y supposition is t ! e>?quake orig9ates f a fissure1 & if ! focus ( a di/urbance c\ld be laid b>e to u x w\ld h ! appe>ance ( a fault su* z we s (t5 see expos$ on ! faces ( cliffs4 ,a /rong argum5t1 t5d+ to demon/rate t "s ( ! %ak+s :i* are felt 9 ,japan are due to ! production ( su* fissures1 is ! fact t ! vibrations :i* are record$ are transv]se to a l9e jo9+ ! po9t ( obs]vation & ! di/rict f :i*1 by "t obs]vations1 we "k ! %ock to h orig9at$4 ,! mo/ probable explanation ( ?is ph5om5a appe>s to be t "o mass ( rock has be5 slid+ across ano!r mass1 giv+ rise to %e>+ /ra9s1 & produc+ waves ( di/ortion4 ,! fir/ seismologi/ :o attack$ ! problem ( f9d+ out ! dim5sions & position ( su* a fissure 0 ,mallet1 :5 work+ on ! ,neapolitan e>?quake ( #aheg4 ,! reasons t ! orig9 %\ld1 9 ! fir/ place1 h be5 a fissure1 r ?an any o!r =m ( cavity1 0 t su* a supposition seem$ to be a priori ! mo/ probable1 &1 fur!r1 t x af=d$ a bett] explanation ( ! v>i\s ph5om5a :i* 7 obs]v$1 ?an t obta9$ f any o!r assumption4 ,! me?od on :i* ,mallet work$ to det]m9e ! =m & position ( ! assum$ fissure1 :i* me?od 0 subsequ5tly m or less closely foll[$ by o!r inve/igators1 0 z foll[s3-- ,f an obs]vation ( ! v>i\s ph5om5a produc$ ^u ! surface ( ! di/urb$ area1 a map ( isoseismals 0 con/ruct$4 ,^! 7 se51 z has be5 ! case ) _m e>?quakes1 n to di/ribute !mselves 9 circles r\nd ! epic5trum1 b z di/ort$ oval or elliptical figures1 ! major axes ( :i* r\ghly co9cid$ ) ea* o!r4 ,fur!r1 ! epic5trum1 did n lie 9 ! c5tre ( ^! ovals1 b 0 ne> to ! n>r[ end :]e !y conv]g$4 ,?is at once %[$1 if ! reason+ respect+ ! mann] 9 :i* waves are propagat$ f an incl9$ fissure be correct1 t ! fissure 0 at "r angles to ! major axis ( ! curves1 dipp+ f _! n>r[ end d[nw>ds1 9 ! direction ( _! l>g] widespread ends4 ,! next weapon :i* ,mallet employ$ to attack ?is problem 0 ! s\nd :i* 0 he>d at diff]5t po9ts r\nd ab\t ! focus4 ,^! s\nds appe> to h be5 ( ! nature ( sudd5 explosive reports accompani$ by ru%+1 roll+ s\nds4 ,! =m ( ! area 9 :i* ^! s\nds 7 he>d 0 closely simil> to t ( ! fir/ two isoseismals4 ,except 9 ! c5tral area ( great di/urbance1 no s\nd 0 he>d to accompany ! %ock4 ,^? at ! nor!rn & s\!rn extremity ( ! s\nd area all describ$ :at !y he>d z a #8l[1 grat+1 heavy1 sigh+ ru%1 ( tw5ty to sixty seconds' duration4' ,^? 9 ! middle & t[>ds ! ea/ & we/ b\nd>ies ( ?is area describ$ a s\nd ( ! same tone1 b %ort] & m abrupt1 & accompani$ ) m rumbl+4 ,! nature ( ! argum5ts :i* 7 foll[$ 9 discuss+ ! s\nd obs]vations w be f\nd 9 ! *apt] relat+ to ^! ph5om5a4 ,a portion ( ! argum5t :i* x is difficult to foll[ relates to ! maximum rate at :i* x c be suppos$ possible = a fissure to be r5t 9 rocks1 :i* rate dep5ds on ! d5sity & ela/icity ( ^! rocks & o!r con/ant factors4 ,next x 0 obs]v$ t ! pa?s ( ! waves drawn on ! surface1 al?\gh g5]ally int]sect+ 9 a po9t1 did n d s absolutely1 b along a l9e pass+ ?r\gh ! ma9 focus "s #g miles 9 l5g?4 ,?is1 c\pl$ ) ! obs]vations ( s\nds1 l$ to ! supposition t ! c5tre ( di/urbance1 consid]$ horizontally1 orig9at$ along a curv$ l9e pass+ ?r\gh ! *ief focus & ! v>i\s int]sections ( ! wave pa?s4 ,! la/ ph5om5a br\ght =w>d to assi/ 9 ! solution ( ?is int]e/+ problem 7 a /udy ( ! tremul\s movem5ts t prec$$ & foll[$ ! %ock1 & _! relation to ! s\nd ph5om5a4 ,if ! e>?quake orig9at$ by ! =mation ( a fissure1 aft] ! r5d+ has gone on = a c]ta9 "t ! focal cavity is enl>g$ to a c]ta9 ext5t1 & ! great %ock takes place4 ,?is w\ld be foll[$ by conclud+ tremul\s waves4 ,a succession ( ph5om5a l ^? accompani$ ! %ock ab\t :i* ,mallet writes4 ,by obs]vations su* z ^!1 c\pl$ ) :at has be5 said ab\t ! maximum & mean dep?s ( ! focal cavity1 ,mallet came to ! conclusion t ! focal cavity 0 a fissure1 ! r5d+ op5 ( :i* produc$ ! e>?quake4 ,! v]tical dim5sions ( ?is cavity 7 n m ?an #ec miles1 b 7 probably limit$ to ?ree miles4 ,f ! int]section ( ! wave pa?s ^u ! surface & ! obs]v$ em]g5ces1 ?is fissure foll[$ horizontally a curve ( d\ble flexure1 ab\t n9e geographical miles 9 l5g?4 ,! area ( ?is fissure 0 tw5ty-sev5 geographical miles4 ,! "t ( r5d+ x op5 9 ,ap5n9e lime/one w\ld be ab\t #g seconds1 :i* %\ld be ! same z ! p]iod dur+ :i* tremors 7 felt4 ,! "t actually record$ 0 six or eight seconds4 ,briefly1 ?is is1 !n1 ! l9e ( reason+ :i* 0 foll[$ by ,mallet 9 an inve/igation ! results ( :i* are z int]e/+ z !y are />tl+4 ,s9ce ! l9e ( inve/igation has be5 op5$1 & ! exi/5ce ( new problems has be5 indicat$1 o!r inve/igators1 al?\gh n exactly foll[+ ,mallet's me?od 9 all _! details1 h1 :5 endeav\r+ to atta9 ! same ends1 employ$ simil> weapons4 ,?us1 = example1 ,seeba*1 :5 det]m9+ ! dep? & nature ( ! orig9 ( ! e>?quake ( ,middle ,g]many1 reason$ some:at z foll[s3-- ,_h ! orig9 be5 m or less ( a sph]ical cavity1 !n ! region ( mo/ viol5t di/urbance ^u ! surface w\ld1 accord+ to a !orem we h already m5tion$1 h be5 ^u or ne> a circle ( ab\t #hh miles 9 radius r\nd ! epic5trum4 ,?is region1 h[ev]1 0 f\nd by obs]vation to lie along a curv$ b& ab\t =ty miles 9 l5g?1 altoge!r on "o side ( ! epic5trum4 ,to expla9 ?is anomaly ,seeba* foll[$ ,mallet1 & assum$ t ! orig9 0 n a sph]ical cavity1 b a fissure4 ,! dep? & /rike ( ?is fissure 0 det]m9$ by ! obs]vation t ! area ( greate/ di/urbance 0 along a curv$ l9e ly+ radial to ! epic5trum4 ,su* a condition x 0 assum$ indicat$ t ! fissure ( orig9 mu/ be incl9$ t[>ds ?is area ( greate/ di/urbance4 ,a l9e 0 !n drawn f ?is area to ! c5trum4 ,a second l9e at "r angles to ?is "o gave ! dip ( ! fissure4 ,hf]1 :5 work+ on ! e>?quake ( ,belluno1 came to ! conclusion t ! di/urbance orig9at$ f two faults meet+ ea* o!r at an angle ( #fj4 ,9 ?is det]m9ation he 0 *iefly influ5c$ by ! =m ( a c]ta9 homosei/ :i* 0 ( ! =m ( an elongat$ ellipse met on "o side by a second ellipse1 ! pr9cipal axes ( ! two ellipses giv+ ! /rike ( ! two faults4 ,,*apt] ,,xii4 ,,di/ribution ,,( ,,e>?quakes ,,9 ,,space ,,& ,,"t4 ,g5]al di/ribution ( e>?quakes--,occurr5ce along l9es--,examples ( di/ribution--,italian e>?quake ( #ahgc--;,9 ,tokio--,ext5sion ( e>?quake b\nd>ies--,seismic en]gy 9 relation to geological "t2 to hi/orical "t--,relative frequ5cy ( e>?quakes--,syn*ronism ( e>?quakes--,second>y e>?quakes4 ,g5]al di/ribution ( e>?quakes4--,! records ( e>?quakes collect$ by v>i\s seismologi/s lead u to ! conclusion t at "s "t or o!r e c\ntry & e ocean 9 ! _w has exp]i5c$ seismic di/urbances4 ,9 "s c\ntries e>?quakes are felt daily1 & f :at w be said 9 ! *apt] on e>? pulsations x is n unlikely t e l>ge e>?quake might ) prop] in/rum5tal appliances be record$ at any po9t on ! l& surfaces ( our globe4 ,! area ov] :i* any giv5 e>?quake ext5ds is indet]m9ate4 ,! area ov] :i* an e>?quake is s5sible is sometimes v great4 ,! ,lisbon %ock ( #agee is e/imat$ z hav+ be5 s5sible ov] an area ( #c1cjj miles long & #b1gjj miles wide1 b 9 ! =m ( tremors & pulsations x may h %ak5 ! :ole globe4 ,! regions 9 :i* e>?quakes are frequ5t are indicat$ 9 ! accompany+ map1 :i*1 to a great ext5t1 is a reproduction ( a map drawn by ,mallet4 ,! regions col\r$ ) ! d>ke/ t9t are ^? :]e great e>?quakes are ! mo/ frequ5t4 ,! actual numb] ( e>?quakes :i* h be5 felt 9 ! diff]5tly col\r$ areas are giv51 :5 speak+ ( ! relation ( seismic en]gy to season4 ,:5 look+ at ?is *>t x mu/ be rememb]$ t if we 7 to make a detail$ map ( any "o ( ! diff]5t c\ntries :]e e>?quakes are frequ5t1 we %\ld f9d 9 x all ! diff]5ces t we obs]ve 9 ! g5]al *>t4 ,= in/ance1 "o portion ( ,japan1 :]e p]haps sixty %ocks are felt p] ye>1 w\ld be col\r$ ) a d>k t9t1 :il/ o!r portions ( ! same c\ntry1 :]e !re is only "o slight %ak+ felt e few ye>s1 w\ld be left almo/ uncol\r$4 ,! black dots indicat+ ! position ( volcanic v5ts are ev5 m g5]al 9 _! signification ?an ! t9t$ areas4 ,pr(essor ,haughton gives = ! _w a li/ ( #djg volcanoes1 #bbe ( :i* are active4 ,^! numb]s are ! same z ^? giv5 by ,a4 von ,humboldt4 ,( ! active volcanoes #agb are on ! m>g9 ( ! ,pacific1 & ( ! total numb] eight are 9 ,japan4 ,f my own obs]vations 9 ,japan indep5d5tly ( ! ,kurile ,isl&s1 ,i h enum]at$ fifty-?ree volcanoes :i* are ei!r active or h be5 active )9 a rec5t p]iod4 ,9 a few ye>s' "t ?is li/ w probably be increas$4 ,i m5tion ?is fact to %[ h[ v imp]fect our k is respect+ ! numb] ( volcanic v5ts exi/+ on our globe4 ,if we 7 9 a position to indicate ! volcanoes :i* _h be5 9 eruption dur+ ! la/ #d1jjj ye>s1 ! probability is t !y w\ld numb] sev]al ?\s&s r ?an f\r or five hundr$4 ,an inspection ( ! map %[s t e>?quakes *iefly occur 9 volcanic & m\nta9\s regions4 ,! mo/ e>?quake-%ak5 regions ( ! _w =m ! b\nd>ies ( ! ,pacific ocean4 ,x may be rem>k$ t ^! b\nd>ies slope b5ea? ! neighb\r+ ocean at a mu* /eep] angle ?an ! b\nd>ies ( c\ntries :]e e>?quakes occur b seldom4 ,! coa/s ( ,s\? ,am]ica1 ,kams*atka1 ! ,kuriles1 ,japan1 & ! ,s&wi* ,isl&s1 = example1 h slopes b5ea? ! ,pacific f "o 9 tw5ty to "o 9 ?irty4 ,! coa/s ( ,au/ralia1 ,sc&9avia1 & ! ea/]n p>ts ( ,s\? ,am]ica1 :]e e>?quakes are practically unkn[n1 h slopes f "o 9 fifty to "o 9 two hundr$ & fifty4 ,_m e>?quakes h tak5 place 9 mid-ocean4 ,9 ! ,atlantic ,ocean ,m4 ,p]rey has giv5 ab\t #adj in/ances ( su* occurr5ces4 ,! majority ( ! e>?quakes :i* %ake ,japan appe> to h _! orig9 9 ! neighb\r+ ocean4 ,if we c\ld draw a map ( e>?quake orig9s1 x is probable t ! great] numb] ( ! m>ks indicat+ ^! orig9s w\ld be f\nd to be suboceanic & along l9es p>allel to ! %ores ( cont95ts & isl&s :i* rise /eeply f ! b$ ( deep oceans4 ,9 c\ntries l ,switz]l& & ,india1 our m>ks w\ld hold a relation%ip to ! m\nta9s ( ^! c\ntries4#hi ,look+ at ! broad features ( ! globe1 we see on its surface _m va/ depressions4 ,"s ( ^! sauc]-l holl[s =m l& surfaces1 z 9 c5tral ,asia4 ,! majority ( ^!1 h[ev]1 are occupi$ by ! oceans4 ,active volcanoes *iefly occur ne> ! rim ( ! holl[s :i* h ! /eepe/ slopes4 ,! majority ( e>?quakes probably h _! orig9 on or ne> ! bottom ( ^! slopes4 ,to ^!1 h[ev]1 !re are exceptions1 z = in/ance ! e>?quakes 9 ! ,alps1 9 ! hills ( ,scotl&1 & ! %ak+s :i* are occasionally felt 9 c\ntries l ,egypt4 ,! e>?quakes :i* %ake ! bord]s ( ! ,pacific h _! orig9s 91 & _! effects are almo/ exclusively felt on1 ! sides ( ! b\nd+ ridge fac+ ?is ocean4 ,9 ,japan x is ! ea/]n sides ( ! isl&s :i* suff]1 ! we/]n side be+ almo/ z free f ^! convulsions z ,engl&4 ,simil> rem>ks may be made ab\t ! ea/]n side ( ,s\? ,am]ica1 especially ! s\!rn portion ( ! cont95t4 ,at ,bu5os ,ayres1 = example1 !re has be5 no di/urbance s9ce ,m5doza 0 de/roy$1 "s tw5ty ye>s ago4 ,9 ,briti% ,guiana slight %ocks are occasionally felt 9 ! l[ delta :i* =ms ! settl$ portion ( ! colony1 b !y are extremely r>e4 ,di/urbances 9 l9es or zones4--,x has (t5 be5 obs]v$ t di/urbances are propagat$ along ! l5g? ( m\nta9s or valleys1 & x is b seldom t e>?quakes cross !m transv]sely4 ,?us ! valleys ( ! ,rhone1 ! ,rh9e1 & ! ,danube are l9es along :i* di/urbances travel4 ,! major axes ( ! elliptical areas ( di/urbances :i* h %ak5 ,india h a g5]al direction p>allel to ! valley ( ! ,ganges along ! flanks ( ! ,himalayas4 ,! di/urbances :i* h %ak5 ,london appe> to h be5 *iefly ea/ & we/1 or along ! valley ( ! ,?ames4 ,9 ,s\? ,am]ica ! l9e ( di/urbance is along ! we/]n sides ( ! ,&es4 ,ano!r l9e is along ! nor!rn coa/ ( ! cont95t ?r\gh ,&alusia & ,c>accas t[>ds ! ,antilles & ,tr9idad4 ,! %ocks ( ! ,pyr5ees are *iefly felt along ! s\!rn side ( ^! m\nta9s4 ,9 ! middle & on ! nor!rn side !y are b seldom felt4 ,?is propagation 9 l9es or zones may 9 c]ta9 cases be app>5t r ?an real4 ,?us ! nor? & s\? ranges ( m\nta9s 9 ,japan are m\nta9s almo/ simultane\sly %ak5 along _! ea/]n flanks1 giv+ ! impression t an e>?quake _h orig9at$ simultane\sly f a fissure p>allel to ?is l9e1 or else1 />t+ at "o end1 _h run d[n _! l5g?s4 ,"t obs]vations h1 h[ev]1 %[n t su* di/urbances _h _! orig9 at "s di/ance 9 ! ocean1 &1 travell+ inw>ds1 _h rea*$ all po9ts on ! flanks ( ^! m\nta9s almo/ simultane\sly4 ,! same explanation w probably hold = ! s-call$ l9e> di/urbances ( we/]n ,s\? ,am]ica4 ,all e>?quake di/urbances h probably a t5d5cy to radiate f _! s\rce1 & are only prev5t$ f do+ s by meet+ ) heavy m\nta9\s di/ricts1 :i* by _! mass & /ructure absorb ! en]gy communicat$ to !m4 ,mu* en]gy is also lo/ by em]g5ce on ! op5 flanks ( a range ( m\nta9s4 ,r ?an say t high m\nta9s (t5 b\nd ! ext5sion ( an e>?quake1 or t e>?quakes appe> to run along ! flanks ( su* m\nta9s1 we might say t e>?quakes h b\nd>ies p>allel to ! /rike ( ! rocks 9 a giv5 di/rict1 t su* a direction is ! "o 9 :i* ! propagation is ! easi]4 ,rossi is ( op9ion t volcanic fractures play an important "p 9 gov]n+ ! di/ribution ( seismic di/urbances4 ,:5 a volcano is =m$1 a s]ies ( />like fractures are =m$ r\nd ! c5tral crat]4 ,second>y crat]s may indicate ! l9e ( ^! fissures4 ,! m\nta9s ab\t ,rome are reg>d$ z typical ( ?is radial /ructure4 ,! m di/ant ! second>y crat]s are f ! c5tre ( ! sy/em1 ! small] w !y be1 & also ! y\ng]4 ,if two fissures int]sect we get a l>g] crat] at ! junction4 ,e>?quakes are propagat$ along ! direction ( ^! fissures1 :il/ ! ris+ & fall+ ( ^! lips ?r[ (f transv]se waves4 ,rossi adduces obs]vations :i* appe> to meet ) explanation on su* suppositions4 ,suess1 :o has writt5 ^u ! e>?quakes ( l[] ,au/ria1 %[s h[ ! majority ( ! di/urbances h _h _! orig9 along c]ta9 l9es :i* =m a break 9 ! cont9uity ( ! ,alps4 ,"o l9e runs nor?-ea/ f ,bruck t[>ds ,vi5na4 ,ne> ,wi5] ,neu/adt1 :]e ! greate/ numb] & heavie/ %ocks h occurr$1 ?is l9e is met by a nor?-nor?-we/ l9e cross+ ! ,danube & foll[+ ! valley ( ! riv] ,kamp4#ij ,hoeff] has drawn simil> l9es f ! head ( ! ,adriatic1 "o set runn+ nor?-nor?-ea/ to int]sect ne> ,lits*au1 & ! o!r nor?-nor?-we/ to int]sect ne> ,frank=t 9 ! valley ( ! ,rh9e4#ia ,examples ( di/ribution4--,a curi\s example ( ! di/ribution ( seismic movem5t is t ( ! e>?quake ( ,m>* #ab1 #ahgc1 work$ out by ,pr(essor ,p4 ,a4 ,s]pi]i4 ,?is e>?quake appe>s to h be5 simultane\sly felt on ! ,dalmatian coa/ & 9 c5tral ,italy1 9 a region ly+ nor?-ea/ f ,rome & s\?-ea/ f ,flor5ce4 ,9 bo? ( ^! areas ! motion 0 f s\?-ea/ to nor?-we/4 ,! %ock !n radiat$ f ! c5tral ,italian regions1 s t at places on ! we/]n %ore ( ! ,adriatic x 0 felt aft] x _h be5 felt on ! ,dalmatian coa/4 ,_m explanations might be (f]$ = ?is peculi> di/ribution ( seismic activity4 ,possibly ! %ock orig9at$ at a great dep? b5ea? ! b$ ( ! s\!rn "p ( ! ,adriatic1 & by foll[+ exi/+ l9es ( weakness simultane\sly rea*$ ! surface ( ! e>? 9 c5tral ,italy & ,dalmatia4 ,9 ,tokio1 :i* is built p>tly on a flat pla91 p>tly 9 valleys d5ud$ f a l[ tablel&1 & p>tly on ! spurs ( ! tablel& itself1 ! di/ribution ( e>?quakes is a subject yet requir+ att5tion4 ,sometimes x has happ5$ t p]sons 9 "o h\se h be5 suffici5tly al>m$ to escape into ! op5 air1 :il/ o!rs1 n m ?an a mile di/ant1 h n be5 aw>e t ! city _h be5 %ak54 ,illu/ration3 ,,fig4 #cd4 ,areas almo/ simultane\sly /ruck f ,s4,e4 to ,n4,w4 graphic ,subsequ5t radial di/urbance graphic ,ext5sion ( e>?quake b\nd>ies4--,natural ob/ructions :i* may be suffici5t to ret>d small e>?quakes may 9 c]ta9 in/ances n be f\nd suffici5t to ret>d ! l>g] di/urbances4 ,?us ! %ocks ( ,calabria are usually only felt on ! we/]n side ( ! ,ap5n9es1 b in/ances h occurr$ :5 !y h cross$ ?is b>ri]4 ,9 #ahja ! e>?quake ( ,cumana cross$ a bran* ( ! coa/ range4 ,sometimes e>?quake b\nd>ies give way1 & c\ntries :i* !y %elt]$ subsequ5tly become expos$ to all di/urbances4 ,! true explanation ( ?is is probably 9 a %ift+ ( ! c5tre ( seismic activity4 ,?us up to ,decemb] #ad1 #agig1 al?\gh ,cumana 0 (t5 deva/at$1 ! p59sula ( ,araya 0 n hurt4 ,on ?is date ,araya comm5c$ to suff]1 & has cont9u$ to suff] ev] s9ce4 ,fu*s gives an example ( ! movem5t ( a seismic c5tre 9 ! case ( ! ,calabrian e>?quake4 ,! fir/ %ock comm5c$ ne> ,oppi$o1 ! second %ock comm5c$ f\r or five miles f>!r to ! nor?1 & ! ?ird %ock _h its orig9 five or six miles /ill f>!r1 ne> to ,girifalco4 ,,*apt] ,,xiii4 ,,di/ribution ,,( ,,e>?quakes ,,9 ,,"t 7cont9u$74 ,seismic en]gy 9 relation to geological "t4--,if we admit t seismic en]gy is only a =m ( volcanic en]gy1 x mu/ also be admitt$ t any cause t5d+ to produce a g5]al decrease 9 ! am\nt ( ! latt] w also produce an alt]ation 9 ! am\nt ( ! =m]4 ,! nebul> hypo!sis ( ,laplace tells u t ! sol> sy/em is ! result ( ! :irl+ ( a heat$ gase\s mass1 :i* z x cool$ cont9ually contract$ & consequ5tly :irls ! fa/]4 ,) ?is hypo!sis be=e u1 we und]/& :y all ! planets & _! satellites h a simil>ity 9 ! directions ( _! movem5ts1 :y !y revolve ne>ly 9 ! same plane1 9 orbits ne>ly circul>1 :y "s h a flatt5$ figure & are surr\nd$ by r+s or belts1 :y ! ext]ior planets %\ld h a great] velocity ( rotation1 a great] numb] ( satellites1 & a less d5sity z comp>$ ) ! int]ior planets1 ! simil>ity ( ! elem5ts 9 meteoric /ones1 ! sun1 ! />s1 & ^? f\nd ^u our e>?1 & la/ly :y !re %\ld be an increase 9 temp]ature z we desc5d into our e>?4#ib ,?is increase 9 temp]ature z we desc5d into ! e>? z d$uc$ f _m obs]vations appe>s to be ab\t #a ,f4 = e fifty or sixty feet ( desc5t4 ,to expla9 ?is & o!r k9dr$ ph5om5a x is assum$ t ! e>? 0 once v mu* hott] ?an x is at pres5t1 & to rea* its pres5t /age x has be5 gradually cool+4 ,z ! laws ( cool+ are p]fectly kn[n1 to calculate h[ _m ye>s x mu/ h tak5 a body l our e>? to cool d[n to its pres5t temp]ature is a def9ite problem4 ,sir ,william ,?omson1 />t+ ) ! temp]ature ( #g1jjj ,f41 :5 all ! rocks ( ! e>? mu/ h be5 molt5 & a sk9 or cru/ ^u ! surface1 su* z is s quickly produc$ ^u ! surface ( molt5 lava1 f9ds by calculation t ! "t tak5 to rea* ! pres5t temp]ature mu/ h be5 ab\t "o hundr$ million ye>s4 ,into ?is p]iod he & o!r physici/s desire to compress ! hi/ory ( all ! /ratifi$ deposits4 ,geologi/s f9d ?is p]iod too %ort4 ,o!rs seek+ to reconcile ! views ( physici/s & geologi/s endeav\r to %[ t ! v>i\s ag5cies engag$ 9 degrad+ rocks & accumulat+ s$im5ts 9 =m] ages are n to be judg$ ( by ! ag5cies we n[ see ar\nd u2 9 =m] times !y 7 m active4 ,at "o p]iod ! ela/ic tides 9 ! e>? may h be5 s great t !y result$ 9 ! fractur+ (f f our planet its satellite ! moon1 & subsequ5tly ! moon1 act+ on ! wat]s ( ! e>?1 may1 ev5 z late z #aej1jjj ye>s ago1 h produc$ e ?ree h\rs tides #aej feet 9 height4 ,:atev] may be ! value ( ! figures "h quot$1 reason+s l ^! br+ u to ! conclusions t ! v>i\s ag5cies :i* we n[ "k to be act+ ^u our e>? 7 once f> m pot5t ?an !y are at pres5t1 & if ! moon1 z a produc] ( ela/ic tides1 has any influ5ce ^u ! occurr5ce ( e>?quakes1 x mu/ h _h a mu* great] influ5ce 9 bygone times4 ,we might speak simil>ly ) reg>d to ! int]nal heat ( ! e>?4 ,f ! pres5t heat gradi5t ( our globe x is possible to calculate h[ mu* heat fl[s f ! e>? e ye>4 ,?is is equival5t to a quantity :i* w\ld raise a lay] ( wat] #fg c5timetres ?ick1 cov]+ ! :ole ( our globe1 f a temp]ature ( #j to #ajj ,c4 ,simil>ly1 we might calculate ! quantity ( heat :i* w\ld be lo/ :5 ! av]age heat gradi5t1 in/ead ( be+ #a ,f4 = fifty feet ( desc5t1 0 #a ,f4 = tw5ty-five feet ( desc5t4 ,we might also calculate h[ _m ye>s ago x 0 s9ce su* a gradi5t exi/$4 ,! g5]al result :i* we %\ld arrive at w\ld be t 9 pa/ ages ! loss ( heat 0 m rapid ?an x is at pres5t4 ,n[ ! contraction ( a body z x cools is = l[ temp]atures proportional to its loss ( heat1 & ?is law is also probably true = contraction z x takes place f high temp]atures4 ,contraction be+ m rapid1 x is probable t ph5om5a l elevations & depressions w\ld be m rapid ?an !y are at pres5t1 & g5]ally all *anges due to plutonic action1 z has already be5 po9t$ out by ,sir ,william ,?omson1 mu/ h be5 m active4 ,we h1 !re=e1 e reason to imag9e t e>?quakes :i* belong to ! category ( ph5om5a "h ref]r$ to 7 also num]\s & occurr$ on a gr&] scale dur+ ! e>li] /ages ( ! _w's hi/ory ?an !y d at pres5t1 & seismic & volcanic en]gy1 :5 consid]$ 9 ref]5ce to long p]iods ( "t1 is probably a decreas+ en]gy4 ,9 mak+ ?is /atem5t we mu/ n ov]look ! fact t 9 geological "t1 z te/ifi$ by ! records ( our rocks1 volcanic action1 & ) x probably seismic action1 has be5 cont9ually %ift+1 fir/ appe>+ 9 "o area & !n 9 ano!r1 & ev5 9 ! same area we h evid5ce to %[ t ^! h p]iods ( activity & repose successively succe$+ ea* o!r4 ,?us 9 ,brita91 dur+ ! ,palozoic times1 we h _m evid5ces ( an int5se volcanic activity4 ,dur+ ! ,mesozoic or ,second>y p]iod volcanic en]gy appe>s to h subsid$1 to wake up ) r5ew$ vig\r 9 ! ,ca9ozoic or ,t]ti>y p]iod4 ,dur+ ?is latt] p]iod x is n at all improbable t ,scotl& 0 9 pa/ times z rem>kable = its e>?quakes z ,japan is at ! pres5t day4 ,lat] on x w also be %[n t e>?quakes are concomitant ph5om5a1 ) ^? elevatory processes :i* we h reason to believe are sl[ly go+ on 9 c]ta9 portions ( ! e>?'s cru/4 ,if1 !re=e1 we are able by ! exam9ation ( ! rocks :i* con/itute ! accessible portions ( our globe to det]m9e :i* p]iods 7 *>act]is$ by elevation1 we may assume t su* p]iods 7 also p]iods ( seismic activity4 ,among/ ^! p]iods we h ^? 9 :i* v>i\s m\nta9 ranges appe>$4 ,?us ! ,grampians1 & ! m\nta9s ( ,sc&9avia1 7 probably produc$ be=e ! deposition ( ! ,old ,r$ s&/one4 ,! ,urals 7 upheav$ prior to ,p]mian times4 ,! *ief upheaval 9 ! ,alps took place aft] ,eoc5e times4 ,! ,rigi & o!r sub-,alp9e m\nta9s 7 =m$ aft] ! deposition ( ! ,mioc5e b$s4 ,ab\t ?is same "t ! ,himalayas 7 upheav$4#ic ,! e>?quakes :i* f "t to "t %ake ^? new] m\nta9s app>5tly indicate t ! process ( m\nta9-mak+ is h>dly end$4 ,seismic en]gy 9 relation to hi/orical "t4--,! di/ribution ( seismic en]gy ) reg>d to hi/orical "t is a subject :i* has be5 v c>efully exam9$ by ,mallet1 :o collect$ toge!r a catalogue ( betwe5 six & sev5 ?\s& e>?quakes1 embrac$ betwe5 ! p]iods ,b4,c4 #afjf & ,a4,d4 #ahej4 ,! e>?quake ( ,b4,c4 #afjf 0 on ! occasion ( ! deliv]y ( ! law at ,m\nt ,s9ai4 ,betwe5 ,b4,c4 #afjd & ,b4,c4 #aehf an e>?quake probably occurr$ 9 ,arabia1 :5 ,korah1 ,da?an1 & ,abiram 7 swall[$ up4 ,ano!r biblical record is t ( ,b4,c4 #aeff1 :5 ! walls ( ,j]i*o 7 ov]?r[n4 ,! e>lie/ records f ,*9a is 9 ,b4,c4 #eie2 9 ,japan ,b4,c4 #bhe2 9 ,india ,a4,d4 #hid4 ,by us+ ! numb] ( e>?quakes :i* h be5 record$ 9 ea* c5tury z ord9ates1 ,mallet con/ruct$ a curve1 :i* app>5tly %[s a cont9ual increase 9 seismic en]gy1 especially dur+ rec5t times4 ,?is1 ,mallet rem>ks1 contradicts all ! analogies ( ! physics ( ! globe1 & po9ts out t ! rapid increase 9 ! numb] ( e>?quakes 9 latt] ye>s is *iefly due to ! great] numb] ( records :i* h be5 made1 & ! increase ( ! area ( obs]vation4 ,no d\bt _m ( ! records made by ! anci5ts h be5 lo/4 ,if we comp>e ,mallet's records1 z he invites u to d1 ) ! great outl9es ( human progress1 we see t ! two increase simultane\sly1 & we come to ! conclusion t1 tak5 z a :ole1 dur+ ! hi/orical p]iod ! seismic activity ( ! _w has be5 tol]ably con/ant4 ,^! conclusions1 bas$ on ! evid5ce at our comm&1 are n to be confut$4 ,if1 h[ev]1 in/ead ( consid]+ ! seismic en]gy ( ! :ole _w1 we consid] ! seismic en]gy ( p>ticul> areas1 x seems reasonable to expect t 9 c]ta9 in/ances sometimes a decrease & sometimes an increase 9 ?is en]gy might be discov]$1 especially1 p]haps1 9 areas :i* are highly volcanic4 ,9 ,france we "k t volcanic activity ceas$ at a p]iod closely bord]+ on hi/orical times1 & x is n unlikely t seismic activity may h ceas$ at a correspond+ "t4 ,9 a c\ntry l ,japan1 x is possible t 9 "o di/rict seismic en]gy may be on ! increase1 :il/ 9 ano!r ^u ! decrease4 ,9 a c\ntry l ,engl&1 x is probable t ! seismic /ate is con/ant1 &1 :atev] *anges may be n[ occurr+1 !y are tak+ place at s sl[ a rate t1 ev5 if our records ( ! hi/orical p]iod 7 complete1 we c\ld h>dly be expect$ to f9d ^! *anges suffici5tly m>k$ to be obs]vable4 ,= purposes ( ref]5ce1 & also = exam9+ ! pres5t "q1 ! table1 page #bdj1 has be5 compil$4 ,! e>?quakes giv5 are *iefly ^? :i* h be5 record$ 9 hi/ories z be+ m or less de/ructive4 ,9 ! second column ( ?is table w be se5 ! numb] ( e>?quakes :i* h occurr$ 9 ,japan dur+ ea* c5tury1 ! c5turies be+ m>k$ 9 ! fir/ column4 ,9 columns #c to #ah inclusive are giv5 ! numb] ( e>?quakes :i* h occurr$ dur+ diff]5t c5turies 9 ! v>i\s c\ntries & di/ricts m5tion$ at ! head ( ea* column4 ,^! latt]1 :i* are tak5 f ! writ+s ( ,mallet1 are giv5 = ! sake ( comp>ison ) ! ,japanese e>?quakes4 ,if we comm5ce ) ! sev5? c5tury 9 ! column = ,japan1 we see t a great increase 9 ! numb] ( e>?quakes1 z we come t[>ds ! pres5t "t1 is n s obs]vable z x is 9 ! o!r columns4 ,key3 #a ,c5turies #b ,japan #c ,sc&9avia & ,icel& #d ,briti% ,isles & ,nor!rn ,isles #e ,spani% ,p59sula #f ,france1 ,belgium1 ,holl& #g ,rh9e ,bas9 #h ,switz]l& & ,rh9e ,bas9 #i ,danube ,bas9 #aj ,italy1 ,sicily1 ,s>d9ia1 & ,malta #aa ,supplem5tal table = ,italy1 ,s>d9ia1 & ,malta #ab ,turco-,hell5ic ,t]ritory1 ,syria1 gean ,isles1 & ,levant #ac ,unit$ ,/ates & ,canada #ad ,mexico & ,c5tral ,am]ica #ae ,antilles #af ,cuba #ag ,*ili & ,la ,plata ,bas9 #ah ,nor!rn ,zone ( ,asia #ai ,approximate ,int5sity 9 ! ,kioto ,di/rict ( ,japan ---------------------------------------- ----------- #a #b #c #d #e #f #g #h #i #ajaa #abacad #aeaf #agahai ---------------------------------------- ----------- ,i4 #a -- ---- ---- -- -- ---- ------ ---- ------ ,,ii4 -- -- ---- ---- -- -- ---- ------ ---- ------ ,,iii4 #a -- ---- ---- -- -- ---- ------ ---- ------ ,,iv4 -- -- ---- ---- -- -- #f-- #bc---- ---- ------ ,v4 #a -- ---- #a-- -- -- #e-- #ai---- ---- ------ ,,vi4 #a -- ---- #f-- -- #c-- #bg---- ---- ------ ,,vii4 #ab -- ---- ---- -- #a-- #h---- ---- ----#ae ,,viii4 #aa -- ---- ---- -- #b #a #ab---- ---- ----#ag ,,ix4 #dj -- ---- #ba-- #ai #f-- #g---- ---- ----#fj ,x4 #ag -- ---- #b-- #bai #c #c #e---- ---- ----#bd ,,xi4 #bj -- #h #c #af-- #i #g #e #ah---- ---- ----#bh ,,xii4 #ah -- #aa #d #ab-- #h #ahbb #bc---- ---- ----#bj ,,xiii4 #af #ae #c #i-- #c #aebf #ac---- ---- ----#af ,,xiv4 #ai #d #h #ba-- #ah #bjea #h---- ---- ----#be ,,xv4 #cfbh #a #d #ad-- #ab #ahdg #aa---- ---- ----#bi ,,xvi4 #ag #haj #faaj #eb #ce #cb #e #bb-- #f #a #d #e--ag ,,xvii4 #bf #adaj #iabiabj #caaba #i #ecaj #g #af #d #i--aa ,,xviii4#caaaa #fcicbcggaada #hhdchbjabdhhbd #he #b #ajcb #h ,,xix4 #bgaacaajhebaahaagcadecijhhaideacjadeeja gjeg #h ---------------------------------------- ----------- ,! explanation = ?is probably lies 9 ! fact t ,japan has practis$ civilis$ arts = a long] p]iod ?an _m ( ! ,european & o!r c\ntries m5tion$ 9 ! table4 ,9 ,japan1 no d\bt1 ! records ( lat] ye>s h be5 m p]fect ?an !y 7 9 e>ly times1 b ?is1 al?\gh s pot5t an effac] ( :at 0 probably ! true /ate ( natural ph5om5a 9 ! case ( ,europe1 has n q oblit]at$ ! tru? 9 ,japan2 = in/ead ( an app>5t increase ( seismic en]gy s9ce e>ly times x %[s a slight decrease4 ,to draw up a table ( e>?quakes su* z ! "o :i* has j be5 giv51 & !n1 aft] ! inspection ( x1 draw conclusions z to :e!r !re has be5 an increase or decrease 9 seismic en]gy1 is1 h[ev]1 h>dly a j me?od ( reason+4 ,! e>?quakes1 tak5 z !y are1 = ! :ole ( ,japan1 repres5t a collection ( places "s ( :i* are #a1jjj miles ap>t4 ,:5 we consid] t _m e>?quakes :i* occurr$ at "o end ( ?is l9e 7 nev] felt at ! o!r end1 9 ord] to ju/ly e/imate ! p]iodicity ( seismic ph5om5a x w\ld seem t we ought ei!r to take "s p>ticul> seismic area or else ! :ole _w4 ,! p>ticul> area :i* has be5 tak5 is t ( ,kioto 9 ,c5tral ,japan1 & ! e>?quakes :i* h be5 felt !re are enum]at$ 9 ! table4 ,9 ord] to %[ ! v>iation 9 seismic activity ( ?is di/rict a curve has be5 plott$1 fig4 #ce1 ) ord9ates equal to ! values giv5 = ! ,kioto e>?quakes dur+ succe$+ c5turies4 ,! upp] po9ts ( ^! asc5d+ & desc5d+ l9es are jo9$ by a free curve4 ,! l[] po9ts are simil>ly jo9$4 ,! po9ts ( bisection ( ord9ates drawn betwe5 ^! two curves are tak5 z po9ts 9 a curve to %[ ! true secul> *ange 9 seismic en]gy4 ,illu/ration3 ,,fig4 #ce4--;,curve ( ,seismic ,int5sity = ,kioto4 ,by look+ at ?is wavy l9e x w be se5 t ! int]vals betwe5 maxima & m9ima are clos] toge!r 9 e>ly times ?an !y are lat] on4 ,?us1 betwe5 ! eigh? c5tury & ! n9? c5tury1 po9ts ( maximum & m9imum seismic ef=ts occurr$ at times a c5tury ap>t1 :il/ lat] on1 f ! elev5? to ! fifte5? c5tury1 !y 7 at int]vals ( #cjj ye>s ap>t4 ,by inspect+ ei!r ! wavy l9e or ! resultant curve1 x w be se5 t s9ce ! n9? c5tury d[n to ! pres5t "t !re has be5 a decid$ decrease 9 seismic en]gy4 ,f ! n9? c5tury d[n to ! fifte5? c5tury ?is decrease is repres5t$ by a regul> curve4 ,at ?is po9t1 h[ev]1 ! decrease becomes slightly m rapid1 & is repres5t$ by a second curve4 ,if1 in/ead ( calculat+ ord9ates = my curve1 9 :i* int5sity has be5 consid]$1 simply ! numb] ( e>?quakes are c\nt$1 a simil> result is obta9$4 ,f ?is x appe>s t ! rate at :i* seismic en]gy decreas$ dur+ ! la/ #ejj ye>s 0 ab\t ! same z t at :i* x decreas$ dur+ ! #ejj ye>s previ\s to ?is p]iod4 ,if ! li/s = ! ,italian & ,turco-,hell5ic di/ricts c\ld be simil>ly analys$1 & ! e>?quakes ( any p>ticul> di/rict pick$ out f ! o!rs1 x is v probable t a simil> decrease or alt]ation 9 seismic en]gy might be obs]v$4 ,provid$ t we h at our disposal records ( ! v>i\s e>?quakes :i* h occurr$ 9 any giv5 di/rict dur+ a suffici5tly long p]iod ( "t1 "o conclusion t we may expect to arrive at is t we %all be able to trace "s v>iation 9 ! seismic activity ( t di/rict4 ,= ! ,kioto area1 x has be5 %[n t !re is a dim9ution 9 seismic activity1 ,9 o!r di/ricts1 h[ev]1 !re may possibly be an increase4#id ,relative frequ5cy ( e>?quakes4--,a "q :i* is ( great int]e/ to ^? :o dwell 9 %ak5 di/ricts is z to h[ (t5 di/urbances may be expect$ to occur4 ,f a g5]al exam9ation ( ?is "q1 consid]+ ! e>?quakes ( ! :ole _w4 ,mallet arriv$ at ! foll[+ conclusions3-- #a4 ,:ile ! smalle/ or m9imum p>oxysmal int]vals may be a ye> or two1 ! av]age int]val is f five to t5 ye>s ( comp>ative repose4 #b4 ,! %ort] int]vals are 9 connection ) p]iods ( few] e>?quakes--n always ) ^? ( lea/ int5sity1 b usually s4 #c4 ,! alt]nations ( p>oxysm & ( repose appe> to foll[ no absolute law d$ucible f ^! curves4 #d4 ,two m>k$ p]iods ( extreme p>oxysm are obs]vable 9 ea* c5tury1 "o great] ?an ! o!r--t ( greate/ numb] & int5sity occurr+ ab\t ! middle ( ea* c5tury1 ! o!r t[>ds ! end ( ea*4 ,! =m ( ! curves :i* ,mallet has drawn seem to indicate t seismic en]gy came 9 sudd5 bur/s1 & !n subsid$1 gradually ga!r+ /r5g? = ano!r exhibition4 ,?is is cont9ually se5 9 ! %ocks exp]i5c$ 9 v>i\s seismic areas--a l>ge %ock1 or ! maximum ( ! activity dy+ out by repeat$ small %ocks on succe$+ days4 ,mr4 ,i4 ,hattori1 writ+ on ! l>ge e>?quakes ( ,japan1 rem>ks t on ! av]age !re has be5 "o l>ge e>?quake e t5 ye>s4 ,!y1 h[ev]1 occur 9 gr\ps1 z %[n 9 ! foll[+ table4 ------------------------------- ,no4 ( %ocks ,p]iod ,int]val ------------------------------- #f ,a4,d4 #hbg-hcf #aj ye>s #f #hhj-hij #aj #d #ajdj-ajdc #d #e #adic-aejg #e #d #aeaj-aeac #d #e #afde-afej #f #e #affb-affd #c #d #ahec-ahef #d ------------------------------- ,dr4 ,e4 ,naumann1 :o has also writt5 on ! e>?quakes 9 ,japan1 rem>ks t if p]iods ( seismic activity d n occur e #dij ye>s1 !re is a repetition ( ! cycle aft] #ihj ye>s1 b !re is mu* v>iability4 ,a p]iod ( #fh ye>s is v m>k$4 ,on ! av]age1 l>ge e>?quakes h occurr$ e #ei ye>s4 ,fu*s gives "s int]e/+ examples ( ! repetition ( e>?quakes at def9ite int]vals1 ( :i* ! foll[+ are examples4 ,sometimes e>?quakes appe> to h repeat$ !mselves aft] #ajj ye>s4 ,"o rem>kable example ( ?is is t ( ,lima1 on ,june #ag1 #aegh1 :i* 0 repeat$ on ! same day 9 ! ye> #afgh4 ,9 ,copiapo x is believ$ t e>?quakes occur e tw5ty-?ree ye>s1 & examples ( su* repetitions are f\nd 9 ! ye>s #aggc1 #agif1 & #ahai4 ,9 ,canada1 ne> to ,quebec1 e>?quakes la/+ =ty days are said to occur e tw5ty-five ye>s4 ,! plateau ( ,ardebil is said to be regul>ly %ak5 by e>?quakes e two ye>s4 ,a4 ,caldcleugh1 writ+ on ! e>?quake ( ,*ili1 9 #ahce1ie rem>ks t ! ,spani>ds fir/ _h ! idea t a great e>?quake occurs e c5tury4 ,aft]w>ds !y ?\ght ! p]iod 0 e fifty ye>s4 ,z a matt] ( fact1 h[ev]1 !re 7 l>ge e>?quakes 9 #ahab1 at ,c>acas2 9 #ahah1 at ,copiapo2 9 #ahbb1 at ,santiago2 9 #ahbg1 at ,bogota2 9 #ahbh1 at ,lima2 9 #ahbi1 at ,santiago2 & 9 #ahcb1 at ,huasco4 ,! av]age p]iod ( seismic di/urbances 9 any c\ntry probably dep5ds ^u ! subt]ranean volcanic activity ( t c\ntry4 ,:5 ! activity is great ! l>ge e>?quakes may occur at %ort int]vals2 b :5 ! activity is small1 z 9 ,engl&1 %ocks ( mod]ate int5sity may n be felt m ?an once or twice p] c5tury4 ,a g5]al idea ( ! relative frequ5cy ( ! l>ge e>?quakes 9 v>i\s p>ts ( ! _w may be easily obta9$ by an inspection ( ! table on page #bdj4 ,betwe5 ! ye>s #ahej & #aheg ,kluge f\nd t 9 ! _w !re _h be5 #d1fbj e>?quakes1 :i* is1 ^u ! av]age1 ne>ly two p] day4 ,?is e/imate ( ! frequ5cy ( e>?quakes ( suffici5t int5sity to be record$ )\t ! aid ( in/rum5ts is1 h[ev]1 mu* bel[ ! tru?4 ,9 ,japan alone !re probably occurs1 z a daily av]age1 a numb] at lea/ equal to t :i* has be5 j giv5 = ! :ole _w4 ,b\ss+ault consid]$ t1 9 ! ,&es1 e>?quakes 7 occurr+ e in/ant ( "t4#if ,to /ate def9itely h[ _m e>?quakes are felt 9 ! _w on ! av]age e day is1 f ! data :i* we h at our comm&1 an impossibility4 ,p]haps !re may be t51 p]haps !re may be #ajj4 ,! "q is "o :i* rema9s to be decid$ by /ati/ics :i* h yet to be compil$4 ,aft] a l>ge e>?quake1 small] %ocks usually occur at %ort int]vals4 ,at fir/ ! succession ( di/urbances are sep>at$ f ea* o!r by p]haps only a few m9utes or h\rs4 ,lat] on1 ! int5sity ( ^! %ocks usually decreases1 & ! int]vals betwe5 !m become great] & great]1 until1 f9ally1 aft] p]haps a few mon?s1 ! seismic activity ( ! area assumes a quiesc5t /ate4 ,! great e>?quake :i* ov]took ,concepcion on ,febru>y #bj1 #ahce1 0 foll[$ by a succession ( %ocks l ^? j ref]r$ to1 !re be+ regi/]$1 betwe5 ! date ( ! de/ructive %ock & ,m>* #d1 #cjj small] di/urbances4 ,dur+ ! tw5ty-f\r h\rs succe$+ ! de/ruction ( ,lima 7,octob] #bh1 #agdf71 #bjj %ocks 7 c\nt$1 & up to ! #bd? ( ,febru>y 9 ! foll[+ ye> #dea %ocks 7 felt4 ,at ,/4 ,?omas1 9 #ahfh1 #bhc %ocks 7 c\nt$ 9 n9e & a qu>t] h\rs4 ,simil> examples might be tak5 f ! description ( almo/ all de/ructive e>?quakes ( :i* we h records4 ,= a l>ge e>?quake to occur1 & n to be accompani$ by a tra9 ( succe$+ e>?quakes1 is exceptional4 ,sometimes we f9d t a l>ge numb] ( small e>?quakes h occurr$ )\t a l>ge "o be+ felt4 ,seismic /orms ( ?is description h happ5$1 ev5 9 ,engl&--= in/ance1 9 ! ye> #agej1 :i* appe>s to h be5 a ye> ( e>?quakes = _m portions ( ! globe4 ,9 ?is ye>1 :i* is kn[n z ! #8e>?quake ye>1' %ocks 7 felt 9 ,engl& z foll[s3 ,on ,m>* #ad1 9 ,surrey2 ,m>* #ah1 9 s\?-we/ ( ,engl&2 ,april #b1 at ,*e/]2 ,june #g1 at ,norwi*2 ,augu/ #bc1 9 ,l9coln%ire2 ,septemb] #cj1 ,nor?ampton%ire4 ,syn*ronism ( e>?quakes4--,"o ( ! fir/ writ]s :o drew att5tion to ! fact t two %ocks ( e>?quakes h be5 felt simultane\sly at di/ant places 0 ,david ,milne1 :o publi%$ a li/ ( ^! occurr5ces4#ig ,9 two in/ances1 ,febru>y & ,m>* #agej1 %ocks 7 simultane\sly felt 9 ,engl& & ,italy4 ,9 ,septemb] #ahcc %ocks appe> to h be5 simultane\sly felt 9 ,engl& & ,p]u4 ,^! & _m o!r simil> examples are discuss$ by ,mallet1 :o ?9ks ) ,milne t ^! co9cid5ces are 9 e probability matt]s ( accid5t4 ,accord+ to ,fu*s1 ,calabria & ,sicily appe> (t5 to h _h e>?quakes at ! same "t1 z = in/ance 9 #aafi1 #aece1 #afch1 :5 ! t[n ,euphemia sank1 & 9 ! ye>s #aggj1 #aggf1 #aghj1 & #aghc4 ,a rem>kable example ( co9cid5ce occurr$ on ,novemb] #af1 #ahbg1 :5 a t]rible e>?quake 0 felt 9 ,columbia1 & at ! same "t a %ock occurr$ on ! ,o*otsk pla9s1 ne>ly antipodal to ea* o!r4 ,kluge also gives a l>ge numb] ( in/ances ( simultane\s e>?quakes2 ?us1 on ,janu>y #bc1 #ahee1 on ! same day t ,well+ton1 ,new ,zeal&1 s sev]ely suff]$1 !re 0 a heavy e>?quake 9 ! ,sieb5geb]ge1 & also 9 ,nor? ,am]ica4 ,to ?is might be add$ ! fact t ! la/ de/ructive e>?quake 9 ,japan occurr$ )9 a few days ( ?is "t4 ,sometimes neighb\r+ c\ntries :]e e>?quakes are common are equally rem>kable by _! utt] want ( syn*ronism4 ,= example1 ,s\!rn ,italy & ,syria are said nev] to be %ak5 simultane\sly4 ,second>y e>?quakes4--,al?\gh x is possible t ! simultane\s occurr5ce ( e>?quakes 9 di/ant regions may sometimes be a matt] ( *ance1 x mu/ also be rem>k$ t ! %ak+ produc$ by "o e>?quake may be suffici5t to cause gr\nd :i* is 9 a critical /ate to give way1 & ?us ! fir/ di/urbance becomes ! orig9ator ( a second e>?quake4 ,admitt+ t an e>?quake1 z x radiates f its c5tre1 may act 9 su* a mann]1 we see t a feeble di/urbance might be ! ultimate cause 9 ! production ( a de/ructive e>?quake1 j z ! di/urbance ( a /one ^u ! face ( a sc>p might1 by its impact ^u o!r /ones1 cause _m tons ( mat]ial to be dislodg$4 ,x is also easy to conceive h[ ! seismic activity ( two di/ricts may be dep5d5t ^u ea* o!r4 ,inasmu* z ^! second>y %ocks are direct effects ( prim>y di/urbances1 !y might h be5 treat$ 9 a previ\s *apt]4 ,z examples ( consequ5t or second>y e>?quakes ,fu*s tells u t :5 small e>?quakes take place 9 ,con/ant9ople & ,asia ,m9or1 e>?quakes are felt 9 ,bukh>e/1 ,galazy1 & ,kron/adt4 ,! great ,lisbon e>?quake also appe>s to h giv5 rise to sev]al consequ5t di/urbances4 ,"o 0 9 ,d]by%ire1 occurr+ at #aa a4m4 ,x 0 suffici5tly viol5t to cause pla/] to fall f ! sides ( a room & a *asm to op5 on ! surface ( ! gr\nd4 ,"s m9]s work+ und]gr\nd 7 s al>m$ t !y endeav\r$ to escape to ! surface4 ,dur+ tw5ty m9utes !re 7 ?ree di/9ct di/urbances4 ,ano!r %ock 0 felt at ,cork4#ih ,al?\gh ^! di/urbances own a consequ5ce ( ! ,lisbon e>?quake !y might prop]ly p]haps be attribut$ to ! pulsations produc$ by ! %ock at ,lisbon1 :i* spread ?r\gh ,engl& & o!r c\ntries )\t be+ felt4 ,! %ocks :i* m5 felt 9 ,new ,zeal& & ,new ,s\? ,wales 9 #ahfh 7 probably second>y %ocks1 due to ! di/urbance at ,arequipa & o!r places on ! ,s\? ,am]ican coa/4 ,^! s-call$ second>y e>?quakes1 al?\gh 9 _m in/ances !y may be due to e>? pulsations produc$ by e>?quake1 or to ! imm$iate s5sible %ak+ ( a l>ge e>?quake1 may p]haps1 9 c]ta9 in/ances1 be attribut$ to "s widespread di/urbance b5ea? ! cru/ ( ! e>?4 ,! occurr5ce ( p]iods :]e all e>?quake c\ntries suff]1 unusual di/urbances indicate ! probability ( su* und]gr\nd ph5om5a4 ,,*apt] ,,xiv4 ,,di/ribution ,,( ,,e>?quakes ,,9 ,,"t 7cont9u$74 ,! occurr5ce ( e>?quakes 9 relation to ! position ( ! heav5ly bodies--,e>?quakes & ! moon--,e>?quakes & ! sun2 & ! seasons2 ! mon?s--,planets & meteors--,h\rs at :i* e>?quakes are frequ5t--,e>?quakes & sun spots--,e>?quakes & ! aurora4 ,! position ( ! heav5ly bodies & ! occurr5ce ( e>?quakes4--,s9ce ! e>lie/ times1 9 se>*+ = ! cause ( v>i\s natural ph5om5a1 man has turn$ 8 en]gies t[>ds ! heav5s4 ,"o ( ! e>lie/ obs]vations 0 ! connection t exi/s betwe5 ! season ( ! ye> & ! motions ( ! heav5ly bodies4 ,tides 7 se5 to be influ5c$ by ! moon4 ,9 lat] times x has be5 discov]$ t p]iods ( maximum magnetic di/urbances occur e t5 or elev5 ye>s ) ! sun spots1 & ,h]r ,kreil1 ( ,vi5na1 tells u our satellite1 ! moon1 has also an influ5ce ^u ! magnet4 ,f day to day we see ! bond connect+ our planet ) ! sun1 ! moon1 & o!r heav5ly bodies :i* are outside u gradually becom+ clos]4 ,inasmu* z _m ph5om5a1 l ! motion ( ! tides1 ! rise & fall ( ! b>omet]1 fluctuations 9 temp]ature1 are all m or less directly connect$ ) ! relative position ( our planet ) reg>d to ! sun & moon1 any co9cid5ce betwe5 ! phases ( ^! bodies & ! occurr5ce ( e>?quakes m or less involves a "t relation%ip ) ! o!r ph5om5a resultant on lun> & sol> influ5ces4 ,e>?quakes & ! position ( ! moon4--,_m e>?quake inve/igators h attempt$ to %[ ! connection betwe5 e>?quakes & ! phases ( ! moon4 ,! fir/ & mo/ successful work] 9 ?is bran* ( seismology 0 ,pr(essor ,alexis ,p]rey1 ( ,dijon1 :o1 aft] _m ye>s ( ardu\s lab\r 9 tabulat+ & exam9+ catalogues ( e>?quakes1 %[$ t e>?quakes 7 m likely to occur at ! foll[+ p]iods ?an at o!rs4 #a4 ,!y are m frequ5t at new or full moon 7syzygies7 ?an at half moon 7quadratures74 #b4 ,!y are m frequ5t :5 ! moon is ne>e/ ! e>? 7p]igee7 ?an :5 %e is f>!/ (f 7apogee74 #c4 ,!y are m frequ5t :5 ! moon is on ! m]idian ?an :5 %e is on ! horizon4 ,^! results 7 obta9$ by ,p]rey aft] analys+ 8 catalogues by ?ree diff]5t & indep5d5t me?ods1 & !y 7 confirm$ by ! report ( a committee appo9t$ by ! ,academy ( ,sci5ces4 ,x mu/1 h[ev]1 be rem>k$ t 9 sev]al in/ances anomalies occur1 & also t ! diff]5ce betwe5 ! numb] ( e>?quakes at any two p]iods is n a v l>ge "o4 ,?us1 = in/ance1 ! annual catalogues compil$ by ,p]rey f #ahdd to #ahdg1 ! e>?quakes 9 p]igee are to ^? 9 apogee z #dg 3 #ci4 ,betwe5 ! ye>s #ahdc & #ahgb ,p]rey f9ds t #c1bij %ocks occurr$ at ! moon's p]igee1 & #c1jae at ! apogee4#ii ,betwe5 #agfa & #ahjj e>?quakes occurr$ z foll[s3-- ,9 ,p]igee #ebf ,apogee #dfe ,! foll[+ table %[s ! results :i* enabl$ ,p]rey to d$uce 8 fir/ law4 ,divid+ ! p]iod ( lunation into qu>t]s1 ) ! "t ( syzygies & quadratures z ! c5tres ( ^! qu>t]s1 he f\nd t ! e>?quakes 7 di/ribut$ z foll[s4 ---------------------------------------- ----------------- ,diff]5ce 9 ,totals ,syzygies ,quadratures fav\r ( ! ,syzygies ---------------------------------------- ----------------- #ahdc-ahdg #a1fjd #hejdh #geceb #fiif #ahdh-aheb #b1jdi #a1jecec #iiedg #ehjf #ahec-aheg #c1jah #a1ecdac #a1dhchg #ejbf #aheh-ahfb #c1adj #a1fjbii #a1ecgda #feih #ahfc-ahfg #b1hde #a1dfcdb #a1chaeh #hahd #ahfh-ahgb #d1eic #b1cccdh #b1beieb #gcif #ahdc-ahgb #ag1bdi #h1hchjc #h1dajig #dbgjf ---------------------------------------- ----------------- ,! report$ e>?quakes betwe5 #agea & #ahdc are %[n to con=m ) ! same rule4#ajj ,julius ,s*midt1 a/ronom] at ,a!ns1 f\nd = ! e>?quakes ( ,ea/]n ,europe & adjac5t c\ntries = ! ye>s #aggf to #ahgc t !re 7 m e>?quakes :5 ! moon 0 9 p]igee4 ,o!r maxima 7 at new moon1 & two days aft] ! fir/ qu>t]4 ,!re 0 a dim9ution at full moon1 & a m9imum on ! day ( ! la/ qu>t]4 ,z "o example ( results :i* are antagoni/ic to ! g5]al results obta9$ by ,p]rey may be quot$ ! results ( an exam9ation by ,pr(essor ,w4 ,s4 ,*apl9 ( ! e>?quake record$ at ! meteorological obs]vatory 9 ,tokio4 ,! li/ ( e>?quakes1 #adc 9 numb]1 ext5d+ ov] a p]iod ( ?ree ye>s1 0 record$ by "o ( ,palmi]i's in/rum5ts4 ,! results 7 z foll[s3-- #a4 ,!re h be5 maxima ( e>?quakes :5 ! moon 0 two & n9e h\rs ea/ & sev5 h\rs we/4 ,at ! upp] transit !re is a m9imum4 #b4 ,consid]+ ! moon's position ) reg>d to ! sun1 at conjunction !re 7 #cb1 at opposition #cg1 & at quadrature #gd4 ,ea/ ( ! m]idian ! maximum 0 at lea/ f\r h\rs4 #c4 ,:5 ! moon 0 nor? ( ! equator ^! 7 #fh1 :5 s\? #hb4 #d4 ,a maximum ( e>?quakes sev5 & elev5 days aft] ! moon's p]igee4 ,! fact t ^! results 7 obta9$ = ! e>?quakes ( a special small seismic area r5d]s !m m int]e/+4#aja ,frequ5cy ( e>?quakes 9 relation to ! position ( ! sun4--,! "q z to :e!r !re is a connection betwe5 ! frequ5cy ( e>?quakes & ! relative position ( ! sun is to a great ext5t id5tical ) ! "q z to ! relative frequ5cy ( e>?quakes 9 ! v>i\s seasons4 ,x is a subject :i* we f9d ref]r$ to by writ]s 9 ! e>lie/ ages4 ,pl9y & ,ari/otle ?\ght t e>?quakes occurr$ *iefly 9 spr+ & autumn4 ,9 lat] times x has be5 a subject :i* has be5 mo/ c>efully consid]$ by ,m]ian1 von ,h(f1 ,p]rey1 ,mallet1 ,volg]1 ,kluge1 & o!rs :o h devot$ att5tion to seismology4 ,9 a rsum ( ! e>?quakes ( ,europe1 & ( ! adjac5t p>ts ( ,asia & ,africa1 f ,a4,d4 #cjf-ahdc1 ,mallet gives ! foll[+ results3-- ---------------------------------------- ------------------------ ,= ,n9ete5? ,c5tury ,= ! :ole p]iod ---------------------------------------- ------------------------ ,w9t] ,sol/ice #agg ,sol/ices #bec ,sol/ices ,spr+ ,equ9ox #aea #cjf #agj #djc ,summ] ,sol/ice #abi ,equ9oxes #aej ,equ9oxes ,autumnal ,equ9ox #afd #cae #aei #cbi ---------------------------------------- ------------------------ ,! above p]iods 7 call$ by ,p]rey critical epo*s1 because z a g5]al result ( 8 rese>*es he f\nd t at su* p]iods !re 0 a great] frequ5cy ( e>?quakes4 ,fu*s1 quot+ f ,kluge's tables1 ext5d+ f #ahej-aheg1 tells u t ! record$ e>?quakes occurr$ z foll[s3-- ,9 ! ,nor!rn ,hemisph]e-- ,equ9oxes #acbd ,sol/ices #abjb ,9 ! ,s\!rn ,hemisph]e-- ,equ9oxes #cja ,sol/ices #bfa ,e>?quakes are1 !re=e1 m frequ5t at ! equ9oxes1 & ?is especially at ! autumnal equ9ox4 ,9 ! nor!rn hemisph]e1 at ! sol/ices1 ! great] numb] ( %ocks occur ab\t ! w9t] sol/ices1 :il/ 9 ! s\!rn hemisph]e1 ab\t ! summ] sol/ices4 ,exceptions1 h[ev]1 are f\nd 9 ,c5tral ,am]ica & ! ,we/ ,indies1 9 ! ,caucasus1 & ! gean ,sea4 ,! idea t e>?quakes _h a p]iodicity dep5d5t ^u ! position ( ! heav5ly bodies is by no means conf9$ to ,europe4 ,9 a ,japanese "w call$ #8,ji%9 ,setsu' 7an op9ion ab\t e>?quakes7 by a prie/ call$ ,t5%o1 x is /at$ t ! relative positions & movem5ts ( ! tw5ty-eight con/ellations ) respect to ! moon cause e>?quakes4 ,?is ,t5%o ass]ts aft] c>eful calculation1 & ,falb tells u t all future e>?quakes c be pr$ict$4 ,9 ! ,kuriles & ,kams*atka1 ,sicily1 & 9 p>ts ( ,s\? ,am]ica1 x is said t ! equ9oxes are reg>d$ z dang]\s seasons4 ,frequ5cy ( e>?quakes 9 relation to ! seasons & mon?s4--,:at is "h said respect+ ! relative frequ5cy ( e>?quakes at ! diff]5t seasons & mon?s is little m ?an an ext5sion & critical exam9ation ( ! results :i* h be5 giv5 respect+ ! frequ5cy ( e>?quakes 9 reg>d to ! position ( ! sun4 ,t !re is a diff]5ce betwe5 ! numb] ( e>?quakes :i* are felt at "o season ( ! ye> z comp>$ ) ^? felt at ano!r is a fact :i*1 z seismoscopic obs]vations are ext5d$1 is becom+ m & m recognis$4 ,"s ( ! m important results :i* 7 arriv$ at by ,mallet f #e1hgi obs]vations made 9 ! nor!rn hemisph]e1 & #bbc 9 ! s\!rn hemisph]e1 may be express$ z foll[s3-- ---------------------------------------- ------------------------ ,maxima ,m9ima ---------------------------------------- ------------------------ ,nor!rn ,hemisph]e ,janu>y1 also a slight ,may1 ,june1 & rise 9 ,augu/ & ,july ,octob] ,s\!rn ,hemisph]e ,novemb]1 also ,may ,m>*1 ext5d+ & ,june ov] "o mon?1 also ,augu/ ---------------------------------------- ------------------------ ,julius ,s*midt1 ( ,a!ns1 :o s c>efully exam9$ ! e>?quakes ( ea/]n ,europe1 came to ! foll[+ conclusions3-- ,= ! e>?quakes betwe5 #abjj & #ahgc1 a maximum on ,septemb] #bf & ,janu>y #ag2 a m9imum on ,decemb] #c & ,june #ac4 ,= ! e>?quakes betwe5 #ahgc & #ahgd1 a maximum on ,m>* #a & ,octob] #a2 a m9imum on ,july #g & ,decemb] #ae4 ,= all ! e>?quakes ( ea/]n ,europe1 a maximum on ,janu>y #c2 a m9imum on ,july #h1 or !re 0 a maximum at p]ihelion & aphelion4 ,:5 ! mon?s are gr\p$ toge!r accord+ to ! seasons1 spr+1 summ]1 autumn1 & w9t]1 we f9d t 9 ! nor!rn hemisph]e ! m9imum is 9 summ] & ! maximum 9 w9t]1 :il/ 9 ! s\!rn hemisph]e 7giv+ ! prop] mon?s correspond+ to its seasons7 we f9d two maxima1 "o at ! comm5cem5t ( w9t]1 & ! o!r at midsumm]1 :il/ ! m9ima are 9 spr+ & autumn4 ,illu/ration3 ,,fig4 #cf4--;,curves ( ,mon?ly ,seismic ,int5sity 7,mallet74 ,9 ! foll[+ table ! diff]5ce 9 ! numb] ( e>?quakes felt at diff]5t seasons is giv5 m 9 detail4 ,9 exam9+ ?is table1 we mu/ rememb] t = c\ntries l ,p]u1 ,*ili1 & ,new ,zeal&1 ly+ 9 ! s\!rn hemisph]e1 ! records giv5 = ! mon?s ,april to ,septemb] correspond to ! w9t] mon?s ( ^? c\ntries4 ,! ,roman num]als indicate ! c5turies betwe5 :i* ! records date4 ---------------------------------------- -------------------------- ,octob] ,april to to ,m>* ,septemb] ---------------------------------------- -------------------------- #a4 ,sc&9avia & ,icel&1 xii-xix #abi #ia #b4 ,briti% & ,nor!rn ,isles1 xi-xix #abc #id #c4 ,belgium1 ,france1 & ,holl&1 iv-xix #cie #bgb #d4 ,rhone ,bas91 xvi-xix #aae #fi #e4 ,switz]l& & ,rh9e ,bas91 ix-xix #cbg #bje #f4 ,danube ,bas91 v-xix #adg #abh #g4 ,spani% ,p59sula1 xi-xiv #aad #hg #h4 ,italy1 ,sicily1 ,s>d9ia1 & ,malta1 ,nor!rn iv-xix #fej #eha ,regions #i4 ,turco-,hell5ic ,t]ritory1 ,syria1 gean ,isles1 & ,levant1 iv-xix #bad #bbb #aj4 ,nor!rn ,zone ( ,asia1 xviii-xix #df #cf #aa4 ,japan 7,tokio area71 #ahgb-ahhj 7small e>?quakes7 #bac #aeg #ab4 ,japan ,b4,c4 #bie-;,a4,d4 #ahgb 7l>ge e>?quakes7 #afe #ahh #ac4 ,alg]ia & ,nor!rn ,africa #bf #bj #ad4 ,unit$ ,/ates & ,canada1 xvii-xix #hf #dh #ae4 ,java1 ,sumatra1 & neighb\r+ ,isl&s1 #ahgc-d-g-h #aid #ahb ,c5tral #af4 ,mexico & ,c5tral ,am]ica1 xvi-xix #bf #bf ,regions #ag4 ,we/ ,indies 7,mallet71 xvi-xix #ajh #aad #ah4 ,we/ ,indies1 xvi-xix #bif #cdc #ai4 ,cuba1 xvi-xix #bh #bc #bj4 ,*ili1 & ,la ,plata ,bas91 xvi-xix #hi #hi ,s\!rn #ba4 ,p]u1 ,columbia1 ,bas9 ( ,amazons1 ,regions xvi-xix #ejf #eda #bb4 ,new ,zeal&1 #ahfi-ahgi #aff #agf ---------------------------------------- -------------------------- ,neglect+ ^? records :i* %[ z _m e>?quakes = ! w9t] mon?s z = ! summ] mon?s1 we see at a glance t g5]ally ! great] numb] ( %ocks h happ5$ dur+ ! cold] seasons4 ,9 ! s\!rn hemisph]e1 s f> z ! records g1 ?is is n true4 ,9 ! nor!rn regions1 out ( f\rte5 examples !re are two exceptions4 ,9 ! c5tral regions !re are two cases :]e ! greate/ numb] ( e>?quakes h be5 record$ 9 ! w9t] mon?s1 & two cases :]e ! greate/ numb] h be5 record$ = ! summ]4 ,altoge!r1 out ( tw5ty-two examples1 !re are only six exceptions to ! rule4 ,^! exceptions altoge!r occur among records _m ( :i* are anci5t1 & are1 !re=e1 m op5 to error ?an li/s :i* h be5 compil$ 9 mod]n times4 ,because small e>?quakes are seldom notic$ by p]sons out 9 ! op5 air1 x might be expect$ t ! numb] ( e>?quakes obs]v$ 9 w>m c\ntries at "o portion ( ! ye> w\ld be equal to ^? obs]v$ 9 any o!r season4 ,su* an argum5t1 h[ev]1 w\ld h>dly apply to mo/ ( ! records :i* are quot$1 z !y ref] to de/ructive di/urbances4 ,if1 h[ev]1 we take ! records made 9 tropical c\ntries f ! table j giv51 we see t 9 su* c\ntries !re h be5 almo/ z _m obs]vations ( e>?quakes at "o season z at any o!r4 ,ano!r fact :i* might be adduc$ aga9/ ! rule t ! great] numb] ( e>?quakes occur dur+ ! w9t] mon?s w\ld be ! comp>ison ( a table ( e>?quakes record$ previ\s to ! n9ete5? c5tury4 ,by do+ ?is we see t = c]ta9 c\ntries ! w9t] rule is inv]t$1 & t ! great] numb] ( %ocks are felt dur+ ! summ]4 ,not)/&+ ^! objections to ,p]rey's conclusions1 ! balance ( evid5ce is 9 fav\r ( 8 g5]al result1 & we may conclude t dur+ ! cold] portions ( ! ye> we may expect m %ak+s ?an dur+ ! w>m] portions4 ,comp>+ ! numb] ( e>?quakes ( w9t] & autumn to ^? ( summ] & spr+1 !y are to ea* o!r 9 ! proportion ( #d 3 #c4 ,a fair] way to exam9e ?is "q1 & to det]m9e :at is probably ! pres5t /ate ( seismic activity 9 our globe1 w\ld be only to consid] ! e>?quakes :i* h tak5 place 9 comp>atively rec5t times1 lay+ especial /ress ^u ^? obs]vations :i* h be5 made ) ! assi/ance ( automatic in/rum5ts1 or ^? :i* h be5 collect$ by p]sons int]e/$ 9 ^! inve/igations4 ,= ?is purpose ! foll[+ table1 %[+ ! di/ribution ( e>?quakes 9 diff]5t c\ntries dur+ ! n9ete5? c5tury1 has be5 compil$4 ,! arrangem5t is m5sual4 ,:]e ! numb] ( e>?quakes 9 any mon? is above ! av]age1 ! numb] is pr9t$ 9 l>ge type2 :]e bel[ ! av]age1 9 small type4 ,,e>?quakes ,,( ,,! ,,n9ete5? ,,c5tury1 ,,*iefly ,,f ,,p]rey4 ,key3 ,jan ,janu>y ,feb ,febru>y ,m> ,m>* ,apr ,april ,may ,may ,jun ,june ,jul ,july ,aug ,augu/ ,sep ,septemb] ,oct ,octob] ,nov ,novemb] ,dec ,decemb] ,ave ,av]age p] mon? ---------------------------------------- -------------------------------------- ,jan,feb,m>,apr,may,jun,jul,aug,sep,oct, nov,dec,ave ---------------------------------------- ------------------------- ,sc&9avia & ,icel& #ag #aa #aa #g #g #f #h #h #aj #aj #aa #f #ic ,briti% ,isles & ,nor!rn ,isles #i #i #aj #g #h #f #e #aa #ab #h #aa #ab #i ,france1 ,belgium1 ,holl& #bg #ag #ba #ac #ac #h #ae #ag #ae #ag #ba #beag ,bas9 ( ! ,rhone #ab #ab #h #c #c #b #b #d #f #f #h #ad #ff ,bas9 ( ! ,rh9e & ,switz]l& #ae #ag #ac #ab #aa #f #ab #aa #aj #ag #bd #bead ,bas9 ( ! ,danube #ad #ae #i #h #ab #h #af #aa #aa #af #aj #abaah ,spani% ,p59sula #aj #e #f #g #d #f #aj #e #i #aa #g #e #g ,italian ,p59sula1 ,sicily1 ,s>d9ia1 & ,malta #dd #dd #dh #dc #dj #cd #da #df #bg #de #bf #cici ,turco-,hell5ic ,t]ritory1 ,syria1 gean ,isl&s1 & ,levant #bb #bj #aj #aj #af #ae #ad #bb #ad #ag #ab #adaf ,nor!rn ,zone ( ,asia #d #f #f #d #d #c #e #g #f #c #d #e #dg #ahgf-ahha1 ,japan 7,tokio area7 #ci #da #da #cj #cc #cj #bg #ba #aj #bh #cd #dccad ,japan 7l>ge e>?quakes7 -- #e #c #c #a -- #e #d -- -- #a #e #b ,alg]ia & ,nor?'rn ,africa #e #b #f #g #c #b #b #e #a #d #h #a #ch ,unit$ ,/ates & ,canada #d #d #c #c #c -- #d #f #c #b #g #e #ch ,java1 ,sumatra1 c41 #ahgc-d-e-g & #i #ce #cj #ch #cc #bb #cf #bg #dj #bd #ce #cj #bfca ,mexico & ,c5tral ,am]ica #c #b #b #b #f #b #b #a #a #c #b #c #be ,antilles #i #h #ai #ab #ab #aj #i #af #ab #aj #ac #abaah ,cuba #d #c #b #c #c #d #e #b #f #e #f #d #d ,*ili & ,la ,plata #ad #aj #ad #h #ai #aa #af #ae #af #i #bg #haci ,p]u1 ,columbia1 ,bas9s ( ,amazons1 xvi-xix #ib #hc #ib #bgajf #gi #id #ic #ig #gg #gb #ijhg ,new ,zeal&1 #ahfi-gi #ca #bg #cg #bc #bb #ca #bg #cf #cg #ba #bg #bcbhe ,jan4 #ahej1 ,dec4 #aheg ,nor!rn ,hemisph]e #aecafbadcafaabfabdadaaefaedagaaeaafhaej ,s\!rn ,hemisph]e #ge #dc #fa #ff #df #db #ec #ci #ed #ee #eg #dfec #ahba-ahcj ,nor!rn ,hemisph]e #ca #cf #ca #bi #cc #cc #bj #ca #bd #da #bf #cdcj ,s\!rn ,hemisph]e #b -- #a #a #c #a #c #b #c #b #a #a #af ---------------------------------------- ------------------------- ,a glance at ?is table %[s t = mo/ c\ntries 9 ! nor!rn hemisph]e ! rule t !re are g5]ally m e>?quakes dur+ ! w9t] mon?s--t is1 f ,octob] to ,m>*--holds good4 ,= c\ntries :i* lie comp>atively ne> to ! ,equator1 & also = ^? c\ntries 9 ! s\!rn hemisph]e1 ! rule is n s cle>4 ,:5 exam9+ ?is table x mu/ be rememb]$ t x does n enable u to judge ( ! relative frequ5cy ( e>?quakes 9 diff]5t c\ntries1 inasmu* z ! p]iods ov] :i* ! records 7 tak5 are diff]5t 9 diff]5t cases4 ,to ! above table might be add$ ! records ( ,p4 ,m]ian1 :o exam9$ ! e>?quakes felt 9 ,basle up to #ahca4 ,z a result he f\nd t dur+ ! w9t] mon?s eighty %ocks _h be5 felt1 :il/ dur+ ! summ] only =ty4 ,tak+ ! records = ! two hemisph]es f #ahej-aheg1 compil$ by ,kluge1#ajb 9 ! nor!rn hemisph]e we h 9 ! mon?s betwe5 ,octob] & ,m>* #idh %ocks aga9/ #hfb 9 ! rema9d] ( ! ye>4 ,9 ! same mon?s 9 ! s\!rn hemisph]e we h = ! correspond+ p]iods ! numb]s #ccg & #cjj1 & ?us bo? hemisph]es w\ld appe> to foll[ ! same rule4 ,if1 h[ev]1 we exam9e ! table we see t ! two seasons are n s pron\nc$ = ! s\!rn hemisph]e z !y are = ! nor!rn1 & t !re may be two or ?ree p]iods ( maximum di/urbance z has be5 previ\sly indicat$4 ,e>?quakes & ! planets & meteors4--,j z ! moon & ! sun may ex]t an attractive influ5ce ^u ! e>? & cause e>?quakes to pr$om9ate at c]ta9 seasons r ?an at o!rs1 sev]al inve/igators ( seismic ph5om5a h ?\ght t ! planets might act 9 a simil> mann]4 ,m4 ,j4 ,delauney1 f a /udy ( ,p]rey's tables ( e>?quakes f #agej-ahdb1 f\nd two gr\ps ( maxima ea* ) a p]iod ( ab\t twelve ye>s1 "o comm5c+ 9 #agei & ! o!r 9 #agef4 ,two o!r gr\ps ) tw5ty-eight ye> p]iods respectively comm5ce 9 #agef & #aggc4 ,^! gr\ps co9cide ) ! times :5 ,jupit] & ,saturn rea* ! mean longitudes ( #bfe & #ace4 ,f ?is ,delauney concludes t e>?quakes h a maximum :5 ! planets are 9 ! mean longitudes j m5tion$4 ,! increas$ numb] ( e>?quakes1 especially 9 ,novemb]1 are attribut$ to ! passage ( ! e>? ?r\gh sw>ms ( meteors1 & 9 l mann] supposes ! influ5ce ( ,jupit] & ,saturn to be due to _! pass+ ?r\gh meteor /reams situat$ 9 mean longitudes #ace & #bfe4 ,z a consequ5ce ( ?is he pr$icts an increase ( e>?quakes 9 ! ye>s #ahhf1 #ahia1 #ahih1 #aijj1 c4#ajc ,dr4 ,e4 ,naumann1 :o critically exam9$ ! l>ge e>?quakes ( ,japan1 %[$ t !re 0 an approximate co9cid5ce betwe5 _m ( ! di/urbances & ! ?irty-?ree ye> p]iod ( meteoric %[]s4#ajd ,humboldt /ates t a great %[] ( meteors 0 se5 at ,quito be=e ! great e>?quake ( ,riobamba 7,feb4 #d1 #agig74 ,! e>?quakes ( #agff & #agii at ,cumana are also said to h be5 accompani$ ) meteoric %[]s4 ,mallet gives a li/ ( l>ge e>?quakes :i* occurr$ at ! times :5 meteors 7 obs]v$4#aje ,! h\rs at :i* e>?quakes are mo/ frequ5t4--,f ! exam9ation ( a catalogue ( ov] #b1jjj e>?quakes :i* occurr$ 9 v>i\s p>ts ( ! _w betwe5 ! ye>s #ahej & #aheg1 made by ,kluge1 x is f\nd t bo? = ! nor!rn & s\!rn hemisph]es ! obs]vations :i* 7 made dur+ ! night g5]ally exce$ ^? :i* 7 made dur+ ! day4 ---------------------------------------- ---------- ,numb] ( ,e>?quakes ---------------------------------------- ---------- ,day ,night ,9 ! ,nor!rn ,hemisph]e #ich #aeib ,9 ! ,s\!rn ,hemisph]e #bib #ceg ---------------------------------------- --------- ,9 ! nor!rn hemisph]e ! greate/ numb] 7 obs]v$ betwe5 #aj ,p4,m4 & #ab ,p4,m4 7#cfj %ocks71 & ! fewe/ betwe5 #ab & #b ,p4,m4 7#aci %ocks74 ,9 ! s\!rn hemisph]e1 ! greate/ numb] 7 obs]v$ at night betwe5 #ab & #a1 & ! smalle/ numb] betwe5 #a & #b & #d & #e 9 ! aft]noon4#ajf ,^! di/9ctions1 h[ev]1 are less di/9ctly m>k$ z we approa* ! ,equator4 ,s*midt f\nd = ! e>?quakes ( ! ,ori5t betwe5 #aggd & #ahgc1 t %ocks _h be5 mo/ frequ5t ab\t half-pa/ two ,a4,m41 & less frequ5t ab\t #a ,p4,m4 ,) reg>d to ^! conclusions1 :i* h be5 rea*$ ) mu* lab\r1 we might be incl9$ to ?9k t !y are p>tially to be expla9$ on ! supposition t m obs]vations are made dur+ ! night ?an dur+ ! day--! p]sonal exp]i5ce ( resid5ts 9 an e>?quake c\ntry be+1 t _m e>?quakes :i* occur dur+ ! day are pass$ by unnotic$1 :il/ ^? :i* occur dur+ ! night are record$ by ?\s&s ( obs]v]s4 ,su* a view is c]ta9ly confirm$ by ! in/rum5tal records obta9$ 9 ,japan4 ,f #ahgb to #ahhj inclusive !re 7 #bfa %ocks record$1 #acb ( :i* occurr$ betwe5 ! h\rs ( #f ,p4,m4 & #f ,a4,m4 ,e>?quakes & sun spots4--,( late ye>s consid]able att5tion has be5 drawn to a co9cid5ce betwe5 ! occurr5ce ( sun spots1 magnetic di/urbances1 ra9fall1 & o!r natural ph5om5a4 ,^! p]iods ( sun spots occur ab\t e elev5 ye>s1 & appe> to be co9cid5t ) ! p]iodical return ( ! planet ,jupit]4 ,9 ,japan1 ,dr4 ,e4 ,naumann s\ght = a co9cid5ce betwe5 ^! p]iods ( sun spots & e>?quakes1 b )\t any m>k$ results4 ,s*midt1 :o c>efully comp>$ 8 li/s ( e>?quakes ) ! appe>ance ( sun spots1 came to ! conclusion t !re 0 no m>k$ co9cid5ce4 ,! occurr5ce ( e>?quakes _h sometimes syn*ronis$ ) sun spots1 :il/ at o!r times !re _h be5 a maximum ( sun spots & no e>?quakes4 ,m4 ,r4 ,wolf#ajg app>5tly consid]s t e>?quakes1 l volcanic eruptions & ! appe>ance ( ! aurora1 are co9cid5t ) sun spots4 ,kluge1 h[ev]1 came to ! conclusion t :5 !re are few sun spots1 e>?quakes1 l volcanic eruptions & magnetic di/urbances1 h be5 at a maximum4 ,m4 ,a4 ,poey1 :o exam9$ a catalogue ( ! e>?quakes ( ,mexico & ! ,antilles1 ext5d+ f #afcd to #ahgj1 %[s by a table t e>?quakes h come 9 gr\ps1 fir/ at ! maxima & !n at ! m9ima p]iod ( sun spots4 ,out ( ?irty-eight gr\ps1 sev5te5 be+ at ! maximum & sev5te5 at ! m9imum1 ! rema9+ f\r are exceptions to ! rule1 be+ betwe5 ! maximum & m9imum4 ,ph5om5a :i* are dep5d5t ^u heat occur ) ! m9ima ( sun spots1 & ^? dep5d5t ^u cold ) ! maxima4#ajh ,e>?quakes & ! aurora4--,! possible connection betwe5 e>?quakes & ! aurora is a subject :i* has attract$ "s att5tion4 ,b\ has especially made a c>eful exam9ation ( ?is subject4#aji ,he comes to ! conclusion t if we comp>e ! mon?ly p]iods ( e>?quake frequ5cy & ! aurora !re is an agreem5t betwe5 ! two4 ,comp>+ ,p]rey's tables ( e>?quakes f ! f\r? to ! n9ete5? c5tury1 ) tables ( ! aurora1 "o-?ird ( bo? ph5om5a h occurr$1 n only 9 ! same day1 b (t5 at ! same h\r4 ,betwe5 #ahcd & #ahdg1 #deg e>?quakes are giv5 & #cea notices ( ! aurora4 ,out ( ^!3-- #dh occur on ! same day1 #e occur 9 ! same h\r1 #cj approximate to ! same "t4 ,! ne>] toge!r t ^! ph5om5a h occurr$ ! /rong] h !y be54 ,pr(essor ,m4 ,s4 di ,rossi br+s =w>d _m examples :]e !re has be5 a co9cid5ce betwe5 ! appe>ance ( ! aurora & e>?quakes4 ,on #aci nights out ( #baa days ! aurora 0 se5 9 "s p>ts ( ,italy1 & n9ety-?ree times e>?quakes 7 felt4 ,on =ty-six occasions e>?quakes & aurora took place toge!r4#aaj ,9 consid]+ ! probability ( a connection exi/+ betwe5 ^! two ph5om5a1 we mu/ be> 9 m9d t ! aurora is at no great height above ! surface ( our e>?1 &1 fur!r1 t x c be p>tially imitat$4 ,! fact t 9 e>?quake c\ntries1 l ,japan1 ! aurora is practically nev] se51 w\ld indicate t we c nei!r reg>d ?is imp]fectly und]/ood ph5om5on ei!r z an effect or cause ( e>?quakes4 ,t e>?quakes & ! appe>ance ( ! aurora 9 c]ta9 c\ntries %\ld n sometimes co9cide is an impossibility4 ,dr4 ,/ukeley1 :o1 x mu/ be rememb]$1 attempt$ to correlate ! ph5om5a ( e>?quakes & electricity1 :5 writ+ ( ! di/urbances :i* %ook ,engl& 9 #ahdi & #ahej1 says t ! wea!r _h be5 unusually w>m1 ! aurora borealis frequ5t & ( unusually bright col\rs1 :il/ ! :ole ye> 0 rem>kable = its fire-balls1 lightn+s1 & corruscations4#aaa ,! aurora 0 obs]v$ be=e ! comm5cem5t ( ! ,mae/ri*t e>?quakes 9 #ageaaab2 :il/ at ! "t ( ! %ock fla%es ( light l lightn+ 7 obs]v$ 9 ! sky4 ,glimm]+ lights 7 se5 9 ! sky be=e ! ,new ,engl& e>?quakes 7,nov4 #ah1 #agee71 & aga91 be=e ! di/urbances :i* occurr$ 9 ! same region 9 #agbg1 peculi> fla%es ( light 7 se54 ,prec$+ ! ,sicilian e>?quake ( #afib /range lights 7 se5 9 ! sky4 ,ignis fatui h also be5 obs]v$ ) e>?quakes4 ,at ! "t ( auroral displays ,b]telli has obs]v$ microseismical di/urbances1 & ,m4 ,s4 di ,rossi1 :o has made simil> obs]vations1 ?9ks t !re is an intimate connection betwe5 ! aurora & e>?quakes2 ! aurora ei!r occurr+ 9 a p]iod ( e>?quakes1 or else tak+ ! place ( e>?quakes4 ,,*apt] ,,xv4 ,,b>ometrical ,,fluctuations ,,& ,,e>?quakes--,,fluctuations ,,9 ,,temp]ature ,,& ,,e>?quakes4 ,*anges 9 ! b>omet] & e>?quakes4--,mallet1 :o collect$ toge!r a numb] ( examples ( e>?quakes :i* h occurr$ ) a fall ( ! b>omet]1 & a numb] :i* h happ5$ ) a rise1 concludes t !re are z _m in/ances ( ! "o z ( ! o!r4 ,at ! great e>?quake ( ,calabria1 9 #aghc1 ! b>omet] 0 v l[4 ,! e>?quake ( ! ,rh9e 7,febru>y #bc1 #ahbh7 0 prec$$ by a gradual fall ( ! b>omet]1 :i* rea*$ its l[e/ po9t ^u t day4 ,aft] ! e>?quake ! b>omet] aga9 rose4 ,! e>?quake ( ,febru>y #bb1 #ahhj1 9 ,japan1 0 accompani$ by exactly simil> ph5om5a4 ,caldcleugh1 :o obs]v$ ! heavy %ocks 9 ,*ili 7,febru>y #bj1 #ahce71 notic$ t on ,febru>y #ag & #ah ! b>omet] fell #e_/aj in*es4 ,simil> ph5om5a 7 obs]v$ be=e ! succe$+ small] %ocks4 ,aft] ! %ocks ! b>omet] aga9 rose4 ,pr9cipal ,dawson1 speak+ ( ! e>?quakes ( ,canada1 obs]ves t "s ( ! %ocks h be5 accompani$ ) a l[ b>omet]4 ,p4 ,m]ian1 :o exam9$ ! connection betwe5 ! ,swiss e>?quakes & atmosph]ic pressure1 f\nd t out ( tw5ty-two e>?quakes obs]v$ 9 ,basle betwe5 #agee & #ahcf1 ?irte5 ( ^! 7 local %ocks1 ( :i* eight 7 accompani$ ) sudd5 *anges ( pressure4 ,( ! rema9+ n9e1 :i* 7 only felt slightly 9 ,basle1 no *ange 9 atmosph]ic pressure 0 obs]v$4 ,( ?irty-six e>?quakes :i*1 betwe5 #ahbf & #ahcf1 7 felt 9 ,switz]l&1 ?irty 7 *iefly conf9$ to ,switz]l&1 & t5 ( ^! occurr$ ) a l[ or fall+ b>omet]4 ,humboldt is ( op9ion t e>?quakes only occur ) *anges 9 b>ometric pressure 9 ^? c\ntries :]e e>?quakes are few2 & he gives examples :]e ! regul> v>iations ( ! b>omet] h gone on )\t int]ruption at ! "t ( e>?quakes4 ,fr$]ick ,h(fmann1 :o exam9$ fifty-sev5 e>?quakes :i* occurr$ at ,pal]mo betwe5 #aghh & #ahch1 came to ! foll[+ result3-- ,! b>omet] 0 s9k+ 9 #bj cases ris+ 9 #af at a m9imum 9 #g maximum 9 #c undet]m9$ 9 #aa #aac ,! obs]vations ( ,m4 ,s4 di ,rossi app>5tly %[ t ! e>?quakes 9 ,italy *iefly occur ) a b>ometrical depression & ) sudd5 jumps 9 atmosph]ic pressure4 ,s*midt1 :o exam9$ ! e>?quakes ( ! ,ori5t1 :i* occurr$ betwe5 #aheh & #ahgc1 says t !y 7 r>e ) a high b>omet]1 b num]\s :5 ! b>omet] 0 l[4 ,f an exam9ation ( a table ( #cif e>?quakes 7,may #h1 #ahge-;,dec4 #ahha7 felt 9 ,tokio1 furni%$ to me by ,mr4 ,arai ,ikunosuke1 ! director ( ! meteorological dep>tm5t1 ,i obta9$ ! foll[+ results3-- ,! b>omet] 0 ris+ 9 #afi cases fall+ 9 #aed /eady 9 #gc bel[ ! mon?ly mean 9 #ahi above 9 #aib ,f ?is x w\ld appe> t 9 ,japan at lea/ ! movem5ts ( ! b>omet] d n %[ any m>k$ connection ) ! occurr5ce ( e>?quakes4 ,:5 consid]+ ?is "q we mu/ rememb] ! m>k$ effects :i* a l[]+ ( ! b>omet] produces ^u c]ta9 volcanoes & solfat>as4 ,! volumes ( /eam emitt$ f ,/romboli & f "s ( ! solfat>as 9 ,tuscany hold a m>k$ connection ) atmosph]ic pressure z ! quantity ( fire damp giv5 (f f coal seams--^! be+ greate/ :5 ! b>omet] is l[4 ,at c]ta9 *anges ( ! wea!r x is said t ! volcano ( ,vulture1 ne> ,melfi1 emits noises4 ,^! ph5om5a at once place volcanic ph5om5a & b>ometrical pressure 9 direct relation%ip4 ,*anges 9 temp]ature4--,if1 ) an e>?quake1 x %\ld happ5 t !re is a *ange 9 ! height ( ! b>omet]1 we %\ld naturally expect t ?is might be accompani$ ) ! *anges 9 ! temp]ature1 9 ! w9d1 & 9 o!r atmosph]ic ph5om5a :i* are m or less connect$ ) ! height ( ! b>omet]4 ,_m times x has be5 obs]v$ t aft] an e>?quake !re has be5 a sudd5 fall 9 ! temp]ature4 ,su* 0 ! case ) ! ,yokohama e>?quakes ( #ahhj4 ,cotte endeav\rs to %[ t ! e>?quakes ( ,lisbon produc$ a *ange ^u ! temp]ature ( all ,europe4 ,9 ! ye> :i* foll[$ ?is e>?quake /orms 7 m common ?an usual4 ,kluge has collect$ toge!r a l>ge numb] ( examples :5 !re has be5 a fall ( temp]ature at ! "t ( an e>?quake4#aad ,at ,kia*ta1 9 ,sib]ia1 at ! "t ( ! e>?quake ( ,decemb] #bg1 #ahef1 ! !rmomet] fell f #ab to #be ,r4 ,we mu/1 h[ev]1 rememb] t !re are _m cases kn[n :]e ! !rmomet] rose4 ,m4 ,s4 di ,rossi rem>ks t we h ! highe/ records ( temp]ature 9 ! ye>s ri*e/ 9 e>?quakes4 ,?us1 9 #ahgc1 at ! "t ( ! e>?quakes 9 ,c5tral & ,nor!rn ,italy1 an abnormal high temp]ature 0 rem>k$4 ,japanese writ]s h rem>k$ ^u ! unusual heat :i* has %ak5 _! c\ntries4 ,! temp]ature ( subt]ranean wat]s h be5 kn[n to increase be=e e>?quakes4 ,,*apt] ,,xvi4 ,,relation ,,( ,,seismic ,,to ,,volcanic ,,ph5om5a4 ,want ( syn*ronism betwe5 e>?quakes & volcanic eruptions--,syn*ronism betwe5 e>?quakes & volcanic eruptions--,conclusion4 ,connection betwe5 e>?quakes & volcanic eruptions4--,insomu* z x is a recognis$ fact t regions :i* are *>act]is$ by _! seismic activity are *iefly ^? :i* are also *>act]is$ by ! numb] ( _! volcanoes1 x is g5]ally assum$ t ^! two ph5om5a h an intimate relation4 ,! resid5ts 9 a volcanic c\ntry1 :5 seek+ = ! orig9 ( an e>?quake1 inv>iably turn t[>ds ! volcanoes :i* surr\nd !m4 ,if a neighb\r+ volcano is 9 a /ate ( activity1 x is (t5 reg>d$ z a safegu>d aga9/ seismic convulsions1 9 o!r cases x is look$ ^u z be+ ! cause ( su* di/urbances4 ,9 c]ta9 in/ances bo? ( ^! views h app>5tly be5 corroborat$4 ,:5 we consid] t an e>?quake & a volcanic eruption may bo? be ! result ( "s great int]nal convulsion1 & t fir/ "o & !n ! o!r may take place 9 ! same neighb\rhood1 x is natural to expect t :5 ^! int]nal =ces h exp5d$ !mselves 9 ! production ( "o ( ^! ph5om5a1 x is n s likely t !y %\ld exhibit !mselves 9 ! o!r4 ,! inhabitants ( ,sicily & ,naples1 we are told1 reg>d eruptions ( ,etna & ,vesuvius z safegu>ds aga9/ e>?quakes4 ,a simil> belief is to be f\nd 9 portions ( ,s\? ,am]ica ) reg>d to ! volcanoes = :i* t c\ntry is s celebrat$4 ,f an exam9ation ( ! records ( ! l>ge e>?quakes & ! volcanic eruptions :i* h tak5 place 9 ,japan dur+ ! la/ #b1jjj ye>s1 ,dr4 ,naumann f\nd t !re 0 (t5 an approximate co9cid5ce betwe5 ! times ( ! occurr5ce ( ^! ph5om5a1 sugge/+ ! idea t ! ef=ts :i* _h be5 suffici5t to e/abli% ! volcano _h at ! same "t be5 suffici5t to %ake ! gr\nd4 ,( de/ructive e>?quakes :i* h occurr$ at ! "t ( volcanic eruptions1 & ( examples :5 ^! ph5om5a h occurr$ at widely sep>at$ int]vals1 ! records are extremely num]\s4 ,want ( syn*ronism betwe5 e>?quakes & volcanic eruptions4--,_m ( ! great e>?quakes ( ,s\? ,am]ica d n appe> to h be5 connect$ ) volcanic eruptions4 ,! great e>?quakes ( ! _w1 l ^? ( ,calabria & ,lisbon1 :i* took place 9 regions :i* are n volcanic1 h n1 ,fu*s tells u1 tak5 place 9 conjunction ) volcanic outbur/s4 ,9 ,japan1 z 9 ! ,s&wi* ,isl&s & 9 _m o!r p>ts ( ! globe1 ! small e>?quakes :i* occur almo/ daily d n appe> to %[ any m>k$ connection ) volcanic di/urbances4 ,9 #ahha1 dur+ ! eruption ( ,natu/ake1 a volcano ly+ ab\t a hundr$ miles nor? ( ,tokio1 !re 0 nei!r an increase nor a decrease 9 ! e>?quakes :i* 7 felt 9 ,tokio4 ,simil> rem>ks apply to ! /ate ( seismic activity ( #ahgf-gg1 :5 ,o%ima1 a volcanic isl& ab\t sev5ty miles to ! s\? ( ,tokio1 0 9 eruption4 ,9 ! ,s&wi* ,isl&s ,mauna ,loa seems to h its eruptions indep5d5tly ( ! di/urbances :i* %ake ^! isl&s4#aae ,syn*ronism ( e>?quakes & volcanic eruptions4--,al?\gh _m examples l ! above may be quot$1 :i* app>5tly %[ an utt] want ( connection betwe5 e>?quakes & volcanoes1 we mu/ n ov]look t class ( e>?quakes :i* almo/ inv>iably accompany all great volcanic di/urbances4 ,9 fact ! sudd5 explosions :i* take place at volcanic foci1 z1 = in/ance1 at ! comm5cem5t ( an eruption1 are enum]at$ z "o ( ! causes :i* produce e>?quakes4 ,e>?quakes l ^! usually cont9ue until ! pressure ( ! /eam & lava h f\nd = !mselves an op5+4 ,z comp>$ ) ! total numb] ( e>?quakes :i* are record$1 !y =m b an insignificant portion4 ,! direct connection :i* exi/s betwe5 ^! ph5om5a has1 no d\bt1 done v mu* to spread ! popul> belief t all e>?quakes may be connect$ ) volcanic eruptions4 ,z examples :]e ?is connection has exi/$ we might quote f almo/ all ! volcanic c\ntries 9 ! _w4 ,?us1 ,fu*s tells u t on ,octob] #f1 #agcg1 almo/ ! :ole ( ,kams*atka & ! ,kurile ,isl&s 7 di/urb$ by movem5ts :i* 7 simultane\s ) ! outbreak ( ! great volcano ,kluts*5skja ( ,nor? ,kams*atka4 ,"o ( ! e>lie/ records ( a sev]e e>?quake & a volcanic eruption occurr+ simultane\sly is f\nd 9 ! acc\nts ( ! de/ruction ( ,h]culaneum & ,pompeii4 ,! ?r[+ up ( ,monte ,nuovo 9 ! neighb\rhood ( ,pozzuoli 0 accompani$ ) a dreadful e>?quake4#aaf ,9 #ahfh ! e>?quake ( ,arequipa 0 accompani$ by ! op5+ ( ! volcano ,mi/i1 on its nor? side4 ,! di/ance to ! volcano is ab\t f\rte5 miles4 ,at ! "t ( ! eruptions ( ,kilauea 9 #aghi ! gr\nd %ook & rock$ s t p]sons c\ld n /&4 ,! fir/ eruption ( ! volcano ,irasu1 9 ,co/a ,rica 7#aghc71 0 accompani$ by viol5t e>?quakes4#aag ,! smoke & flames :i* are said to h issu$ f ! side ( ,m\nt ,fojo at ! "t ( ! ,lisbon e>?quake are reg>d$ by "s z hav+ be5 volcanic4 ,o!rs ?\ght t ! ph5om5a1 r ?an be+ on ! side ( ,fojo1 :i* %[$ no traces ( volcanic action1 _h tak5 place 9 ! ocean4 ,at ! "t ( ! great e>?quake at ,concepcion 7#ahce71 :il/ ! waves 7 com+ 91 two great subm>9e eruptions 7 obs]v$4 ,"o1 beh9d ! ,isle ( ,quiriqu9a1 appe>$ l a column ( smoke4 ,! o!r1 9 ! bay ( ,san ,vic5te1 appe>$ to =m a :irlpool4 ,! sea-wat] became black1 & _h a sulphur\s smell1 !re be+ a va/ eruption ( gas 9 bubbles4 ,_m fi% 7 kill$4#aah ,) ?is same e>?quake1 ne> to ,juan ,f]n&ez1 ab\t "o mile f ! %ore1 ! sea appe>$ to boil1 & a high column ( smoke 0 ?r[n into ! air4 ,at night flames 7 se54 ,9 #ahfa1 :5 ,m5doza 0 de/roy$ & #aj1jjj inhabitants kill$1 a volcano at ! foot ( :i* ,m5doza is situat$ bur/ into eruption4 ,! e>?quake ( #ahbb at ,valdivia 0 accompani$ by eruptions ( ! neighb\r+ m\nta9s1 :i* only la/$ a few m9utes4 ,at ! "t ( ! ,leghorn %ocks 7,janu>y #af-bg1 #agdb7 "s fi%]m5 obs]v$ a "p ( ! sea to rage viol5tly1 to raise itself to a great height1 & !n ru% l&w>ds4#aai ,9 #agig1 :5 ,riobamba 0 de/roy$1 ! neighb\r+ volcanoes 7 n affect$1 b ,m\nt ,pa/o1 #abj miles di/ant1 sudd5ly ceas$ to ?r[ out its usual column ( wat]4 ,on ! night ( ,decemb] #aj1 #ahgd1 a /rong %ock 0 felt 9 ,new ,engl&1 :il/ at #d4de ,a4,m4 on ,decemb] #aa a %ock 0 felt 9 ! ,pic du ,midi1 9 ! ,pyr5ees4 ,9 ! middle ( ,decemb] !re 7 volcanic outbur/s 9 ,icel&4#abj ,x is possible t ^! occurr5ces might be ! results ( "s widespread di/urbance b5ea? ! cru/ ( ! e>?1 or p]haps ev5 ( widely ext5d$ e>? pulsations4 ,! probability1 h[ev]1 is t ^! co9cid5ces are accid5tal4 ,:5 we rememb] t 9 a small area l ! nor!rn half ( ,japan alone !re are p]iods :5 !re are at lea/ two %ocks p] day on ! av]age1 x is impossible = ^! co9cid5ces n to exi/4 ,less frequ5tly co9cid5ces betwe5 ! l>g] di/urbances mu/ occur4 ,ov] & above ^! accid5tal co9cid5ces1 x w\ld appe> t 9 ! _w's hi/ory p]iods h occurr$ :5 e>?quakes 7 unusually frequ5t1 & at su* times di/ant c\ntries h suff]$ simultane\sly4 ,?is approximate co9cid5ce 9 p]iod1 :i* has be5 ref]r$ to :5 speak+ ( ! di/ribution ( de/ructive e>?quakes 9 hi/orical "t1 does n imply an exact syn*ronism 9 ! s+le %ocks4 ,small e>?quakes1 or1 m prop]ly speak+1 local trembl+s1 are a necess>y accompanim5t ( almo/ all volcanic eruptions4 ,tremors ( ?is description are seldom1 h[ev]1 felt beyond ! crat]1 or at ! mo/ ^u ! flanks ( ! m\nta9 :]e ! eruption is go+ on4 ,!y are due to ! explosive action ( /eam bur/+ ?r\gh ! molt5 lava4 ,volcanic eruption succe$+ e>?quakes4--,sometimes x has happ5$ t an e>?quake1 or a s]ies ( e>?quakes1 h t]m9at$ ) ! =mation ( volcanic v5ts4 ,z an example ( a volcanic outbur/ t]m9at+ a seismic di/urbance1 may be m5tion$ ! appe>ance ( a new volcano 9 ! c5tre ( ,lake ,ilopango1 z a sequel to ! %ocks :i* _h di/urb$ t neighb\rhood 9 #ahgi4aba ,9 #agej !re 7 cont9u\s %ak+s la/+ ov] ?ree mon?s at ,manilla4 ,^! t]m9at$ ) an eruption ( a small isl& 9 ! middle ( a neighb\r+ lake4 ,?ree days aft] ! comm5cem5t ( ?is eruption1 f\r o!r small isl&s rose 9 ! same lake4#abb ,antonio d',ulloa1 :5 speak+ ( ! ,&es1 rem>ks t aft] a volcanic eruption ! %ocks cease4#abc ,conclusion4--,look+ at ?is "q g5]ally1 insomu* z ! greate/ numb] ( volcanic eruptions appe>1 accord+ to ,fu*s1 to h tak5 place 9 summ]1 :il/ ! greate/ numb] ( its e>?quakes h app>5tly tak5 place 9 w9t]1 x w\ld seem t ! two ph5om5a are )\t any direct connection1 unless x be t bo? are diff]5t effects ( a common cause4 ,reg>d$ 9 ?is mann]1 an e>?quake may be look$ ^u z an uncomplet$ ef=t to e/abli% a volcano4 ,to use ! words ( ,mallet1 #8,! =ces ( explosion & impulse are ! same 9 bo?2 !y diff] only 9 degree ( en]gy1 or on ! v>y+ sorts & degrees ( resi/ance oppos$ to !m4'#abd ,al?\gh we h _m examples ( e>?quakes hav+ occurr$ )\t volcanic eruptions1 &1 on ! o!r h&1 ( volcanic eruptions )\t e>?quakes1 volcanoes may /ill be reg>d$ z #8safety-valves ( ! e>?'s cru/1' :i*1 by giv+ relief to int]nal /resses1 gu>d u aga9/ ! effects ( e>?quakes4 ,t _m e>?quakes are felt at ,copiapo is attribut$ to ! fact t 9 ! neighb\r+ m\nta9s !re are no volcanic v5ts4 ,we mu/ n1 h[ev]1 ov]rate ! protective influ5ce ( volcanoes4 ,9 ! ,s&wi* ,isl&s we see ! columns ( liquid lava 9 neighb\r+ m\nta9s /&+ at diff]5t heights1 indicat+ a want ( subt]ranean connection betwe5 ^! v5ts4 ,9 consequ5ce ( ?is x w\ld seem t enorm\s pressures might be g5]at$ 9 ! neighb\rhood ( "o ( ^! m\nta9s )\t f9d+ relief at ! o!r4 ,:5 we h conditions l ^!1 x w\ld seem t ! eruption ( a volcano may h little or no influ5ce 9 protect+ neighb\r+ di/ricts4 ,?is may possibly be ! explanation ( ! fact t 9 #ahce ,concepcion 0 de/roy$1 not)/&+ !re be+ an unusual activity 9 ! volcanic v5ts ( ! neighb\r+ m\nta9s4 ,,*apt] ,,xvii4 ,,! ,,cause ,,( ,,e>?quakes4 ,mod]n views respect+ ! cause ( e>?quakes--,e>?quakes due to fault+--,to explosions ( /eam--,to volcanic evisc]ation--,to *emical degradation--,attractive influ5ce ( ! heav5ly bodies--,! effect ( oceanic tides--,v>iation 9 atmosph]ic pressure--,fluctuation 9 temp]ature--,w9ds & e>?quakes--,ra9 & e>?quakes--,conclusion4 ,z ! results ( mod]n inquiries respect+ ! cause ( e>?quakes1 we see _m inve/igators *iefly attribut+ ^! ph5om5a to special causes4 ,a few attribute !m to sev]al causes4 ,x seems to u t !y might be attribut$ to v _m causes :i* (t5 act 9 a complex mann]4 ,! prim>y causes are telluric heats1 sol> heat1 & v>iations 9 gravitat+ influ5ces4 ,^! may be ! pr9cipal1 & sometimes ! imm$iate1 cause ( an e>?quake4 ,! second>y causes are ^? dep5d5t ^u ! prim>y causes1 su* z expansions & contractions ( ! e>?'s cru/1 v>iations 9 temp]ature1 b>ometrical pressure1 ra91 w9d1 ! attractive influ5ces ( ! sun & moon 9 produc+ tides 9 ! ocean or ! e>?'s cru/1 v>iations 9 ! di/ribution ( /ress ^u ! e>?'s surface caus$ by processes ( degradation1 ! alt]ations 9 ! position ( isogeo!rmal surfaces1 c4 ,! "p :i* may be play$ by ^! v>i\s causes 9 ! production ( oscillations1 pulsations1 & tremors w be ref]r$ to4 ,e>?quakes consequ5t on fault+4--,9 ! *apt] on ,e>? ,oscillations1 ! causes produc+ ! ph5om5a ( elevation & depression are briefly indicat$4 ,by ! v>iations 9 /ress accompany+ elevations & depressions1 cracks are produc$4 ,inasmu* z compression w\ld cru% ! rocks con/itut+ ! e>?'s cru/1 we mu/ conclude ) ,capta9 ,dutton t ^! cracks are =m$ by t5sion4 ,by elevation1 ! upp] rigid cru/ ( ! e>? is /ret*$1 & fissures are produc$4 ,! sudd5 =mation ( ^! fissures or faults gives rise to e>?quakes1 & p]haps also to volcanic v5ts4 ,t e>?quake & volcanic regions are situat$ on areas :]e !re is evid5ce ( rapid elevation is /rik+ly illu/rat$ r\nd ! %ores ( ! ,pacific4 ,lasaulx consid]$ t ! e>?quake ( ,h]zog5ra? 0 m or less intimately connect$ ) ! great m\nta9 fissure--! ,feldbiss--:i* crosses ! coal region ( ! ,wurm4#abe ,! sudd5 elevation or s9k+ ( l>ge areas at ! "t ( an e>?quake may be a consequ5ce ( ^! dislocations4 ,x has already be5 po9t$ out t ! e>?quake region ( ,japan is ! "o :]e we h evid5ce ( rec5t & rapid elevation4 ,t c]ta9 e>?quakes ( ?is region may possibly be ! result ( fault+ we h ! evid5ce ( our s5ses & ( our in/rum5ts4 ,! sudd5 bl[s & jolts :i* are sometimes felt are indicative ( ! slid+ ( "o mass ( rock across ano!r4 ,%\ld ! gr\nd be simply torn asund]1 ?is te>+ w\ld give rise to a s]ies ( waves ( di/ortion1 vibrat+ 9 directions p>allel to ! plane ( ! fissure4 ,suppos+ ?is motion to be propagat$ to a numb] ( surr\nd+ /ations1 x w\ld be record$ at ea* ( ^! z hav+ ! same direction4 ,to ^? situat$ on a l9e =m+ a cont9uation ( ! /rike ( ! fissure1 ! vibrations w\ld advance s to speak end on1 :il/ to ^? /ations ly+ 9 a l9e p]p5dicul> to ! /rike ( ! fissure1 ! motion w\ld advance broadside on4 ,motions l ^! latt] h be5 record$ 9 ,tokio1 :]e e>?quakes :i* f "t obs]vations 7 kn[n to h come f ! fault$ & ris+ region to ! s\? h be5 regi/]$ z a s]ies ( ea/ & we/ motions1 or vibrations transv]se to ?is l9e ( propagation4 ,x mu/1 h[ev]1 be "h m5tion$ t ! regi/ration ( only transv]se motion may possibly be due to ! ext9ction ( normal motion1 al?\gh ?is is n g5]ally reg>d$ z probable4 ,x w\ld !re=e appe> t c]ta9 e>?quakes & faults are closely relat$ ph5om5a1 ! =m] be+ an imm$iate effect ( ! latt]4 ,faults are due to e>? oscillations1 & to a v>iety ( causes produc+ di/urbances 9 ! equilibrium ( ! e>?'s cru/2 ! pr9cipal cause ( all ^! ph5om5a be+ alt]ations 9 ! di/ribution ( heat1 & ! attractive =ce ( gravity4 ,e>?quakes consequ5t on ! explosion ( /eam4--,humboldt reg>d$ volcanoes & e>?quakes z ! results ( a common cause1 :i* he =mulat$ z #8! reaction ( ! fi]y int]ior ( ! e>? ^u its rigid cru/4' ,c]ta9 inve/igators1 :o h endeav\r$ to r$uce ,humboldt's explanation to def9ite limits1 h sugge/$ t e>?quakes may be due to sudd5 outbur/s ( /eam b5ea? ! cru/ ( ! e>?1 & its f9al escape ?r\gh cracks & fissures4 ,admitt+ t /eam may accumulate by sep>at+ out f ! cool+ int]ior ( our globe1 its sudd5 explosion might be br\ght ab\t by its own expansive =ce1 or by ! movem5ts 9 ! bubbl+ mass f :i* x orig9at$4 ,o!rs1 h[ev]1 r ?an reg>d ! /eam z be+ a primeval con/itu5t ( ! e>?'s int]ior1 imag9e x arises f ! gradual p]colation ( wat] f ! surface ( ! e>? d[n to volcanic foci1 into :i* x is admitt$ aga9/ oppos+ pressures1 by virtue ( capill>y action4 ,mallet1 9 8 acc\nt ( ! ,neapolitan e>?quake1 %[s t ! :ole ( ! obs]v$ ph5om5a c be acc\nt$ = by ! admission ( /eam into a fissure1 :i* by ! expansive =ce ex]t$ on its walls 0 r5t op54 ,j z at ! ,geys]s we he> ! ?ud & feel ! trembl+ produc$ by ! sudd5 evolution & cond5sation ( /eam1 s may /eam by its sudd5 evolution & cond5sation 9 ! gr\nd b5ea? u give rise to a s]ies ( %ocks ( v>y+ int5sity1 accompani$ by int]m$iate vibratory motions--t is to say1 a motion :i*1 z judg$ ( by our feel+s1 is n unlike _m e>?quakes4 ,(t5 x may happ5 t ! result ( ! explosion may be ! production ( a fault1 or at lea/ a fissure2 & ?us 9 ! result+ movem5ts we may h a v>iety ( vibrations1 "s be+ ^? ( compression & di/ortion1 produc$ by ! bl[ ( ! explosion1 & o!rs be+ ^? ( di/ortion alone1 produc$ by ! %e>+ action :i* may h tak5 place by ! op5+ ( ! fault4 ,sometimes "o set ( ^! vibrations may be prom95t1 & sometimes ! o!r4 ,?us1 :5 we say t an e>?quake has %[n evid5ce by ! nature ( its vibrations t x 0 produc$ by a fault1 ?is by no means precludes ! possibility t an explosion ( /eam may also h be5 connect$ ) ! production ( ! di/urbance4 ,mallet ?rew out ! sugge/ion t ! op5+ ( fissures b5ea? ! ocean might admit wat] to volcanic foci4 ,dur+ ! "t t ! wat] 0 9 ! sph]oidal /ate1 ! prelim9>y tremors1 s common to _m e>?quakes1 w\ld be produc$4 ,^! w\ld be foll[$ by ! explosion1 or s]ies ( explosions1 con/itut+ ! %ock or %ocks ( ! e>?quakes4 ,! *ief reasons = believ+ t ! e>?quakes ( ,nor?-,ea/]n ,japan are p>tly due to explosive ef=ts are3-- #a4 ,t ! great] numb] ( di/urbances1 p]haps n9ety p] c5t41 orig9ate b5ea? ! sea1 :]e we may imag9e t ! gr\nd1 "u ! sup]9cumb5t hydro/atic pressure1 is cont9u\sly be+ saturat$ ) moi/ure4 #b4 ,_m ( ! diagrams %[ t ! prom95t vibrations1 ( :i* !re are usually f "o to ?ree1 9 a giv5 di/urbance h ! same "* z ^? produc$ by an explosive l dynamite1 ! greate/ & probably ! mo/ rapid motions be+ inw>ds t[>ds ! orig94 ,x may "h be rem>k$ t a v l>ge proportion ( ! de/ructive e>?quakes ( ! _w h orig9at$ b5ea? ! sea1 z has (t5 be5 te/ifi$ by ! succe$+ sea waves4 ,also1 x mu/ be obs]v$1 t e>?quake c\ntries1 l volcanic c\ntries1 are *iefly ^? :i* h a coa/ l9e slop+ at a /eep angle b5ea? ! sea--t is to say1 e>?quakes are frequ5t along coa/s bord]$ by deep wat]4 ,! e>?quakes :i* occur at volcanic foci con/itute ano!r class ( di/urbances :i* may be accr$it$ to ! explosive ef=ts ( /eam4 ,e>?quakes due to volcanic evisc]ation4--,by ! ejection ( a%es & lava f volcanic v5ts1 !re is an ext5sive evisc]ation ( ! neighb\r+ gr\nd4 ,:5 we look at a volcano l ,fujiyama1 #ac1jjj feet 9 height1 & at lea/ fifty miles 9 circumf]5ce1 & rememb] t ! mass ( c9d]s & slag ( :i* x is compos$ came f b5ea? ! area on :i* x re/s1 ! po9t to be wond]$ at is1 t e>?quakes1 consequ5t on ! collapse ( subt]ranean holl[s1 are n m frequ5t ?an !y are4 ,at ! "t ( a s+le eruption ( a volcano1 ! quantity ( lava eject$ am\nts to _m ?\s& millions ( cubic feet4 ,9 #aghc ! quantity ( lava eject$ f ,skaptas ,joknee1 9 ,icel&1 0 e/imat$ z surpass+ #89 magnitude ! bulk ( ,mont ,blanc4'#abf ,admitt+ t holl[ spaces are ! results ( ^! eruptions1 & t 9 consequ5ce ( ?is evisc]ation ! gr\nd is r5d]$ un/able1 ! in/ability be+ increas$ by ! additional load plac$ above ! evisc]at$ area1 x w\ld seem t f "t to "t e>?quakes are inevitable4 ,facts1 h[ev]1 tea* u t volcanoes act z safety valves1 & t1 z a rule1 at or %ortly aft] an eruption1 e>?quakes cease4 ,! relation%ip ( e>?quakes to volcanic eruptions w\ld !re=e indicate1 not)/&+ ! argum5ts put =w>d to %[ t an area load$ by a volcano has 9 consequ5ce ( ! evisc]ation & ! load a quaquav]sal dip1 t evisc]ation does n take place b5ea? volcanoes z is usually suppos$1 & we may conclude t x is b few e>?quakes :i* h an orig9 due to ^! causes4 ,e>?quakes & evisc]ation by *emical degradation4--,a p[]ful ag5t1 :i* t5ds to ! =mation ( subt]ranean holl[s1 is *emical degradation4 ,! effects ( ?is h be5 (t5 measur$ by quantitative analysis ( ! solid mat]ials :i* are daily c>ri$ away by _m ( our spr+s4 ,9 lime/one di/ricts ?is is v great4 ,pr(4 ,ramsay e/imates t ! m9]al matt] dis*>g$ annually by ! hot spr+s ( ,ba? is equival5t 9 bulk to a column #adj feet 9 height & #i feet 9 diamet]4 ,at ,san ,filippo1 9 ,tuscany1 ! solid matt] dis*>g$ f ! spr+s has =m$ a hill a mile & a qu>t] long1 a ?ird ( a mile broad1 & #bej feet 9 ?ickness4#abg ,_m o!r examples ( subt]ranean *emical degradation w be f\nd 9 text-books ( geology4 ,by ?is *emical action l>ge cav]n\s holl[s are produc$4 ,b5ea? a volcano x is probable t liquid mat]ial imm$iately takes ! place ( t :i* is eject$1 & t holl[s are n =m$ z 9 ! case ( *emical degradation4 ,if a cav]n becomes too l>ge1 x ev5tually collapses4 ,( ! fall+ 9 ( l>ge excavations we h examples 9 l>ge m9es4 ,z a consequ5ce1 n only is a trembl+ produc$1 b also a noise1 :i* is s l t produc$ by c]ta9 e>?quakes t ! ,s\? ,am]ican m9]s h b "o ^w1 #8bramido1' to express bo?4#abh ,b\ss+ault1 :o 0 an advocate = ! !ory t _m e>?quakes are produc$ by ! s9k+ ( ! gr\nd1 calls att5tion to ! fact t we h evid5ces ( ! subsid5ce ( great m\nta9s1 l ! ,&es1 ! di/ricts ar\nd :i* are s well kn[n = _! e>?quakes4 ,capac ,urcu is "o ( ^! m\nta9s :i* leg5ds tell u has decreas$ 9 height4 ,! v>iation 9 ! height ( m\nta9s is a subject :i* des]ves att5tion4 ,t m\nta9s may possibly be holl[1 we h ! rem>kable results atta9$ by ,capta9 ,h]s*el1 :o f\nd t ! attractive =ce ( gravity 9 ! neighb\rhood ( ! ,himalayas 0 n s great z x ought to h be5 _h ^! m\nta9s be5 solid4 ,! ,rev4 ,o4 ,fi%] gives ano!r explanation ( ?is ph5om5on4 ,palmi]i consid]s t ! t]rible e>?quake :i* deva/at$ ,casamicciola 7#ahha7 0 due to ! hot spr+s hav+ gradually eat5 out cav]n\s spaces b5ea? ! t[n4 ,! extremely local "* ( ?is %ock 0 c]ta9ly fav\rable to su* a view4 ,! e>?quake :i*1 9 #ahdj1 caus$ ,m\nt ,c]nans1 9 ! ,jura1 to fall1 is also attribut$ to ! solv5t action ( wat]s 9 und]m9+ its f\ndations4 ,?is und]m9+ action 0 9 great measure probably due to a l>ge spr+1 :i*1 tw5ty-five ye>s previ\sly1 _h disappe>$1 & :i* subsequ5tly may possibly h be5 sl[ly dis9tegrat+ ! f\ndations ( ! m\nta94 ,e>?quakes ( ?is ord] w\ld be pr9cipally conf9$ to di/ricts :]e !re are rocks :i* are m or less soluble1 z1 = in/ance1 rock salt1 gypsum1 & lime/one4 ,e>?quakes & ! attractive influ5ces ( ! heav5ly bodies4--,! mo/ important attractions ex]cis$ ^u our planet are ^? due to ! sun & moon4 ,to ^! influ5ces we owe ! tides 9 our ocean1 & possibly ela/ic tides 9 ! e>?'s cru/4 ,"s !ori/s w\ld also insi/ ^u liquid tides 9 ! fluid int]ior ( our e>?4 ,! nature ( ! e>?'s int]ior is1 h[ev]1 a "q on :i* !re is a div]sity ( op9ion4 ,"o doctr9e1 :i*1 until rec5t ye>s1 receiv$ mu* support1 0 t ! int]ior ( ! e>? 0 a res]voir ( molt5 matt] conta9$ )9 a ?9 cru/4 ,hopk9s %[$ t ! lea/ possible ?ickness ( su* a cru/ mu/ be f #hjj or #a1jjj miles1 o!rwise ! motions ( precession & nutation w\ld be subject to int]f]5ce4 ,m4 ,delauney object$ to ! views ( ,hopk9s1 on ! supposition t ! fluid int]ior ( ! e>? _h a c]ta9 viscosity4 ,sir ,william ,?omson arrives at ! conclusion t ! e>? on ! :ole mu/ be m rigid ?an a cont9u\s solid globe ( glass4 ,mr4 ,george ,h4 ,d>w9's inve/igations on ! bodily tides ( visc\s or semi-ela/ic sph]oids t5d to /r5g!n ! argum5ts ( ,sir ,william ,?omson4 ,"s philosoph]s hold ! view t ! c5tral portion ( ! e>?1 al?\gh int5sely hot1 is solid by pressure1 :il/ ! out] cru/ is solid by cool+4 ,betwe5 ! two !re is a %ell ( liquid or visc\s molt5 matt]4 ,ano!r argum5t is1 t al?\gh ! int]ior ( ! globe may be solid1 x is only reta9$ 9 t condition by an imm5se pressure1 on ! relief ( :i* x is liquefi$--x is pot5tially liquid4 ,z ^! views1 & ! argum5ts = & aga9/ !m1 are to be f\nd 9 all mod]n text-books ( geology1 we w at once proce$ to consid] ! effect ( sol> & lun> attractive influ5ces 9 produc+ e>?quakes ^u a globe :i* is ei!r solid1 p>tially solid1 or :i* has an int]ior :olly liquid4 ,effect ( ! attractive influ5ces ( ! sun & moon4--,9 #ahed ,m4 ,f4 ,zant$es*i put =w>d ! view--t x is probable !re is a cont9ual t5d5cy ( ! e>? to protub]ance 9 ! direction ( ! radii vectores ( ! two lum9>ies :i* attract x4 ,9 consequ5ce ( ^! protub]ances1 p5dulums ought at "o "t to sw+ m sl[ly ?an at o!rs4 ,zant$es*i rem>ks t ! p]iods ( e>?quakes appe> to confirm su* a view1 insomu* z !y occur m (t5 at ! syzygies1 or epo* ( ! spr+ tides1 ?an at neap tides--an obs]vation f\nd 9 ! works ( ,georges ,baglivi 7#agjc7 & ,joseph ,toaldo 7#aggj74abi ,pr(4 ,p]rey1 ( ,dijon1 :o did s mu* = seismology1 held ! view t ! prepond]ance 9 ! numb] ( e>?quakes felt at p>ticul> seasons 0 possibly due to ! attractive influ5ce ( ! sun & moon produc+ a tide 9 ! fluid int]ior ( ! e>?1 :i*1 act+ on ! solid cru/1 produc$ fractures4 ,rudolf ,falb1 ^: writ+s h ( late ye>s attract$ consid]able att5tion1 br+s =w>d views :i* may be reg>d$ z amplifications ( ^? sugge/$ by ,p]rey4 ,accord+ to ,falb1 ! inn] portion ( ! e>? mu/ be reg>d$ z fluid4 ,9 ! cru/ above ?is fluid res]voir are cracks & *annels1 into :i*1 by ! attraction ( ! moon & sun1 ! fluid is drawn4 ,on ent]+ ^! cracks cool+ takes place1 toge!r ) explosions ( gas & subt]ranean volcanic di/urbances4 ,! attractions produc+ ! int]nal tides requir$ by ,falb are *iefly dep5d5t ^u ! foll[+ factors3-- #a4 ,! ne>ness & di/ance ( ! sun f ! e>? 7,janu>y #a & ,july #a74 #b4 ,! position ( ! moon ) reg>d to ! e>?1 :i* 9 e tw5ty-sev5 days is once ne> & once di/ant4 #c4 ,! phases ( ! moon--:e!r full or new moon 7syzygies71 or :e!r fir/ or la/ qu>t] 7quadratures74 #d4 ,! equ9oxes1 ! position ( ! sun 9 ! equator1 & ! relative position ( ! e>?4 #e4 ,! position ( ! moon relative to ! equator4 #f4 ,! concurr5ce ( ! #8c5trifugal =ce' ( ! e>? ) ! la/ qu>t] ( ! moon4 #g4 ,! entrance ( ! moon on ! ecliptic--! s-call$ nodes4 ,assum+ t e>?quakes are :olly consequ5t on ^! attractions1 x at once becomes possible to pr$ict _! occurr5ce4 ,?is ,falb does1 & :5 8 pr$ictions h be5 fulfill$ he has c]ta9ly ga9$ notoriety4 ,he comm5c$ by ! pr$ictions ( great /orms4 ,9 #ahgc he pr$ict$ ! de/ructive e>?quake ( ,belluno1 :i* e>n$ = himself a eulogi/ic poem1 :i* he has republi%$ 9 8 #8,g$ank5 und ,/udi5 b] ,vulkanismus4' ,aft] ?is1 9 #ahgd1 he pr$ict$ ! eruption ( ,etna4 ,he also expla9$ :y1 9 ,b4,c4 #djjj1 !re %\ld h be5 a great flood1 & = ,a4,d4 #fdjj he pr$icts a repetition ( su* an occurr5ce4 ,:5 we approa* ! "q ( ! ext5t to :i* ! attraction ( ! sun & moon may influ5ce ! production ( e>?quakes1 a "q :i* we h to answ] is1 :e!r x is likely t ! attractive p[] ( ! moon is s great t x c\ld draw up ! cru/ ! e>? beyond its ela/ic limits4 ,we "k :at x c d ) wat]4 ,x c lift up a hemisph]ical %ell #h1jjj miles 9 diamet] ab\t two or ?ree feet high] at its cr[n ?an x lifts ! e>?4 ,ev5 suppos+ ! solid cru/ to be lift$ #ajj times ! app>5t rise ( ! tide1 is x likely t a hemisph]ical ar* #h1jjj miles 9 diamet] :5 x is rais$ #bjj feet at its cr[n c\ld by any possibility suff] fracture8 ,if an ar* is #ab1jjj miles 9 l5g?1 all t we "h ask is1 :e!r ! mat]ials :i* compose ! ar* are suffici5tly ela/ic to all[ !mselves to be s f> /ret*$ t ! cr[n may be rais$ #bjj feet4 ,! result :i* we %\ld arrive at is app>5tly s obvi\s t actual calculation seems h>dly necess>y4 ,if we reg>d ! e>? z be+ solid1 ! "q resolves itself into ! inquiry z to :e!r a column ( rock1 :i* is equal 9 l5g? to ! diamet] ( ! e>?1 or ab\t #h1jjj miles1 c be elongat$ #bjj feet )\t a fracture4 ,?is is equival5t to ask+ :e!r a piece ( rock "o y>d 9 l5g? c be /ret*$ "o sev5ty ?\s&? ( a foot4 ,consid]+ t ?is is a quantity :i* is sc>cely appreciable "u ! mo/ p[]ful ( our microscopes1 we mu/ also reg>d ?is z a "q :i* x is h>dly necess>y to ent] into calculations ab\t be=e giv+ x an answ]4 ,to v>y ! me?od ( treat+ su* a "q1 may we n ask :at is ! utmo/ limit to :i* x w\ld be possible to raise up or /ret* ! cru/ ( ! e>? )\t dang] ( a fracture8 ,?us1 = in/ance1 to :at ext5t might a column ( rock be elongat$ )\t dang] ( its be+ brok58 ,f :at we "k ( ! t5acity ( mat]ials l brick & _! moduli ( ela/icity1 x w\ld seem possible to /ret* a b> ( rock #h1jjj miles 9 l5g? = approximately half a mile be=e expect+ x to break4 ,z to :e!r !re is a wave1 ! height ( :i* is equal to half ?is quantity1 runn+ r\nd our e>? z successive portions ( its surface pass b5ea? ! attract+ influ5ces ( ! sun & moon1 is a ph5om5on :i*1 if x exi/s1 w\ld probably long ago h met ) a practical demon/ration4 ,! de=mation :i* a solid globe or sph]ical %ell w\ld exp]i5ce "u ! attractive influ5ces ( ! sun & moon has be5 inve/igat$ by ,lam1 ,?omson1 ,d>w91 & o!r physici/s & ma!maticians4 ,a conclusion t we are l$ to z "o result ( ^! valuable inve/igations is1 t if ! int]ior ( ! e>? be fluid1 & cov]$ ) a ?9 %ell1 !n enorm\s ela/ic tides mu/ be produc$4 ,a consequ5t ph5om5on1 dep5d5t on ! exi/5ce ( ^! tides1 w\ld be a m>k$ regul>ity 9 ! occurr5ce ( e>?quakes4 ,z ?is m>k$ regul>ity does n exi/1 we mu/ conclude t e>?quakes are n due to ! attractive influ5ces ( ! sun & moon act+ ^u ! ?9 cru/ ( ! e>? cov]+ a fluid int]ior4 ,! p]iodicity ( e>?quakes corroborates ! conclusions ( ,sir ,william ,?omson1 :o rem>ks t if ! e>? 7 n extremely rigid ! enorm\s ela/ic tides :i* mu/ result w\ld be suffici5t to lift ! wat]s ( ! ocean up & d[n s t ! oceanic tide w\ld be oblit]at$4 ,assum+ t ! e>? has ! rigidity assign$ to x by ma!matical & physical inve/igators1 we nev]!less h travell+ r\nd our e>?1 foll[+ ! attractions ( ! moon & sun1 a tidal /ress4 ,?is /ress1 impos$ ^u an area 9 a critical /ate1 may cause x to give way1 & ?us be ! orig9 ( an e>?quake4 ,e>?quakes ought !re=e to be m num]\s :5 ^! /resses are ! greate/4 ,! p]iods ( maximum /ress or greate/ pull ex]t$ by ! moon & sun w occur :5 ^! bodies are ne>e/ to our planet--t is1 9 p]igee & p]ihelion1 & aga9 :5 !y are act+ 9 conjunction or at ! syzygies4 ,t e>?quakes are slightly m num]\s at ^! p>ticul> p]iods ?an at o!rs is a /rong reason = believ+ t ! attractions ( ! moon & sun ent] into ! li/ ( causes produc+ ^! ph5om5a4 ,_h !re be5 a /rongly m>k$ di/9ction 9 ! numb] ( e>?quakes occurr+ at ^! p>ticul> seasons z comp>$ ) o!rs1 we might h attribut$ e>?quakes to ! exi/5ce ( ela/ic tides ( a s5sible magnitude4 ,z ! facts /&1 x appe>s t ! maximum pulls ex]t$ by ! moon & sun are only suffici5t to cause a slight prepond]ance 9 ! numb] ( e>?quakes felt at p>ticul> seasons1 & !re=e t ^! pulls only result 9 e>?quakes :5 ! di/ort+ ef=t has be5 ex]t$ on an area :i*1 by volcanic evisc]ation1 ! pressure ( includ$ gases1 & o!r causes1 is on ! v]ge ( yield+4 ,e>?quakes & ! tides4--,if we assume t e>?quakes are 9 _m cases due to ! ov]load+ ( an area & its consequ5t fracture1 su* load+ may occur by ! ris+ ( ! tide4 ,a belief t ! e>?quakes ( ,japan 7 attributable to ! tides may be f\nd 9 ! di>y ( ,ri*>d ,cocks "u ! date ,novemb] #g1 #afah1 :o rem>ks3-- #8,&1 z we retorn$1 ab\t t5 aclock1 hapn$ a greate e>?quake1 :i* caus$ _m p to run out ( _! h[ses4 ,& ab\t ! lyke h[] ! night foll[+ hapn$ an o!r1 ?is c\ntrey be+ mu* subject to !m4 ,& t :i* is comunely m>kd1 !y allwais hap5 at a hie wat] 7or full sea72 s x is ?\ght x *ause? p] reason is mu* w9d bl[5 into holl[ caves "u gr\nd at a loe wat]1 & ! sea fl[+ 9 aft]1 & /op+ ! passage out1 cause? ^! e>?quakes1 to fynd passage or v5t = ! w9d %ut up4'#acj ,al?\gh we may n acquiesce 9 ,cock's views respect+ ! imprison$ w9d1 x w\ld seem t a comp>ison ( ! occurr5ce ( e>?quakes & ! /ate ( ! tide w\ld be a legitimate rese>*4 ,inasmu* z ! /resses :i* are br\ght to be> ^u an area by ! ris+ ( ! tide are s v mu* great] ?an ^? due to b>ometrical *anges1 x is n unlikely t a m>k$ connection w\ld be f\nd4 ,b x mu/ be rememb]$ t because rese>*es1 s f> z !y h gone1 t5d to %[ t e>? movem5ts are m frequ5t :5 an area is reliev$ ( a load1 x is n unlikely t ! greate/ numb] ( e>?quakes may be f\nd to occur at l[ wat]4 ,pr(4 ,w4 ,s4 ,*apl9 attempt$ to make ?is inve/igation 9 ,japan1 b n be+ able to obta9 ! necess>y in=mation respect+ ! tides1 0 compell$ to rel9qui% ?is int]e/+ "w4 ,e foot ( rise 9 a tide is equival5t to a load be+ plac$ on ! area ov] :i* ! tide takes place ( sixty-two p\nds to ! squ>e foot4 ,?is load is n ev5ly di/ribut$1 b /ops abruptly at a coa/ l9e4 ,la/ly1 x may be obs]v$ t _m coa/ l9es are n simultane\sly subject$ to /resses consequ5t ^u ?is load4 ,japan1 = in/ance1 may be reg>d$ z an ar* plac$ horizontally4 ,! area ne> ! cr[n ( ?is ar* is load$ by ! tidal wave cross+ ! ,pacific be=e ! areas ne> ! abutm5t1 & f>!r !re is a horizontal pressure at ! cr[n :i*1 if ,japan 7 l a raft1 w\ld t5d1 z ! tide advanc$1 to /raight5 its b[-l =m1 b z ! wave pass$ its abutm5ts to increase its curvature4 ,pr(4 ,g4 ,d>w9 has calculat$ ! am\nt ( rise & fall ( a %ore l9e due to tidal loads 7see p4 #ccf1 #8,e>? ,pulsations'74 ,! result ( ^! calculations app>5tly indicates t ^! loads may h a consid]able influ5ce ^u ! /ability ( an area 9 a m or less critical condition4 ,mr4 ,j4 ,c>ru!rs sugge/s t tidal action may hold a g5]al b indirect relation%ip to volcanic & seismic action by ! ret>dation x causes on ! e>?'s rotation4 ,by ?is ret>dation ! pol> axis t5ds to l5g!n1 & t5sile /resses are induc$1 result+ 9 fracture4 ,! fluid int]ior ( ! e>?1 be+ no long] re/ra9$1 w\ld move polew>ds1 &1 leav+ equatorial portions unsupport$1 ?is w\ld gradually collapse4 ,! prim>y fractures w\ld be nor? & s\?1 :ile ! second>y fractures w\ld be ea/ & we/4#aca ,t ! rise ( ! tide is accompani$ by a great] p]colation ( wat] to volcanic foci1 :i*1 9 consequ5ce1 assume a great] /ate ( activity1 is a !ory :i* 0 advanc$ _m ye>s ago4 ,to det]m9e h[ f> tides may directly be connect$ ) e>?quakes1 ! necess>y records h yet to be exam9$4 ,v>iations 9 atmosph]ic pressure4--,:5 we consid] ! imm5se load :i*1 by a sudd5 rise ( ! b>omet]1 is plac$ ^u ! area ov] :i* ?is rise takes place1 x is n difficult to imag9e t ?is rise may occasionally be ! f9al cause :i* makes ! cru/ ( ! e>? to give way4 ,a b>ometric rise ( an in* is equival5t to a load ( ab\t sev5ty-two p\nds be+ put ^u e squ>e foot ( area ov] :i* ?is rise takes place4 ,on ! o!r h&1 a fall 9 ! b>ometric column indicates t a load has be5 remov$1 & :atev] ela/ic ef=t may be ex]t$ by subt]ranean =ces 9 endeav\r+ to escape1 be+ met by less resi/ance1 !y may bur/ ^! bonds1 & an e>?quake w result4 ,= reasons su* z ^! ! f9al cause ( e>?quakes has (t5 be5 attribut$ to v>iations 9 atmosph]ic pressure4 ,9 ,japan !re are practically z _m e>?quakes ) a high b>omet] z ) a l[ "o4 ,! ext5t to :i* b>ometric fluctuations h act$ z f9al causes 9 ! production ( e>?quakes may be judg$ ( by a comp>ison ( ! times ( b>ometric v>iation & ! times at :i* e>?quakes h occurr$4 ,?ree important laws ( b>ometric v>iation are ! foll[+3-- #a4 ,9 ! _w g5]ally ! av]age b>ometric pressure is highe/ 9 w9t]4 7,exceptions occur ne> ,icel& & 9 ! ,nor? ,pacific47 #b4 ,! summ] & w9t] mon?ly mean b>omet] diff]s lea/ ne> ! equator & ov] ! great oceans4 ,!y diff] mo/ ov] ! great cont95ts & g5]ally ) increas+ latitude4 #c4 ,! greate/ numb] ( b>ometrical fluctuations usually take place 9 w9t]4 ,inasmu* z !re are g5]ally m e>?quakes 9 w9t] ?an 9 summ]1 ! fir/ ( ^! laws w\ld indicate t ?is might be due to ! great] load :i* acts ^u ! cru/ ( ! e>? at t season4 ,! second law w\ld indicate t ! di/9ction betwe5 ! w9t] & summ] e>?quakes ought to be mo/ m>k$ 9 high latitudes1 :i*1 if we ref] to ! table on p4 #beg1 we obs]ve to be borne out by ! results ( obs]vation4 ,! c\ntries :]e !re are z _m e>?quakes 9 w9t] z 9 summ] are *iefly ^? 9 l[ latitudes4 ,! numb] ( ^! c\ntries f :i* we h records are1 h[ev]1 few4 ,facts oppos$ to ! idea t e>?quakes may be caus$ by an increase ( b>ometric pressure are ! results ( obs]vations l ^? ( ,s*midt & ,rossi1 :i* %[ t e>?quakes *iefly occur ) a l[ b>omet]4 ,assum+ t ^! latt] obs]vations w be f\nd by future inve/igators to be g5]ally true1 we mu/ conclude t ! relief ( atmosph]ic pressure has an influ5ce ^u ! occurr5ce ( e>?quakes4 ,su* a conclusion w\ld p>tially accord ) ! ?ird b>ometrical law1 or ! fact t !re are m occasions on :i* we get a l[ b>omet] dur+ ! w9t] mon?s4 ,o!r writ]s :o h exam9$ ?is "q are ,volg]1 ,kluge1 ,&rs1 & ,poly4 ,! latt] inve/igator s\ght a connection betwe5 e>?quakes & revolv+ /orms1 9 ! c5tres ( :i* !re is usually an abnormal decrease ( atmosph]ic pressure4 ,if an area ov] :i* su* a sudd5 *ange 9 pressure took place 0 9 a critical /ate1 x is n difficult to see t /orms su* z ,poly ref]s to might sometimes be accompani$ by e>?quakes4 ,fluctuations 9 temp]ature4--,inasmu* z fluctuations 9 temp]ature are gov]n$ by ! sun1 x may at once be said t !re is a connection betwe5 e>?quakes & read+s ( ! !rmomet]4 ,c]ta9ly e>?quakes occur mo/ly dur+ ! cold mon?s or 9 w9t]4 ,simil>ly1 z *anges 9 temp]ature are s closely connect$ ) b>ometric fluctuations1 & ^! are said to h a direct influ5ce ^u ! yield+ ( ! e>?'s cru/1 seismic ph5om5a are indirectly l9k$ to fluctuations 9 temp]ature4 ,a rise 9 temp]ature is usually accompani$ by a fall 9 ! b>omet]1 & ?is 9 turn may be a condition fav\rable = ! occurr5ce ( an e>?quake4 ,if we reg>d sol> heat z an ag5t caus+ expansions or contractions 9 ! e>?'s cru/1 !n fluctuations 9 temp]ature become an imm$iate cause ( e>?quakes4 ,! probability1 h[ev]1 is t sol> heat has little or no connection ) ! f9al cause produc+ e>?quakes1 al?\gh at ! same "t co9cid5ces betwe5 ! occurr5ce ( e>?quakes & unusual fluctuations 9 temp]ature may f "t to "t be obs]v$4 ,w9ds & e>?quakes4--,al?\gh x may be admitt$ t high w9ds ex]t enorm\s pressures ^u m\nta9 ranges1 & might occasionally give rise to /resses caus+ rocky masses 9 un/able equilibrium to give way1 ! co9cid5ces :i* h be5 e/abli%$ betwe5 ! occurr5ce ( /orms & e>?quakes c usually only be reg>d$ z occurr5ces :i* h syn*ronis$ by *ance4 ,/orms are usually accompani$ ) a b>ometric depression1 & ! relation ( dim9utions 9 atmosph]ic pressure to e>?quakes has be5 discuss$4 ,ra9 & e>?quakes4--,x has already be5 %[n t e>?quakes h occasionally be5 f\nd to co9cide ) ra9 & ra9y seasons4 ,:e!r ! saturation ( ! gr\nd ) moi/ure or ! p]colation ( ! same to volcanic foci may be a direct effect produc+ e>?quakes x is difficult to say4 ,! probability1 h[ev]1 is t1 ra9 be+ dep5d5t on ph5om5a l *anges 9 temp]ature1 b>ometric fluctuations1 & w9ds1 we mu/ reg>d x & ! e>?quakes :i* happ5 to co9cide ) ^! precipitations ( moi/ure z congru5t effects ( m g5]al causes4 ,conclusion4--,al?\gh x w\ld be an easy matt] to discuss ! relation%ip ( e>?quakes & o!r ph5om5a1 we mu/ conclude t ! prim>y cause ( e>?quakes is endog5\s to our e>?1 & t exog5\s ph5om5a1 l ! attraction ( ! sun & moon & b>ometric fluctuations1 play b a small "p 9 ! actual production ( ^! ph5om5a1 _! greate/ effect be+ to cause a slight prepond]ance 9 ! numb] ( e>?quakes at p>ticul> seasons4 ,!y may1 !re=e1 sometimes be reg>d$ z f9al causes4 ,! majority ( e>?quakes are due to explosive ef=ts at volcanic foci4 ,! great] numb] ( ^! explosions take place b5ea? ! sea1 & are probably due to ! admission ( wat] ?r\gh fissures to ! heat$ rocks b5ea?4 ,a small] numb] ( e>?quakes orig9ate at actual volcanoes4 ,"s e>?quakes are produc$ by ! sudd5 fracture ( rocky /rata or ! production ( faults4 ,?is may be attributable to /resses br\ght ab\t by elevatory pressure4 ,la/ly1 we h e>?quakes due to ! collapse ( und]gr\nd excavations4 ,,*apt] ,,xviii4 ,,pr$iction ,,( ,,e>?quakes4 ,g5]al nature ( pr$ictions--,pr$iction by ! obs]vation ( unusual ph5om5a 7alt]ation 9 ! appe>ance & ta/e ( spr+s2 und]gr\nd noises2 prelim9>y tremors2 e>?quake prophets--w>n+s furni%$ by animals1 c47--,e>?quake w>n+4 ,g5]al nature ( pr$ictions4--,ev] s9ce seismology has be5 /udi$1 "o ( ! *ief aims ( its /ud5ts has be5 to discov] "s means :i* w\ld enable !m to =etell ! com+ ( an e>?quake1 & ! attempts :i* h be5 made by work]s 9 v>i\s c\ntries to correlate ^! occurr5ces ) o!r well-m>k$ ph5om5a may be reg>d$ z attempts 9 ?is direction4 ,ability to h]ald ! approa* ( ^! calamities w\ld unque/ionably be an ine/imable boon to all :o dwell 9 e>?quake-%ak5 c\ntries1 & ! attempts :i* h be5 made bo? "h & 9 o!r places are extremely praisewor?y4 ,9 almo/ all c\ntries :]e e>?quakes are ( common occurr5ce ^! movem5ts ( ! e>? h be5 m or less connect$ ) c]ta9 ph5om5a :i*1 9 ! popul> m9d1 are suppos$ to be associat$ ) an approa* ( an e>?quake4 ,if pr$ictions 7 giv5 9 g5]al t]ms1 & !y only ref]r$ to "t1 inasmu* z on ! av]age !re are 9 ! _w sev]al %ak+s p] day1 we %\ld always f9d t pr$ictions 7 v]ifi$4 ,we might ev5 g fur!r & pr$ict t on c]ta9 days e>?quakes w\ld occur 9 c]ta9 c\ntries1 & /ill f9d t 9 _m in/ances our suppos$ p[] ( =esight _h n deceiv$ u4 ,?us1 = in/ance1 9 ,japan1 :]e on ! av]age !re are probably "o or two %ak+s e day1 if progno/ications 7 nev] correct !re w\ld be a violation ( ! laws ( *ance4 ,:at is requir$ f ^? :o und]take to =ew>n u ( an e>?quake is an indication n only ( ! "t at :i* ! di/urbance w happ51 b also an indication ( ! area 9 :i* x is to occur4 ,^? :o dwell 9 an area :]e !re are c]ta9 well-def9$ p]iods dur+ :i* seismic activity is at a maximum--if t5 or f\rte5 days %\ld h pass$ )\t a %ock--might1 9 _m in/ances1 f9d t a prophecy t !re w\ld be an e>?quake )9 ! next few days w\ld prove itself correct4 ,also1 if a sev]e %ock _h tak5 place1 a prophecy t !re w\ld be a second or ?ird small] di/urbance )9 a %ort p]iod w\ld also meet ) v]ification4 ,c]ta9 p]sons ) :om ,i am intimate appe> to h p]suad$ !mselves t !y c =etell ! com+ ( an e>?quake by ! sultry /ate ( ! atmosph]e or a c]ta9 oppressiv5ess !y feel1 & an in/9ctive feel+ arises t an e>?quake is at h&4 ,x is said t a few m9utes be=e _m ( ! %ocks :i* %ook ,new ,engl& betwe5 #ahbg & #ahdg p c\ld =etell ! com+ di/urbance by an alt]ation 9 _! /oma*4#acb ,no d\bt _m :o dwell 9 e>?quake c\ntries1 & h be5 al>m$ by e>?quakes1 are at times subject to n]v\s expectancy4 ,! au?or has _h su* s5sations himself1 due1 p]haps1 to a k t x 0 ! e>?quake season1 t !re _h be5 no di/urbance = "s weeks1 & a consequ5t increas+ /ate ( n]v\s pres5tm5ts4 ,9 consequ5ce ( ?is1 n only has he c>efully prep>$ 8 in/rum5ts = ! com+ %ock1 b he has writt5 & telegraph$ to fri5ds to d ! same4 ,sometimes ^! guesses h prov$ correct4 ,"o rem>kable in/ance 0 a few h\rs prior to ! sev]e %ock ( ,febru>y #bb1 #ahhj1 :5 he communicat$ ) 8 fri5ds 9 ,yokohama & ask$ !m to see t _! in/rum5ts 7 9 good ord]4 ,(t5]1 h[ev]1 8 progno/ications h be5 incorrect4 ,! po9t 9 connection ) ?is subject :i* he wi%es to be rem>k$ is1 t ! in/ances :]e e>?quakes occurr$ %ortly aft] ! receipt ( 8 lett]s are c>efully rememb]$1 & (t5 m5tion$1 b ! in/ances 9 :i* e>?quakes did n occur appe> to be entirely =gott54 ,he is l$ to m5tion ^! facts because !y appe> to be an exp]im5tal pro( ( :at has tak5 place 9 bygone times1 & :at /ill takes place1 especially among/ savages--namely1 t ! record ( t :i* is rem>kable survives1 :il/ t :i* is ( e-day occurr5ce quickly dies4 ,_h ! records ( all progno/ications be5 pres]v$1 ! probability is t we %\ld f9d t !y _h1 9 ! majority ( cases1 be5 incorrect1 :il/ x w\ld h be5 b 9 v few in/ances !y _h be5 fulfill$4 ,pr$iction by ! obs]vation ( natural ph5om5a4--,! above rem>ks may p]haps help u to und]/& ! progno/ications ( ! anci5t philosoph]s ab\t :i* ,pr(essor ,antonio ,fav>o1 ( ,padua1 has writt54#acc ,cic]o 9 ! #8,de ,div9atione1' speak+ on ?is subject1 says t #8,god has n pr$ict$ s mu* z ! div9e intellig5ce ( man4'--#8,non ,deus prvidet tantum1 s$ et div9i 9 g5ii viri4' ,fav>o reg>ds ^! pr$ictions1 h[ev]1 z ! result ( obs]vations ( nature :i* %[ x is possible t indications ( com+ e>?quakes _h be5 ann\nc$ by v>iations 9 ! gas giv5 out f subt]ranean s\rces1 ! *ange 9 col\r1 ta/e1 level1 temp]ature ( ! wat] 9 spr+s1 c4 ,9 #ahdc a bi%op ( ,is*ia =ew>n$ 8 p ( a conn+ e>?quake1 & ?us 0 in/rum5tal 9 ! sav+ ( _m lives4 ,naturally1 9 an age ( sup]/ition1 ! bi%op w\ld be reg>d$ z a prophet1 b ,fav>o consid]s t ! progno/ication 0 probably due to a k ( premonitory signs z exhibit$ 9 *anges 9 ! *>act]s ( m9]al wat]s4 ,! %ock ( #ahea1 at ,melfi1 0 9 ?is way pr$ict$ by ! ,capu*9 fa!rs1 :o obs]v$ t a lake ne> _! door became fro?y & turbul5t4 ,und]gr\nd noises h l$ p]sons to ! belief t an e>?quake 0 at h&4 ,x 0 9 ?is way t ,vidu>i1 a prison] at ,lima1 pr$ict$ ! de/ruction ( t city4 ,be=e ! e>?quake ( #ahfh1 s sev]ely felt at ,iquique1 ! inhabitants 7 t]rifi$ by l\d subt]ranean noises4 ,t und]gr\nd noises h prec$$ e>?quakes by consid]able int]vals appe>s to be a fact1 b1 at ! same "t1 x mu/ be rememb]$ t simil> noises h (t5 occurr$ )\t an e>?quake hav+ tak5 place4 ,f>m]s pr$ict$ ! e>?quake ( ,/4 ,remo1 9 #ahca1 by und]gr\nd noises4 ,on ! day be=e ! e>?quake :i*1 9 #ahgc1 %ook ,m\nt ,baldo1 ! inhabitants ( ,puos1 a village nor? ( ,lake ,santa ,croce1 he>d und]gr\nd noises4 ,be=e ! e>?quakes :i*1 9 #aghc1 %ook ,calabria & ,sicily1 fi% are said to h appe>$ 9 great numb]s on ! coa/ ( ,sicily1 & ! :irlpool ( ,*>ybdis assum$ an unusual excit$ /ate4 ,x is said t ,ph]ecydes pr$ict$ ! e>?quakes ( ,lac$emon & ,helm out1 by ! ta/e ( ! wat] 9 ! v deep well at ! ca/le ( ,lova94#acd ,! writ] ( an article on ! ,lisbon e>?quake says t #8aft] ! #bd? ,i felt appreh5sive1 z ,i obs]v$ ! same progno/ics z on ! aft]noon ( ,octob] #ca1 t is1 ! wea!r 0 sev]e1 ! w9d nor!rly1 a fog came f ! sea1 ! wat] 9 a f\nta9 ran ( a yell[ clay col\r1 &' he adds1 #8f midnight to ! morn+ ( ! #be? ,i felt five %ocks4'#ace ,at ! pres5t "t ,rudolf ,falb1 foll[+ a !ory bas$ ^u ! attractive influ5ces ( ! sun & moon1 tells u ! "t at :i* we are to expect e>?quakes4 ,t occasionally !re are signs att5dant on e>?quakes1 al?\gh we _c give !m a physical explanation1 we _c d\bt4 ,also we "k t 9 c]ta9 areas e>?quakes are m likely to occur at "o season ?an at ano!r4 ,%\ld e>?quakes be =etold ) ! assi/ance ( k ( ?is description1 ! pr$ictions at once become ! result ( ! application ( c]ta9 natural laws1 & are n to be reg>d$ z pr$ictions 9 ! popul>ly accept$ s5se ( t t]m1 any m ?an ! arrival ( a fri5d is pr$ict$ by ! previ\s receipt ( a telegram ann\nc+ 8 com+4 ,r ?an accr$it ! anci5ts & ^? ( m mod]n times :o1 9 consequ5ce ( _! feel+s1 h record$ ! com+ ( an e>?quake1 ) a k ( premonitory signs1 we might 9 _m in/ances reg>d ! records ( ^? progno/ications z ! survival ( accid5tal guesses1 &1 z su*1 examples ( ! survival ( ! useless4 ,! effect ( accid5tal occurr5ces ( ?is description ^u an un$ucat$ m9d1 9 eng5d]+ sup]/ition1 is a subject :i* has (t5 be5 dwelt ^u1 & ! difficulty ( eradicat+ ! same--z may be judg$ ( by ! foll[+ accid5t :i* came "u ! obs]vation ( ,mr4 ,t4 ,b4 ,lloyd & ! au?or1 9 #ahgc1 :5 travell+ 9 ,newf\ndl&--w be easily appreciat$4 ,at ! "t to :i* ,i ref]1 my companion 0 br++ a canoe d[n ! rapids bel[ ! ,gr& ,pond 9 a c\ntry :i* is practically un9habit$1 & :]e an ,indian trapp] w\ld p]haps be ! only p]son met )1 & ?is n m ?an once a ye>4 ,:il/ %oot+ ! rapids "o ( ! ,indians1 ,reub5 ,s\lian1 %ot at a de] pass+ up "o bank ( ! riv]4 ,t ! de] _h be5 hit 0 te/ifi$ by a trail ( blood :i* bespatt]$ ! rocks4 ,subsequ5tly sev]al m %ots 7 fir$1 & x 0 believ$ by all t ! de] 0 kill$4 ,s\lian quickly foll[$ ! animal to ! spot :]e x 0 suppos$ to h fall54 ,"s "t aft] he return$1 hav+ fail$ to f9d any trace ( ! animal4 ,he 0 greatly agitat$1 b ev5tually became melan*oly1 say+ t ! sudd5 disappe>ance ( ! animal 0 a sure sign t "s ( 8 relations _h sudd5ly di$4 ,ab\t two h\rs aft]w>ds ,mr4 ,lloyd's p>ty met ) a p>ty ( ,indians com+ up ! riv]1 ! fir/ !y _h se5 = f\r weeks1 :o told !m t ,s\lian's si/] _h j di$ on ! coa/4 ,9 ! nor!rn "p ( ,s\? ,am]ica c]ta9 %ocks are anticipat$ by prelim9>y vibrations :i* cause a little bell atta*$ to a ,t-%ap$ frame 7cruz sonante7 to r+4 ,!re are1 h[ev]1 p]sons 7trembloron7 :o are suppos$ to be end[$ ) seismic =esight1 ^: v]dicts are mu* reli$ ^u4 ,9 ,c>accas x is said t ne>ly e /reet 9 ! riv] suburb has an e>?quake ,cass&ra or two4 ,"s ( ^! g s f> n only z to pr$ict ! com+ seisms1 b also ! vicissitudes ( p>ticul> /reets4#acf ,e>?quake prophets are1 h[ev]1 by no means conf9$ to ! new _w1 & _m examples ( !m may be f\nd 9 ! hi/ories ( c\ntries :]e e>?quakes h be5 felt4 ,! /ory ( ! crazy lifegu>dsman :o prophesi$ an e>?quake to take place 9 ,london on ,april #d1 #afia1 is an example4 ,! ,rev4 ,sig4 ,pasquel ,e4 ,p]d9i1 writ+ on ! e>?quakes at ,leghorn 9 #agdb1 says t #8a ,milanese a/rolog] pr$ict$ ?is e>?quake = ,janu>y #bg1 by :i* 8mis=tune0 ! fai? & cr$it giv5 to ! a/rolog] ga9$ him m rev]5ce & hon\r ?an ! prophets & holy gospel4' ,be=e ! "t at :i* he pr$ict$ a second %ock1 p remov$ away f ,leghorn4 ,w>n+s furni%$ by animals4--,a /udy ( ! w>n+s furni%$ by animals is also int]e/+4 ,sev]al ( ! natives 9 ,c>accas possess oracul> quadrup$s1 su* z dogs1 cats1 & j]boas1 :i* anticipate com+ dang]s by _! re/lessness4 ,be=e ! cata/rophe ( #ahab1 at ,c>accas1 a ,spani% /allion broke out f its /able & escap$ to ! highl&s1 :i* 0 reg>d$ z ! result ( ! presci5ce ( a com+ calamity4 ,be=e ! di/urbances ( #ahbb & #ahce1 :i* %ook ,*ili1 imm5se flocks ( sea birds flew inl&1 z if !y _h be5 al>m$ by ! comm5cem5t ( "s suboceanic di/urbance4 ,be=e ?is la/ %ock x is also relat$ t all ! dogs escap$ f ! city ( ,talcahuano4 ,e>?quake w>n+4--,:at has "h be5 said respect+ ! pr$iction ( e>?quakes is necess>ily imp]fect--_m ( ! signs :i* are popul>ly suppos$ to enable p]sons to =etell ! com+ ( an e>?quake hav+ already be5 m5tion$ 9 previ\s *apt]s4 ,t we %all yet be able to prep>e ourselves aga9/ ! com+ ( e>?quakes1 by ! applications ( laws gov]n+ ^! di/urbances1 is n an unreasonable hope4 ,) an electric circuit :i* is clos$ by a movem5t ( ! gr\nd1 we are already 9 a position to w>n ! dwell]s 9 surr\nd+ di/ricts t a movem5t is approa*+4 ,an e>?quake :i* travell$ at ! rate ( f\r seconds to ! mile might1 if x 7 all[$ to close a circuit :i* fir$ a gun at a /ation fifte5 miles di/ant1 give ! inhabitants at t place a m9ute's w>n+ to leave _! h\ses4 ,! inhabitants ( ,au/ralia & ! we/]n %ores ( ! ,pacific might1 by telegraphic communication1 receive eighte5 to tw5ty-five h\rs' w>n+ ( ! com+ ( de/ructive sea waves result+ f e>?quakes 9 ,s\? ,am]ica4 ,al?\gh w>n+s l ^! might h _! value1 t :i* is *iefly requir$ is to w>n ! dwell]s at & ne> an e>?quake c5tre ( com+ di/urbances4 ,:at ! results ( ! obs]vations on e>? tremors w lead to is problematical4 ,%\ld microseismic obs]vation enable u to say :5 & :]e ! m9ute movem5ts ( ! soil w rea* a head1 a valuable contribution to ! insurance ( human safety 9 e>?quake regions w h be5 atta9$4 ,z to :e!r ! movem5ts ( tromomet]s are de/9$ to become b>ometric-l w>n+s ( increas$ activity b5ea? ! e>? cru/1 or :e!r !y are only due to vibrations ( ! e>? cru/ produc$ by v>iations 9 atmosph]ic pressure1 has yet to be inve/igat$4 ,o!r ph5om5a :i* may probably =ew>n u ( ! com+ ( an e>?quake are ph5om5a resultant on ! /resses br\ght to be> ^u ! rocky cru/ previ\s to its fracture1 or ph5om5a due to *anges 9 ! position & condition ( heat$ mat]ials b5ea? ! e>?'s surface4 ,among/ ^! may be m5tion$ electrical di/urbances1 :i* appe> to be s closely relat$ to seismic ph5om5a4 ,at ! "t ( e>?quakes telegraph l9es h be5 di/urb$1 b z to :at may happ5 be=e an e>?quake we h z yet b little in=mation4 ,! subject ( e>?quake w>n+ is ( importance to _m c\ntries1 & is des]v+ ( att5tion4 ,z our k ( e>? movem5ts1 & _! att5dant ph5om5a1 increases1 !re is b little d\bt t laws w gradually be =mulat$1 & 9 ! future1 z telluric di/urbances increase1 a l>ge black ball gradually asc5d+ a /aff may w>n ! inhabitants on ! l& ( a com+ e>?quake1 ) z mu* c]ta9ty z ! ball ^u a pole at _m seaports w>ns ! m>9] ( com+ /orms4 ,,*apt] ,,xix4 ,,e>? ,,tremors4 ,artificially produc$ tremors--,obs]vations ( ,kat]1 ,d5man1 ,airy1 ,palm]1 ,paul--,natural tremors--,obs]vations ( ,zlln]1 ,m4 d',abbadie1 ,g4 ,h4 & ,h4 ,d>w9--,exp]im5ts 9 ,japan--,) seismoscopes1 microphones1 p5dulums--,"w 9 ,italy--,b]telli1 ,c\nt ,malvasia1 ,m4 ,s4 di ,rossi--,in/rum5ts employ$ 9 ,italy--,tromomet]s1 microseismographs1 microphones--,results obta9$ 9 ,italy--9 ,japan--,cause ( microseismic motion4 ,dur+ ! pa/ few ye>s consid]able att5tion has be5 drawn t[>ds ! /udy ( small vibratory motions ( ! gr\nd1 :i* to ! unaid$ s5ses are usually pass$ by )\t recognition4 ,^! motions are call$ e>? tremors4 ,_! discov]y appe>s to h be5 due to accid5t1 & n to ! results ( inductive reason+4 ,no soon] _h philosoph]s contriv$ a/ronomical & o!r in/rum5ts = ! purpose ( mak+ ref9$ measurem5ts & obs]vations ?an !y at once discov]$ t !y _h an enemy to cont5d aga9/ 9 ! =m ( microscopic e>?quakes4 ,artificially produc$ tremors4--,artificial di/urbances ( ?is description exi/ 9 all our t[ns1 & ne> a railway l9e !y are p]ceptible ) e pass+ tra94 ,^? :o h us$ microscopes ( high p[] w readily appreciate h[ small a di/urbance ( ! gr\nd is visible 9 ! app>5t movem5t ( ! object "u exam9ation4 ,capta9 ,kat] f\nd t he c\ld n p]=m 8 p5dulum exp]im5ts 9 ,london on acc\nt ( ! vibrations produc$ by ! roll+ ( c>riages4 ,capta9 ,d5man1 :o made "s obs]vations on artificially produc$ tremors1 f\nd t a goods tra9 produc$ an effect #a1ajj feet di/ant 9 m>%y gr\nd ov] s&/one4 ,v]tically1 h[ev]1 above a tunnel ?r\gh ! s&/one1 ! effects only ext5d$ #ajj feet4 ,a rem>kable example ( ! tr\ble :i* artificially produc$ e>? vibrations h occasion$ ^? :o make a/ronomical obs]vations occurr$ "s tw5ty ye>s ago at ! ,gre5wi* ,obs]vatory4 ,:5 det]m9+ ! collimation error ( ! transit circle by means ( ! reflexion ( a /> 9 a tray ( m]cury1 x 0 f\nd t on c]ta9 nights ! surface ( ! m]cury 0 9 su* a /ate ( trembl+ t ! obs]v]s 7 unable to complete _! obs]vations until long aft] midnight4 ,aft] obta9+ a s]ies ( dates on :i* ^! di/urbances occurr$1 x 0 f\nd t !y co9cid$ ) public & bank holidays1 on :i* days cr[ds ( ! poor] classes ( ,london flock$ to ,gre5wi* ,p>k1 & !re amus$ !mselves ) runn+ & roll+ d[n ! hill on :i* ! obs]vatory is situat$4 ,on ^! occasions x 0 f\nd t ! di/urbances 9 ! m]cury 7 su* t obs]vations c\ld n be made until two or ?ree h\rs aft] ! cr[ds _h be5 turn$ out ( ! neighb\r+ p>k4#acg ,to obviate ?is difficulty ,sir ,george ,airy susp5d$ 8 di% ( m]cury 9 a sy/em ( india-rubb] b&s1 & 9 ?is way succe$$ 9 eat+ ! intrud]s up4 ,lieut5ant-,colonel ,h4 ,s4 ,palm]1 ,r4,e41 :5 engag$ ) ! transit ( ,v5us exp$ition 9 ,new ,zeal&1 9 #ahgd1 0 tr\bl$ ) vibrations produc$ f a neighb\r+ railway4 ,to escape ! enemy he intr5*$ 8 in/rum5ts by plac+ !m 9 pits4 ,) pits #c feet deep he f\nd himself suffici5tly protect$4 ,! di/ance f ! l9e 0 ab\t #djj y>ds1 & ! soil ?r\gh :i* ! di/urbances 7 propagat$ 0 a co>se pebbly gravel4#ach ,be=e ! ,unit$ ,/ates ,naval ,obs]vatory 0 e/abli%$ at ,wa%+ton1 ,pr(essor ,h4 ,m4 ,paul 0 deput$ to make a tremor survey to discov] /able gr\nd4 ,! results ( ^! exp]im5ts 7 exce$+ly int]e/+4 ,by wat*+ ! reflect$ image ( a /> 9 a di% ( m]cury a pass+ tra9 w\ld be notic$ at ! di/ance ( a mile4 ,its approa* c\ld be detect$ by ! trembl+ ( ! image be=e its com+ c\ld be he>d4 ,at "o po9t ( obs]vation ! di/urbance appe>$ to be cut (f by a rav9e4 ,! /rata 0 gravel & clay4#aci ,^! few examples ( artificially produc$ tremors1 to :i* _m m might be add$1 h be5 giv5 because !y tea* u some?+ respect+ _! nature4 ,hi!rto e>? tremors h only be5 reg>d$ z intrud]s1 :i* x 0 necess>y to escape f or de/roy4 ,f :at has be5 said !y appe> to be a sup]ficial di/urbance :i* is propagat$ to an enorm\s di/ance4 ,?is di/ance appe>s to dep5d ^u ! propagat+ m$ium1 ^u ! int5sity ( ! initial di/urbance1 & ^u its duration4 ,9 ! obs]vation ( ^! artificial di/urbances1 :i* are accessible to e "o1 & :i* hi!rto h be5 s neglect$1 we h und\bt$ly a fruitful s\rce ( /udy4 ,natural tremors4--,next let u turn to ^? microscopical di/urbances ( our soil :i* are due to natural causes4 ,?us f> !y seem to h be5 record$ :]ev] in/rum5ts suitable = _! detection h be5 erect$1 & x is n improbable t !y are common to ! surface ( ! :ole globe4 ,"s ( ! m def9ite obs]vations :i* h be5 made ^u e>? tremors 7 ^? made 9 connection ) exp]im5ts on ! deviation ( ! v]tical due to ! attractive influ5ce ( ! moon & sun4 ,pr(essor ,zlln]1 :o inv5t$ ! horizontal p5dulum :i* he us$ 9 ! attempt to measure ! *ange 9 level due to lun> & sol> attraction1 f\nd 8 in/rum5ts s s5sitive t ! read+s 7 always *ang+4 ,! mo/ int]e/+ obs]vations :i* 7 made ^u small di/urbances ( ! soil 7 ^? ( ,m4 d',abbadie1 :o c>ri$ on 8 exp]im5ts at ,abbadia1 9 ,sub]noa1 ne> ,h5daye1 #djj mtres di/ant f ! ,atlantic1 & #fb mtres above sea level4 ,! soil 0 a loamy rock4 ,"h ,m4 d',abbadie con/ruct$ a concrete cone #h mtres 9 height1 :i* 0 pi]c$ d[n ! c5tre by a v]tical hole or well1 :i* 0 cont9u$ two mtres bel[ ! cone into ! solid rock4 ,at ! bottom ( ?is hole or well a pool ( m]cury 0 =m$ :i* reflect$ ! image ( cross wires plac$ at ! top ( ! hole4 ,^! cross wires & _! reflection 7 obs]v$ by means ( a microscope4 ,! obs]vations consi/$ 9 not+ ! displacem5t & azimu? ( ! reflect$ image relatively to ! real image ( ! wires4 ,aft] all[+ ?is /ructure five ye>s to settle1 ,m4 d',abbadie comm5c$ 8 obs]vations4 ,to f9d ! surface ( ! m]cury tranquil 0 a r>e occurr5ce4 ,sometimes ! m]cury appe>$ to be 9 viol5t motion1 al?\gh bo? ! air & neighb\r+ sea 7 p]fectly calm4 ,at times ! reflect$ image w\ld disappe> z if ! m]cury _h be5 di/urb$ by a microscopic e>?quake4 ,! relative positions ( ! images 7 9 "p gov]n$ by ! /ate ( ! tide4 ,altoge!r ! movem5ts 7 s /range t ,m4 d',abbadie did n v5ture any speculations z to _! cause1 b he rem>ks t ! cause ( ! *anges he obs]v$ 7 sometimes nei!r a/ronomical nor !rmometrical4 ,^! obs]vations1 ! pr9cipal object ( :i* 0 to det]m9e *anges 9 level r ?an e>? vibrations1 7 c>ri$ on betwe5 ! ye>s #ahfh & #ahgb4adj ,obs]vations at ,cambridge4--,ano!r in/ructive set ( obs]vations 7 ^? :i* 7 made 9 ! ye>s #ahhj-ahhb1 by ,george & ,horace ,d>w91 9 ! ,cav5di% ,laboratory1 at ,cambridge4 ,! ma9 object 9 ^! exp]im5ts 0 to det]m9e ! di/urb+ influ5ce ( gravity produc$ by lun> attraction4 ,! result :i* 0 obta9$1 h[ev]1 %[$ t ! soil at ,cambridge 0 9 su* an incessant /ate ( vibration t :atev] pull ! moon may h ex]t$ ^u ! in/rum5t :i* 0 employ$ 0 mask$ by ! magnitude ( ! effects produc$ by ! e>? tremors1 & ! exp]im5ts _h1 9 consequ5ce1 to be ab&on$4 ,! pr9ciple ( ?is in/rum5t 0 simil> to "o devis$ by ,sir ,william ,?omson1 & put up by him 9 8 laboratory at ,glasg[4 ,z erect$ by ! bro!rs ,d>w91 at ,cambridge1 x 0 briefly z foll[s3 ,a p5dulum1 :i* 0 a massive cyl9d] ( pure copp]1 0 hung by a copp] wire1 ab\t f\r feet long1 inside a holl[ cyl9drical tube ris+ f a /one support4 ,a small mirror 0 !n hung by two silk fibres1 "o ( :i* 0 fa/5$ to ! bob & ! o!r to ! /one basem5t4 ,a ray ( light s5t f a lamp on to ! mirror 0 reflect$ to a scale sev5 feet di/ant1 & by ?is magnification any motion ( ! bob relatively to ! /one support 0 magnifi$ #ej1jjj times4 ,9 sev]al ways ! app>atus 0 insulat$ f all accid5tal di/urbances4 ,! spot ( light 0 obs]v$ f ano!r room by means ( a telescope4 ,?is in/rum5t 0 s delicate t ev5 at ! di/ance ( sixte5 feet ! %ift+ ( y\r weight f "o foot to ! o!r caus$ ! spot ( light to run along ! scale4 ,s s5sitive 0 ! in/rum5t t1 not)/&+ its be+ cut (f f ! surr\nd+ soil by a tr5* fill$ ) wat] & ! :ole in/rum5t be+ imm]s$ 9 wat] to damp out ! small vibrations1 x w\ld seem t ! gr\nd 0 9 a con/ant /ate ( tremor2 9 fact1 s p]si/5t & irregul> 7 ^! movem5ts t x seem$ impossible to sep>ate !m f ! p]turbations due to ! attraction ( ! moon4#ada ,z a result ( obs]vations l ^!1 ! _w _h gradually =c$ ^u x ! fact t ! gr\nd on :i* we live is probably ev]y:]e 9 :at is practically an incessant /ate ( vibration4 ,?is l$ ^? :o 7 int]e/$ 9 ! /udy ( e>? movem5ts to e/abli% special app>atus = ! purpose ( record+ ^! motions ) ! hope ( ev5tually discov]+ ! laws by :i* !y 7 gov]n$4 ,exp]im5ts 9 ,japan4--,! simpl] =ms ( app>atus :i* h be5 us$ 9 ,japan may be describ$ z delicate =ms ( seismoscopes1 :i*1 9 addition to record+ e>? tremors1 also record ! occurr5ce ( small e>?quakes4 ,a simple contrivance :i* may be us$ = ! purpose ( record+ small e>?quakes c be made ) a small compass ne$le4 ,if a light1 small s5sitive compass ne$le be plac$ on a table1 x w be f\nd t a small piece ( iron l a nail may be pu%$ s ne> to x t ! ne$le assumes a position ( extremely un/able equilibrium4 ,if ! table n[ receives ! slighte/ tap or %ake ?is condition is ov]come1 & ! ne$le flies to ! iron & !re rema9s4 ,by mak+ ! support ( ! ne$le & ! iron ! poles ( an electric circuit x is possible to regi/] ! "t at :i* motion took place ) consid]able accuracy4 ,) crude app>atus l ?is a l>ge numb] ( small e>? di/urbances h be5 record$4 ,ano!r =m ( app>atus1 employ$ 9 ,japan1 has be5 a delicately con/ruct$ circuit clos]4 ,! motions ( ?is in/rum5t 7 record$ by caus+ an electro-magnet to deflect a p5cil :i* 0 trac+ a circle on a revolv+ dial4 ,! revolv+ dial 0 a disc ( wood cov]$ ) pap] fix$ to ! h\r-h& axle ( a common clock4 ,a ?ird =m ( app>atus us$ 9 ,japan consi/$ ( a small piece ( %eet lead ab\t ! size ( a ?reep5ny piece susp5d$ by a %ort loop f a rigid support4 ,project+ f ! lead a f9e wire1 ab\t two in*es 9 l5g?1 pass$ freely ?r\gh a hole 9 a metallic plate4 ,by ! slighte/ motion ( ! support ! small p5dulum ( lead 0 set into a /ate ( tremor & caus$ its po9t] to come 9 contact ) "o or o!r side ( ! hole 9 ! metal plate & ?us to close an electric circuit4 ,a m ref9$ k9d ( app>atus :i* has be5 employ$ 9 ,japan 0 simil> to t us$ by ! ,d>w9s at ,cambridge4 ,?is 0 s arrang$ t any deflection ( ! mirror 0 p]man5t until ! in/rum5t 0 reset1 & 9 ?is way ! maximum di/urbance :i* _h tak5 place betwe5 ea* obs]vation 0 record$4 ,9 addition to ^! & o!r contrivances1 exp]im5ts 7 made ) microphones4 ,! microphones us$ 7 small d\bly po9t$ p5cils ( c>bon ab\t ?ree c5timetres long1 saturat$ ) m]cury1 & support$ v]tically 9 pivot holes bor$ 9 o!r pieces ( c>bon1 :i* 7 ! t]m9als ( an electric circuit4 ,^! microphones 7 screw$ d[n on ! top ( /akes driv5 deeply into ! gr\nd4 ,!y 7 cov]$ ) a glass %ade ?ickly greas$ at its base4 ,! /akes 7 9 ! gr\nd at ! bottom ( a small pit--ab\t two feet squ>e & two feet deep--:i* 0 l9$ ) a box4 ,! box 0 cov]$ ) a lid1 & e>? to ! dep? ( n9e in*es or "o foot4 ,"o ( ^! pits 0 9 ! middle ( a lawn 9 ! front ( my h\se1 & ! o!r 0 at ! foot ( a hill at ! back ( ! h\se4 ,! wires f ! microphone pass$ ?r\gh ! side ( ! box into a bamboo tube & !nce up to my d9+-room & b$-room4 ,9 "o ( ! circuits !re 7 ?ree ,daniell's cells1 a telephone1 & a small galvanomet]4 ,i us$ ! galvanomet] because ,i f\nd t :5 !re 0 suffici5t motion 9 ! microphone to produce a s\nd 9 ! telephone a motion 9 ! ne$le ( a galvanomet] 0 produc$4 ,if 9 any case motion took place 9 ! magnetic ne$le dur+ my abs5ce1 x 0 held deflect$ by a small piece ( iron ) :i* x 0 br\ght into contact by ! movem5t4 ,! s5sitiv5ess ( ! arrangem5t may be judg$ ( f ! fact t if a p]son walk$ on ! grass )9 six feet ( ! microphone1 ea* /ep caus$ a creak 9 ! telephone1 & ! ne$le ( ! galvanomet] 0 caus$ to sw+ & come 9 contact ) ! iron4 ,dogs runn+ on ! grass _h no effect4 ,a small /one "o or two in*es 9 diamet] ?r[n f ! h\se s t x fell ne> to ! microphone pit caus$ a %>p creak 9 ! telephone & a movem5t 9 ! ne$le4 ,! nature ( ! records ,i receiv$ f ?is contrivance may be judg$ ( f ! foll[+ extract f my pap]s4 h4 m4 #ahgi4 ,nov4 #ab? #g #j ,p4,m4 contact ( ne$le #g #b difficult to set ! ne$le #g #c ne$le sw+s & telephone creaks #g #d #g #e #g #f #g #aj #c m sw+s #g #aa aga9 ,"h ,i w5t out1 took away ! cov]+1 & exam9$ ! microphone4 ,no?+ wrong 0 to be obs]v$4 ,all t ,i saw 0 "o small ant4 ,i d n ?9k t ?is c\ld h caus$ ! di/urbance1 because x c\ld n get ne> ! in/rum5t4 ,on ! succe$+ nights ,i exp]i5c$ simil> di/urbances1 & x seem$ z if !y might possibly h be5 ! prelude to sev]al small %ocks :i* occurr$ ab\t ?is "t 7,novemb] #ae1 #af1 & #ag74 ,on ,novemb] #ag1 at #h ,a4,m41 ! ne$le 0 f\nd 9 contact1 & aga9 at #e ,p4,m41 & at #f ,p4,m4 ! %ock ( a small e>?quake 0 felt :i* caus$ a rattl+ s\nd 9 ! telephone = ab\t "o m9ute aft] ! motion _h appe>$ to cease4 ,! ne$le swung consid]ably1 b did n come 9 contact4 ,! great objection to ^! obs]vations is t x is possible t ! movem5ts & s\nds :i* ,i h record$ might1 ) ! exception ( "o case :5 ! %ak+ 0 actually felt1 possibly h be5 produc$ by causes o!r ?an t ( ! movem5t ( ! gr\nd4 ,to det]m9e ?is ,i subsequ5tly put up two di/9ct sets ( app>atus to det]m9e :e!r ! motions ( ea* 7 syn*ron\s4 ,s f> z ,i w5t ?is appe>$ only to be sometimes ! case3--b ?is is a "q difficult to det]m9e1 unless a record] ( "t be add$ to ! app>atus4 ,! greate/ objection to obs]vations ( ?is sort is t ! s5sibility ( ! in/rum5t is n con/ant4 ,aft] a curr5t has be5 runn+ = sev]al days x is no long] s5sible to slight %ocks1 x appe>s z if its resi/ance _h be5 increas$4 ,to ov]come ?is x is necess>y to re%>p5 ! c>bon po9ts & bore out ! pivot holes e ?ree or f\r days4 ,f>!r1 ! batt]y v>ies4 ,?is might to "s ext5t be ov]come by us+ a batt]y ) l>ge plates4 ,^! two causes t5d to r$uce ! s5sitiv5ess ( ! galvanomet]-l record]--! deflection ( ! ne$le gradually becom+ less & less1 & !re=e day by day ne$+ a great] sw+ to br+ x into contact ) ! iron4 ,= reasons su* z ^! ?is in/rum5t1 to be us$ successfully1 appe>s to require consid]able att5tion4 ,ano!r =m ( microphone employ$ by ! au?or consi/$ ( an alum9ium wire /&+ v]tically on a metallic plate1 its upp] end pass+ loosely ?r\gh a hole 9 an alum9ium wire /&>d4 ,! upp] end ( ! v]tical wire 0 load$ ) lead4 ,?is contrivance possesses all ! s5sitiv5ess ( an ord9>y microphone1 :il/1 if x receives a sudd5 impulse1 !re is a sudd5 break 9 ! curr5t1 & ! v]tical wire is ?r[n f "o side to ! o!r ( ! hole 9 ! /&>d4 ,aft] _m mon?s ( tiresome obs]vation ) in/rum5ts ( ?is description1 & aft] elim9at+ all motions :i* might h be5 produc$ by accid5tal causes1 ! g5]al result obta9$ %[$ t 9 ,tokio !re 7 movem5ts ( ! soil to be detect$ e day1 & sometimes _m times p] day1 :i* to ord9>y p]sons 7 pass$ by unnotic$4 ,"w 9 ,italy4--,! mo/ satisfactory obs]vations :i* h be5 made ^u microseismic di/urbances are ^? :i* h be5 made dur+ ! la/ t5 ye>s 9 ,italy4 ,! fa!r ( sy/ematical microseismical rese>* appe>s to h be5 ,fa!r ,timoteo ,b]telli1 ( ,flor5ce4 ,9 #ahgj ,fa!r ,b]telli susp5d$ a p5dulum 9 a cell>1 & obs]v$ x ) a microscope4 ,z ! result ( 8 obs]vations x 0 ann\nc$ t he _h p]ceiv$ ! e>?quakes :i* %ook ,romagna1 al?\gh to ! ord9>y obs]v] 9 ,flor5ce ^! %ak+s _h n be5 p]ceptible4 ,9 #ahgc ,b]telli1 by means ( microscopes fix$ 9 sev]al azimu?s1 made #e1ejj obs]vations on free p5dulums4 ,he also made obs]vations on reflections f ! surface ( m]cury4#adb ,"o result ( ^! obs]vations 0 to %[ t microseismic motions increas$ ) a fall ( ! b>omet]4 ,simil> obs]vations 7 made at ,bologna by ,m4 le ,conte ,malvasia1 & also by ,m4 ,s4 di ,rossi1 ne> ,rome4 ,on ,janu>y #ad1 #ae1 & ,febru>y #be ^! ?ree obs]v]s at _! respective /ations simultane\sly obs]v$ great di/urbances4 ,simil> inve/igations 7 made at ,nice by ,m4 le ,b>on ,pro/4 ,al?\gh d\bt 0 ca/ ^u ,b]telli's obs]vations !y appe> to h be5 ! orig9 ( a s]ies ( microseismical obs]vations1 a di/+ui%$ lead] 9 :i* is ,pr(essor ,rossi1 :o1 9 #ahgd1 f\nd t l>ge e>?quakes 7 almo/ always prec$$ or accompani$ ) microseismical /orms4 ,9 #ahgh ,pr(essor ,rossi work$ ^u ^! small di/urbances ) ! assi/ance ( ! microphone & telephone1 & 8 fir/ results 7 publi%$ by ,pr(essor ,palmi]i4 ,_m ( ,pr(essor ,rossi's obs]vations 7 made 9 ! grotto ( ,roca de ,papa1 #gjj mtres high & eighte5 mtres "u ! soil4 ,"h ov] #f1jjj obs]vations 7 made by means ( microscopes1 on p5dulums ( diff]5t l5g?s1 susp5d$ 9 tubes cut 9 ! solid rock4 ,in/rum5ts employ$ 9 ,italy4--,x is impossible to describe 9 detail ! v>i\s =ms ( app>atus :i* h be5 us$ by ! ,italian inve/igators4 ,a description ( "o or two ( ! m important in/rum5ts may n1 h[ev]1 be out ( place1 inasmu* z !y w assi/ ! read] to und]/& ! mann] 9 :i* ! v>i\s results respect+ ! laws gov]n+ microseismic movem5ts h be5 arriv$ at4 ,! mo/ important ( ^! in/rum5ts is ! ,normal ,tromomet] ( ,b]telli & ,rossi4 ,?is consi/s ( a p5dulum #a metres long1 c>ry+1 by means ( a v f9e wire1 a weight ( #ajj grammes4 ,to ! base ( ! bob a v]tical /ile is atta*$1 & ! :ole is enclos$ 9 a tube t]m9at$1 at its base1 by a glass prism ( su* a =m t :5 look$ ?r\gh horizontally ! motion ( ! /ile c be se5 9 all azimu?s4 ,9 front ( ?is prism a microscope is plac$4 ,inside ! microscope !re is a micromatic scale1 s arrang$ t x c be turn$ to co9cide ) ! app>5t direction ( oscillation ( ! po9t ( ! /ile4 ,9 ?is way n only c ! amplitude ( ! motion ( ! /ile be measur$1 b also its azimu?4 ,! ext5t ( v]tical motion is measur$ by ! up & d[n motion ( ! /ile due to ! ela/icity ( ! support+ wire4 ,?is in/rum5t is %[n 9 ! accompany+ draw+4 ,illu/ration3 ,,fig4 #cg4--,normal ,tromomet]4 ,b1 bob ( p5dulum2 ,p1 prism2 ,m1 microscope2 ,s1 rim ( scale4 ,ano!r app>atus is ! ,microseismograph ( ,pr(essor ,rossi4 ,"h we h an arrangem5t :i* gives automatic records ( slight motions4 ,x consi/s ( f\r p5dulums1 ea* ab\t ?ree feet long1 susp5d$ s t !y =m ! corn]s ( a squ>e plat=m4 ,9 ! c5tre ( ?is plat=m a fif?1 b r long]1 p5dulum is susp5d$4 ,! f\r p5dulums are ea* connect$ j above _! bobs to ! c5tral p5dulum ) loose silk ?reads4 ,fix$ to ! c5tre ( ea* ( ^! ?reads1 & held v]tically by a light spr+1 is a ne$le1 s adju/$ t ea* ?read is depress$ to =m an obtuse angle ( ab\t #aee4 ,^! ne$les =m ! t]m9als ( an electric circuit1 ! o!r t]m9ation ( :i* is a small cup ( m]cury plac$ j bel[ ! l[] end ( ! ne$le4 ,by a horizontal sw+ ( "o ( ! p5dulums ?is arrangem5t causes ! ne$le to move v]tically1 b ) a slightly multipli$ amplitude4 ,by ?is motion ! ne$le comes 9 contact ) ! m]cury1 & an electro-magnet ) a lev] & p5cil is caus$ to make a m>k on a b& ( pap] mov$ by clockwork4 ,! five p5dulums be+ ( diff]5t l5g?s all[s ! app>atus to respond #8to seismic waves ( diff]5t velocities4'#adc ,la/ly1 we h ,pr(essor ,rossi's ,microphone4 ,?is consi/s ( a metallic sw+ arrang$ l ! beam ( a balance4 ,by means ( a movable weight at "o end ( ! beam ?is is s adju/$ t x falls d[n until x comes 9 contact ) a metallic /op4 ,?is c be s adju/$ t a slight tap w cause ! beam to slightly jump f ! /op4 ,! beam & ! /op =m two poles ( an electric circuit1 9 :i* !re is a telephone4 ,! slighte/ motion 9 a v]tical direction causes a fluctuation 9 ! curr5t pass+ betwe5 ! /op & ! beam1 & a consequ5t noise is he>d 9 ! telephone4 ,) in/rum5ts analog\s to ^!1 obs]vations h be5 made by v>i\s obs]v]s 9 all portions ( ,italy1 ext5d+ ov] a p]iod ( t5 ye>s4 ,e precaution appe>s to h be5 tak5 to avoid accid5tal di/urbances1 & ! exp]im5ts h be5 repeat$ 9 a v>iety ( =ms4 ,results obta9$ 9 ,italy4--,! results :i* f "t to "t h be5 ann\nc$ are ( ! greate/ int]e/ to ^? :o /udy ! physics ( ! e>?'s cru/1 & !y appe> to be lead+ to ! e/abli%m5t ( laws ( sci5tific value4 ,x w\ld seem t ! soil ( ,italy is 9 incessant movem5t1 !re be+ p]iods ( excessive activity usually la/+ ab\t t5 days4 ,su* p]iods are call$ seismic /orms4 ,^! /orms are sep>at$ by p]iods ( relative calm4 ,^! /orms h _! great] regul>ity 9 w9t]1 & %>p maximums are to be obs]v$ 9 spr+ & autumn4 ,9 ! mid/ ( su* a p]iod or at its end !re is usually an e>?quake4 ,usually ^! /orms are closely relat$ to b>ometric depressions4 ,to di/+ui% ^! movem5ts f ^? :i* occur "u high pressure1 ! latt] are call$ b>o seismic movem5ts1 & ! =m] vulcano seismic movem5ts4 ,! relation ( ^! /orms to b>ometric fluctuation has be5 obs]v$ to h be5 v m>k$ dur+ ! "t ( a volcanic eruption4 ,at ! comm5cem5t ( a /orm ! motions are usually small1 & "o /orm1 la/+ two or ?ree days1 may be jo9$ to ano!r /orm4 ,9 su* a case ! action may be a local "o4 ,x has be5 obs]v$ t a b>ometrical depression t5d$ to br+ a /orm to a maximum1 :il/ an increase ( pressure w\ld cause x to disappe>4 ,sometimes ^! actions are purely local1 b at o!r times !y may affect a consid]able tract ( l&4 ,if a numb] ( p5dulums ( diff]5t l5g? are obs]v$ at ! same place1 !re is a g5]al simil>ity 9 _! movem5ts1 b x is also evid5t t ! free p]iod ( ! p5dulum m or less di/urbs ! "* ( ! record4 ,! greate/ amplitude ( motion 9 a set ( p5dulums is n rea*$ simultane\sly by all ! p5dulums1 & at e di/urbance ! movem5t ( "o w pr$om9ate4 ,f ?is ,rossi argues t ! "* ( ! microseismical motions is n con/ant4 ,b]telli obs]v$ t ! direction ( oscillation ( ! p5dulums is diff]5t at diff]5t places1 b ea* place w h its p>ticul> direction dep5d5t ^u ! direction ( valleys & *a9s ( m\nta9s 9 ! neighb\rhood4 ,rossi %[s t ! directions ( movem5t are p]p5dicul> to ! direction ( l9es ( faults1 ! lips ( ^! fractures ris+ & fall+1 & produc+ two sets ( waves1 "o set p>allel to ! l9e ( fracture1 & ! o!r p]p5dicul> to su* a direction4 ,^! movem5ts1 accord+ to ,b]telli1 h no connection ) ! w9d1 ra91 *ange ( temp]ature1 & atmosph]ic electricity4 ,illu/ration3 ,,fig4 #ch4 ,! di/urbances1 z record$ at diff]5t t[ns1 are n always /rictly syn*ron\s1 b succe$ ea* o!r at %ort int]vals4 ,if1 h[ev]1 we take mon?ly curves ( ! di/urbances z record$ at diff]5t t[ns 9 ,italy1 we see t ^! are simil> 9 "*4 ,! maximum ( di/urbance occurs ab\t ! w9t] sol/ice1 & ! m9imum ab\t ! summ] sol/ice1 & 9 ?is respect !y exhibit a p]fect accordance ) ! curves drawn by ,mallet to %[ ! p]iodicity ( e>?quakes4 ,! accompany+ curves tak5 f "o ( ,b]telli's orig9al memoirs n only %[ ?is g5]al result b also %[ ! close accord !re is betwe5 ! results obta9$ at diff]5t t[ns dur+ successive mon?s4 ,at ,flor5ce1 be=e a p]iod ( e>?quakes !re is an increase 9 ! amplitude & frequ5cy ( v]tical movem5ts4 ,^! v]tical movem5ts d n appe> to co9cide ) ! b>ometrical di/urbances1 b !y appe> to be connect$ ) ! seismic di/urbances4 ,!y are usually accompani$ ) noises 9 ! telephone1 b z ! microphone is s con/ruct$ z to be m s5sitive to v]tical motion ?an to horizontal motion1 ?is is to be expect$4 ,?is v]tical motion w\ld appe> to be a local action1 inasmu* z ! accompany+ motions ( an e>?quake :i* orig9ates at a di/ance are horizontal4 ,/orms ( microseismical motions appe> to travel f po9t to po9t4 ,sometimes a local e>?quake is n notic$ 9 ! tromomet]1 :il/ "o :i* occurr$ at a di/ance1 al?\gh x may be small1 is di/9ctly obs]v$4 ,to expla9 ?is1 ,b]telli sugge/s ! exi/5ce ( nodes4 ,simil> conclusions 7 arriv$ at by ,rossi :5 exp]im5t+ on diff]5t portions ( ! sides ( ,vesuvius4 ,galli notic$ an augm5tation 9 microseismic activity :5 ! sun & moon are ne> ! m]idian4 ,grablovitz f\nd f ,b]telli's obs]vations a maximum two or ?ree days be=e ! syzygies1 & a m9imum ?ree days aft] ^! p]iods4 ,he also f\nd t ! pr9cipal l>ge di/urbances occurr$ 9 ! middle ( p]iods sep>at+ ! quadrature f ! syzygies1 ! apogee f p]igee1 & ! luni/igi p]iod f ! nodes1 :il/ ! smalle/ di/urbances happ5$ 9 ! middle ( p]iods oppos$ to ^!4 ,p4 ,c4 ,melzi says t ! curves ( microseismical motions1 e>?quakes1 lun> & sol> motions1 %[ a concordance ) ea* o!r4 ,) ! microphone ,rossi he>s s\nds :i* he describes z ro>+s1 explosions1 occurr+ isolat$ or 9 volleys1 metallic & bell-l s\nds1 tick+1 c41 :i*1 he says1 reveal$ natural telluric ph5om5a4 ,sometimes ^! h be5 intol]ably l\d4 ,at ,vesuvius ! v]tical %ocks correspond$ ) a s\nd l volleys ( musketry1 :il/ ! undulatory %ocks gave ! ro>+4 ,"s ( ^! s\nds c\ld be imitat$ artificially by rubb+ toge!r ! conduct+ wires 9 ! same mann] 9 :i* ! rocks mu/ rub aga9/ ea* o!r 9 an e>?quake4 ,o!r s\nds 7 imitat$ by plac+ ! microphone on a vessel ( boil+ wat]1 or by putt+ x on a m>ble slab & scrat*+ & tapp+ ! "u side ( x4 ,^!1 !n1 are "s ( ! m important results :i* h be5 arriv$ at by ! /udy ( microseismic motions4 ,"o po9t :i* seems wor?y ( att5tion is t !y appe> to be m law-abid+ ?an _! m viol5t relations1 ! e>?quakes1 & z ph5om5a 9 :i* natural laws are to be trac$ !y are c]ta9ly des]v+ our att5tion4 ,z to :e!r !y w ev] become ! means ( =ew>n+ ourselves aga9/ e>?quakes is yet problematical4 ,_! sy/ematic /udy1 h[ev]1 w enable u to trace ! progress ( a microseismic /orm f po9t to po9t1 & x is n impossible t we may yet be enabl$ to =etell :]e ! /orm may rea* its climax z an e>?quake4 ,^!1 ,i believe1 are ! views ( ,pr(essor di ,rossi1 :o is at ! pres5t "t engag$ 9 ! e/abli%m5t ( a sy/em ( microseismic obs]vations ?r\gh\t ,italy4 ,be=e ! e>?quake ( ,san ,remo 7,dec4 #f1 #ahgd7 ,rossi's tromomet] 0 9 a /ate ( agitation1 & simil> di/urbances 7 obs]v$ at ,livorno1 ,flor5ce1 & ,bologna4 ,s9ce ,febru>y #ahhc ,i h obs]v$ a tromomet] 9 ,japan1 & su* results z h be5 obta9$ accord ) results obta9$ 9 ,italy4 ,! increase 9 microseismical activity ) a fall ( ! b>omet] is v m>k$4 ,o!r peculi>ities 9 ! behavi\r ( ! in/rum5t w be ref]r$ to "u #8,e>? ,pulsations4' ,cause ( microseismic movem5ts4--,z to ! cause ( tromometric movem5ts1 we h a field = speculation4 ,possibly !y may be due to slight vibratory motions produc$ 9 ! soil by ! b5d+ & crackl+ ( rocks produc$ by _! rise ^u ! relief ( atmosph]ic pressure4 ,if ?is 7 s we %\ld expect simil> movem5ts to be produc$ at ! "t ( an increase ( pressure4 ,rossi sugge/s t !y may be ! result ( an increas$ escape ( vap\r f ! molt5 mat]ials b5ea? ! cru/ ( ! e>?1 consequ5t ^u a relief ( pressure4 ,! simil>ity ( "s ( ! s\nds :i* are he>d ) ! microphone to ^? produc$ by boil+ wat] are sugge/ive ( ?is1 & ,rossi quotes in/ances :5 und]gr\nd noises l ^? :i* we %\ld expect to he> f a boil+ fluid h be5 he>d be=e e>?quakes )\t ! aid ( microphones4 ,"o in/ance 0 t ( ,vidu>i1 a prison] 9 ,lima1 :o1 two days be=e ! %ock ( #ahbd1 repeat$ly pr$ict$ ! same 9 consequ5ce ( ! noises he he>d4 ,a possible cause ( di/urbances ( ?is ord] may be small b sudd5 fluctuations 9 b>ometric pressure1 :i* are visible dur+ a /orm4 ,dur+ a small typhoon on ,septemb] #ae1 #ahha1 :5 9 ! ,kurile ,isl&s1 ,i obs]v$ t ! ne$le ( an an]oid work$ back & =? ) a p]iod ( f "o to ?ree seconds4 ,?is cont9u$ = sev]al h\rs4 ,) e gu/ ( w9d ! ne$le sudd5ly rose & !n imm$iately fell4 ,at times x trembl$4 ,^! movem5ts 7 obs]v$ 9 ! op5 air4 ,! ext5t ( ^! sudd5 v>iations 0 approximately f #jc to #je in*es4 ,beckon+ an increase ( b>ometrical pressure ( "o hundr$? ( an in* z equival5t to a load ( tw5ty million p\nds on ! squ>e mile1 dur+ ?is /orm !re mu/ h be5 ! equival5t ( loads ( f #fj to #ajj million p\nds to ! squ>e mile cont9ually plac$ on & remov$ f a consid]able tract ( ! e>?'s surface4 ,if ! p]iod ( application ( ^! /resses approximately co9cide ) ! natural vibrational p]iod ( ! area affect$1 x w\ld surely seem1 especially :5 we reflect ^u ! effect ( an ord9>y c>riage1 t tremors ( consid]able magnitude ought to be produc$4 ,an inspection ( ! foll[+ few obs]vations tak5 f my note-book = ! same typhoon w sugge/ t ev5 ! l>ge & sl[] v>iations are capable ( produc+ tremul\s motions4 ,"t ,b>omet] h4 m4 read+ #ab #e ,p4,m4 #bijb #ab #aj #bije #ab #ab #bijg #ab #ac #bije #ab #be #biaj #ab #ej #bijj #a #aj #bijj #a #bj #bijg ,,*apt] ,,xx4 ,,e>? ,,pulsations4 ,def9ition ( an e>? pulsation--,indications ( p5dulums--,indications ( levels--,o!r ph5om5a indicat+ ! exi/5ce ( e>? pulsations--,di/urbances 9 lakes & oceans--,ph5om5a resultant on e>? pulsations--,cause ( e>? pulsations4 ,! object ( ! pres5t *apt] is to %[ t f "t to "t x is v probable t sl[ b l>ge wave-l undulations travel ov] or di/urb ! surface ( ! globe4 ,^! movem5ts1 :i* h escap$ our att5tion on acc\nt ( _! sl[ness 9 p]iod1 = want ( ano!r t]m ,i call e>? pulsations4 ,! exi/5ce ( movem5ts su* z ^! may be indicat$ to u by *anges 9 ! level ( bodies ( wat] l seas & lakes1 by ! movem5ts ( delicate levels1 by ! displacem5t ( ! bob ( a p5dulum relatively to "s po9t on ! e>? above :i* x hangs1 & by o!r ph5om5a :i* w be enum]at$4 ,indication ( p5dulums4--,p5dulums :i* h be5 susp5d$ = ! purposes ( seismometrical obs]vations h1 bo? by obs]v]s 9 ,italy & ,japan1 be5 se5 to h mov$ a %ort di/ance out f1 & !n back to1 _! normal position4 ,?is motion has simply tak5 place on "o side ( _! c5tral position1 & is n due to a sw+4 ,! "* ( ^! records is su* t we might imag9e ! soil on :i* ! support ( ! p5dulum _h re/$ to h be5 sl[ly tilt$1 & sl[ly l[]$4 ,!y are ! mo/ m>k$ on ^? p5dulums provid$ ) an index writ+ a record ( its motions on a smok$ glass plate1 :i* index is s arrang$ t x gives a multipli$ repres5tation ( ! relative motion betwe5 x & ! e>?4 ,z motions ( ?is sort might be possibly due to ! action ( moi/ure 9 ! soil tilt+ ! support ( ! p5dulum1 & to a v>iety ( o!r accid5tal causes1 we _c insi/ on !m z be+ c]ta9 indications t !re are sl[ tips 9 ! soil1 b = ! pres5t all[ !m to rema9 z possible pro( ( su* ph5om5a4 ,evid5ce ( displacem5t ( ! v]tical1 :i* are m def9ite ?an ! above1 are ^? made by ,b]telli1 ,rossi1 ,c\nt ,malvasia1 & o!r ,italian obs]v]s1 :o1 :il/ record+ e>? tremors1 h sp5t s mu* "t 9 wat*+ ! vibrations ( /iles ( delicate p5dulums by means ( microscopes4 ,z a result ( ^! obs]vations we are told t ! po9t ab\t :i* ! /ile ( a p5dulum oscillates is v>iable4 ,^! displacem5ts take place 9 v>i\s azimu?s1 & !y appe> to be connect$ ) *anges ( ! b>omet]4 ,i h made simil> obs]vations 9 ,japan4 ,f ?is1 & f ! fact t x is f\nd t a numb] ( diff]5t p5dulums diff]5tly situat$ on ! same area give simil> evid5ce ( ^! movem5ts1 x w\ld h>dly seem t ^! ph5om5a c\ld be attribut$ to causes l *anges 9 temp]ature & moi/ure4 ,m4 ,s4 di ,rossi lays /ress on ?is po9t1 especially 9 connection ) 8 microseismograph1 :]e !re are a numb] ( p5dulums ( unequal l5g? :i* give indications ( a l "*4 ,! direction 9 :i* ^! tips ( ! soil take place--:i* ph5om5a are noticeable 9 seismic z well z microseismic motions--,rossi /ates are relat$ to ! direction ( c]ta9 l9es ( fault+4 ,indications ( levels4--,bubbles ( delicate levels c be easily se5 to *ange _! position ) meteorological v>iations2 b ,rossi also tells u t !y *ange _! position1 sometimes n to return = a long "t1 dur+ a microseismic /orm4 ,"h aga9 we h ano!r ph5om5on po9t+ to ! fact t microseismic di/urbances are ! companions ( sl[ alt]ations 9 level4 ,"o ( ! mo/ pati5t obs]v]s ( levels has be5 ,m4 ,plantam\r1 :o comm5c$ 8 obs]vations 9 #ahgh1 at ,s*]on1 on ! ,lake ( ,g5eva4 ,he us$ two levels1 "o plac$ nor? & s\?1 & ! o!r ea/ & we/4 ,dur+ ! summ] ( #ahgh ! ea/ end rose1 b at ! end ( ,septemb] a depression set 94 ,! diurnal movem5ts _h _! maximum & m9imum at #f & #g4de ,a4,m4 & ,p4,m4 ,! total amplitude 0 #dhi4 ,! v>iations ( ! ea/ & we/ level appe>$ to be due to ! temp]ature1 b ! movem5ts ( ! nor? & s\? level 7 dep5d5t ^u an unkn[n cause4 ,betwe5 ,octob] #a1 #ahgi1 & ,septemb] #cj1 #ahhj1 ! ea/ end fell rapidly1 f ! middle ( ,novemb] up to ,decemb] #bf1 am\nt+ to #hhga4 ,x !n rose #fee to ,janu>y #e1 & !n fell aga94 ,on ,janu>y #bh x rea*$ #hiie1 aft] :i* x rose4 ,betwe5 ,octob] #d1 #ahgi1 & ,janu>y #bh1 #ahhj1 ! movem5t 0 #ieh1 aga9/ #bhjh ( ! previ\s ye>4 ,^! movem5ts 7 n due alone to temp]ature4 ,! nor? & s\? level1 :i* 0 n influ5c$ by ! cold ( ! w9t]1 mov$ #def4 ,9 ! previ\s ye> #dhi4add ,f ,febru>y #ag to ,june #e1 #ahhc1 ! au?or obs]v$ 9 ,tokio ! bubbles ( two delicate levels1 "o plac$ nor? & s\?1 & ! o!r ea/ & we/4 ,!y 7 plac$ "u glass cases on ! head ( a /one column4 ,! column1 :i* is inside a brick build+1 re/s on a concrete f\ndation1 & is ab\t t5 ye>s old4 ,x is 9 no way connect$ ) ! build+4 ,! temp]ature ( ! room has a daily v>iation ( ab\t #a ,fahr4 ,9 bo? ^! levels diurnal *anges are v m>k$4 ,occasionally !y are enorm\sly great4 ,?us1 on ,m>* #be1 ! read+s ( ! s\? end ( ! nor? s\? level 7 z foll[s3-- ,"t ,read+s4 h4 m4 #be?4 #d #jj ,p4,m4 #ajde #d #e #ajc #d #aj #ajb #d #be #aja #d #cj #ajj #d #dj #ih #d #db #iie #d #de #ajj #d #ej #aja #d #ee #aja #e #jj #ajj #bf?4 #g #jj ,a4,m4 #aje ,usually ?is level moves ?r\gh ab\t ?ree divisions p] day4 ,f ,m>* #be to ,may #d x travell$ f #ih to #abg4 ,s9ce !n1 to ,june #e1 x has desc5d$ to #aaf4 ,dur+ ?is p]iod ! ea/ we/ level has be5 comp>atively quiet4 ,"o division ( ! nor? s\? level equals ab\t #b ( arc4 ,_m ( ^! *anges may be due to *anges 9 temp]ature1 v>iations 9 moi/ure1 & o!r local actions4 ,"s ( !m1 h[ev]1 are h>dly explicable on su* assumptions4 ,! fact t ! g5]al direction 9 *ange ( ! v]tical1 z indicat$ by a tromomet] /&+ on ! same column ) ! levels1 %[$ t ! *ange :i* 0 tak+ place 0 r 9 ! column ?an 9 ! in/rum5ts4 ,! fact also t at ! "t ( a b>ometrical depression a pulse-l surge c be se5 9 ! levels1 hav+ a p]iod av]ag+ ab\t ?ree seconds & sometimes am\nt+ to ab\t "o second ( arc1 is a ph5om5on h>dly to be attribut$ to sudd5 fluctuations 9 moi/ure or temp]ature1 b indicates real *anges 9 level4#ade ,9 addition to v>iation 9 ! bubbles ( levels :i* come on m or less gradually1 we h _m record$ in/ances ( sudd5 alt]ations tak+ place 9 ^! in/rum5ts4 ,examples ( :at may h be5 a sl[ oscillat+ motion ( ! e>?'s cru/ are ref]r$ to by ,mr4 ,george ,d>w9 9 a ,report to ! ,briti% ,association 9 #ahhb4 ,"o ( !m 0 made by ,m4 ,magnus ,nyrn1 at ,pulkova1 :o1 :5 engag$ 9 levell+ ! axis ( a telescope1 obs]v$ spontane\s oscillation 9 ! bulb ( ! level4 ,?is 0 on ,may #aj 7,april #bh71 #ahgg4 ,! complete p]iod 0 ab\t #bj seconds1 ! amplitude be+ #ae & #b4 ,"o h\r & f\rte5 m9utes be=e ?is he obs]ves t !re _h be5 a sev]e e>?quake at ,iquique1 ! di/ance to :i* 9 a /raight l9e 0 #aj1fjj kilomtres1 & on an arc ( a great circle1 #ab1ejj kilomtres4 ,on ,septemb] #bj 7#h71 9 #ahfg1 ,mr4 ,wagn] _h obs]v$ at ,pulkova oscillations ( #c1 sev5 m9utes be=e :i* !re _h be5 an e>?quake at ,malta4 ,on ,april #d 7,m>* #bc71 #ahfh1 an agitation ( ! level _h be5 obs]v$ by ,mr4 ,gromadzki1 five m9utes be=e :i* !re _h be5 an e>?quake 9 ,turke/an4 ,simil> obs]vations _h be5 made twice be=e4 ,^!1 h[ev]1 _h n be5 connect$ ) any e>?quakes--at lea/1 ,mr4 ,d>w9 rem>ks--) c]ta9ty4 ,ph5om5a analog\s to ! p5dulum & level obs]vations4--,z examples ( ph5om5a :i* are analog\s to ^? made on p5dulums & levels1 ! foll[+ may be notic$4 ,on ,m>* #bj1 #ahha1 at #i ,p4,m4 a wat*mak] 9 ,bu5os ,ayres obs]v$ t all 8 clocks oscillat+ nor? & s\? sudd5ly began to increase _! amplitude1 until "s ( !m became twice z great z be=e4 ,simil> obs]vations 7 made 9 all ! o!r %ops4 ,no motion ( ! e>? 0 detect$4 ,subsequ5tly x 0 le>nt t ?is correspond$ ) an e>?quake 9 ,santiago & ,m5doza4#adf ,ano!r rem>kable example illu/rat+ ! l ph5om5a is furni%$ by ! obs]vations :i* 7 made on ,decemb] #ba1 #ahfj1 by means ( a b>omet] 9 ,san ,francisco1 :i* oscillat$1 ) p]iods ( re/1 = half an h\r4 ,no %ock 0 felt1 nor is x likely t x 0 a local accid5t1 z x c\ld n be produc$ artificially4 ,on ! foll[+ day1 h[ev]1 a viol5t e>?quake 0 exp]i5c$ at ,santiago4#adg ,at ! "t or %ortly aft] ! great ,lisbon e>?quake1 curi\s ph5om5a 7 obs]v$ 9 di/ant c\ntries1 :i* only appe> to be explicable on ! assumption ( ! exi/5ce ( e>? pulsations4 ,?us at ,am/]dam & o!r t[ns1 *&eli]s 9 *ur*es 7 obs]v$ to sw+4 ,at ,ha>lem wat] 0 ?r[n ov] ! sides ( tubs1 & x is expressly m5tion$ t no motion 0 p]ceiv$ 9 ! gr\nd4 ,at ! ,hague a tall[ *&l] 0 surpris$ at ! cla%+ noise made by 8 c&les1 & ?is ! m s because no motion 0 felt und]foot4 ,unusual di/urbances 9 bodies ( wat]4--,at ! "t ( l>ge e>?quakes x w\ld appe> t e>? pulsations are produc$1 :i* exhibit !mselves 9 c\ntries :]e ! actual %ak+ ( ! e>?quake is n felt1 by di/urbances 9 bodies ( wat]s l lakes & seas4 ,"s rem>kable examples ( ^! di/urbances are to be f\nd 9 ! records ( ! great ,lisbon e>?quake4 ,?is e>?quake1 z a viol5t movem5t ( ! gr\nd1 0 *iefly felt 9 ,spa91 ,portugal1 nor!rn ,italy1 ! s\? ( ,france & ,g]many1 nor!rn ,africa1 ,madeira1 & o!r ,atlantic isl&s4 ,9 o!r c\ntries fur!r di/ant1 z1 = in/ance1 ,great ,brita91 ,holl&1 ,sc&9avia1 & ,nor? ,am]ica1 al?\gh ! records are num]\s1 ! only ph5om5a :i* 7 p>ticul>ly obs]v$ 0 ! sl[ oscillations ( ! wat]s 9 lakes1 ponds1 canals1 c4 ,9 "s in/ances ! obs]v]s especially rem>k t !re 0 no motion 9 ! soil4 ,pebley ,dam1 9 ,d]by%ire1 :i* is a l>ge body ( wat] cov]+ "s ?irty acres1 comm5c$ to oscillate f ! s\?4 ,a canal ne> ,godalm+ fl[$ eight feet ov] ! walk on ! nor? side4 ,coni/on ,wat]1 9 ,cumb]l&1 :i* is ab\t five miles long1 oscillat$ = ab\t five m9utes1 ris+ a y>d up its %ores4 ,ne> ,durham a pond1 =ty y>ds long & t5 broad1 rose & fell ab\t "o foot = six or sev5 m9utes4 ,!re 7 f\r or five ebbs & fl[s p] m9ute4 ,lo* ,lomond rose & fell ?r\gh ab\t two & a half feet e five m9utes1 & all ! o!r lo*s 9 ,scotl& seem to h be5 simil>ly agitat$4 ,at ,%irbrun ,ca/le1 9 ,ox=d%ire1 :]e ! wat] 9 "s moats & ponds 0 v c>efully obs]v$1 x 0 notic$ t ! floods began g5tly1 ! velocity !n increas$1 till at la/ ) great impetuosity !y rea*$ _! full height4 ,"h ! wat] rema9$ = a little :ile1 until ! ebb comm5c$1 at fir/ g5tly1 b f9ally ) great rapidity4 ,at two extremities ( a moat ab\t #ajj y>ds long1 x 0 f\nd t ! s9k+s & ris+s 7 almo/ simultane\s4 ,! motions 9 a pond a %ort di/ance f ! moat 7 also obs]v$1 & x 0 f\nd t ! ris+s & s9k+s ( ! two did n agree4 ,dur+ ^! motions !re 7 sev]al maxima4 ,^! few examples ( ! motions ( wat]s1 )\t any record ( ! motions ( ! gr\nd1 at ! "t ( ! ,lisbon e>?quake1 mu/ be tak5 z examples ( a v l>ge numb] ( simil> obs]vations ( :i* we h detail$ acc\nts4 ,l agitations1 x mu/ also be rememb]$1 7 p]ceiv$ 9 ,nor? ,am]ica & 9 ,sc&9avia1 & if ! lakes ( o!r di/ant c\ntries _h be5 provid$ ) suffici5tly delicate app>atus1 x is n unlikely t simil> di/urbances w\ld h be5 record$4 ,besides ^! movem5ts 9 ! wat]s ( seas & lakes1 at or ab\t ! "t ( great e>?quakes1 we h records ( l movem5ts1 :i* take place z indep5d5t ph5om5a4 ,?us we read t on ,octob] #bb1 #agee1 ! wat]s ( ,lake ,ont>io rose & fell five & a half feet sev]al times 9 ! c\rse ( half an h\r4#adh ,on ,m>* #ca1 #agfa1 ,lo* ,ness rose sudd5ly = ! p]iod ( ?ree-qu>t]s ( an h\r4#adi ,z ano!r example ( ! di/urbance ( wat] at ! "t ( a great e>?quake 9 di/ricts :]e ! e>?quake 0 n felt1 may be m5tion$ ! swell+ ( ! wat]s ( ! ,m>aon1 9 #agdf1 on ! night :5 ,callao 0 ov]:elm$4 ,sudd5 v>iations 9 ! level ( ! wat] h be5 _m times obs]v$ 9 ! ,nor? ,am]ican lakes4 ,! *anges 9 level :i* sometimes take place 9 ! ,g5f] & ,bod5 lakes are suppos$ to h "s relation to ! condition ( ! atmosph]e4 ,a ris+ & fall+ ( especial note took place on ,april #ah1 #ahee4 ,9 ,switz]l& ^! sudd5 *anges are kn[n z #8sei*es' or #8rhuss54' ,f ! obs]vations & calculations ( ,pr(4 ,=el x w\ld seem t ! p]iod ( ! #8sei*es' dep5ds ^u ! dim5sions ( ! lakes2 ! calculat$ p]iods dep5d5t on ! dep?s ( ! lakes be+ approximately equal to ! obs]v$ p]iods4#aej ,w4 ,t4 ,b+ham1 writ+ on ! volcanoes ( ! ,hawaiian ,isl&s1 rem>ks t x is n unusual = ! sea to be agitat$ by great & unusual tides1 & t su* sea waves h n be5 att5d$ ) volcanic eruptions or seismic di/urbances4 ,?us 9 ,may #ahai ! tide rose & fell ?irte5 times4 ,on ,novemb] #g1 #ahcg1 !re 0 an ebb & fl[ ( eight feet e tw5ty-eight m9utes4 ,aga91 on ,may #ag1 #ahda1 l ph5om5a1 unaccompani$ by any o!r unusual occurr5ces1 7 record$4#aea ,ph5om5a :i* may possibly hold a relation%ip to e>? pulsations are ! p]iodical swell+s ( ! ocean on ! coa/ ( ,p]u4 ,dr4 ,c4 ,f4 ,w9sl[1 :o made a long p]iod obs]vation ^u ! coa/ ( ,p]u1 f\nd #8! highe/ tides to prevail at ,callao & ,paita 9 ,decemb] & ,janu>y1' & #8also a s]ies ( enorm\s waves or sea-swells to be ?r[n f "t to "t ^u ! coa/1 v>y+ f tw5ty-f\r to tw5ty-sev5 h\rs 9 cont9uance1 accompani$ by unusual height ( ! tide dur+ ! same p]iod4' ,dur+ ,june & ,july ! ocean 0 unusually tranquil4 ,^! ph5om5a d n appe> to be connect$ ) great atmosph]ic /orms1 nor d !y hold any relation to ! prevail+ w9d4 ,!y increase ) & accompany ! swell+ ( ! tides1 & occur g5]ally1 b n always1 ab\t full moon4 ,sometimes !y break sudd5ly ^u ! coa/4 #8,!y are annual & con/ant 9 _! p]iodicity4' ,! p]iodical swell+s are mo/ noticeable betwe5 ,tumbez #c ,s4,l4 & ! ,*9*a ,isl&s #ad ,s4,l4 ,^! oceanic ph5om5a syn*ronise ) ! p]iodic int5sity ( e>?quake ph5om5a 9 t "p ( ! globe1 & ^! ) tidal movem5ts4#aeb ,o!r ph5om5a possibly attributable to e>? pulsations4--,if we assume t e>? pulsations h an exi/5ce1 ^! _m ph5om5a :i* are o!rwise difficult to und]/& meet ) an explanation4 ,! curi\s effects :i* 7 produc$ 9 ! spr+s at ,toplitz at ! "t ( ! ,lisbon e>?quake may h be5 due to a pulse-l wave4 ,! fl[ ( ! pr9cipal spr+ 0 greatly increas$4 ,be=e ! increase x became turbid & at "o "t /opp$4 ,subsequ5tly x became cle> & fl[$ z usual1 b ! wat] 0 hott] & m /rongly m9]alis$4 ,sudd5 *anges 9 ! fl[ ( und]gr\nd wat]s :i* f "t to "t are obs]v$ may be attribut$ to l causes4 ,second>y e>?quakes su* z occurr$ aft] ! ,lisbon e>?quake1 z = in/ance 9 ,d]by%ire1 may h be5 produc$ by pulsations di/urb+ ! equilibrium ( gr\nd 9 a critical /ate4 ,! fall+ 9 ( subt]ranean excavations is also possibly connect$ ) ^! ph5om5a4 ,possible causes ( e>? pulsations4--,mr4 ,george ,d>w91 9 a report to ! ,briti% ,association 7#ahhb71 has %[n t movem5ts ( consid]able magnitude may occur 9 ! e>?'s cru/ 9 consequ5ce ( fluctuations 9 b>ometrical pressure4 7,a rise ( ! b>omet] ov] an area is equival5t to load+ t area ) a weight1 9 consequ5ce ( :i* x is depress$4 ,:5 ! b>omet] falls1 ! load is remov$ f ! area1 :i*1 9 virtue ( its ela/icity1 rises to its orig9al position4 ,?is fall & rise ( ! gr\nd completes a s+le pulsation47 ,on ! assumption t ! e>? has a rigidity l /eel1 ,mr4 ,d>w9 calculates t if ! b>omet] rises an in* ov] an area l ,au/ralia1 ! load is suffici5t to s9k t cont95t two or ?ree in*es4 ,! tides :i* twice a day load our %ores cause ! l& to rise & fall 9 a simil> mann]4 ,on ! %ores ( ! ,atlantic1 ,mr4 ,d>w9 has calculat$ t ?is rise & fall ( ! l& may be z mu* z #e in*es4 ,by ^! ris+s & fall+s ( ! l& ! incl9ation ( ! surface is s alt]$ t ! /ile ( a plummet susp5d$ f a rigid support ought n always to hang ov] ! same spot4 ,!re w\ld be a deflection ( ! v]tical4 ,9 %ort1 calculations respect+ ! effects ( loads ( v>i\s descriptions1 :i* we "k are by natural op]ations cont9ually be+ plac$ ^u & remov$ f ! surface ( v>i\s areas ( ! e>?'s surface1 indicate t sl[ pulsatory movem5ts ( ! e>?'s surface mu/ be tak+ place1 caus+ v>iations 9 incl9ation ( "o portion ( ! e>?'s cru/ relatively to ano!r4 ,al?\gh x is possible t ph5om5a l ! surg+ ( levels may be attributable to causes l ^!1 we c h>dly attribute ! o!r ph5om5a to su* ag5cies4 ,r ?an seek an explanation f ag5cies exog5\s to our e>?1 we might p]haps ) advantage appeal to ! endog5\s ph5om5a ( our planet4 ,:5 ! b>omet] falls1 :i* we h %[n corresponds to an upw>d motion ( ! e>?'s cru/1 we "k1 f ! results ( exp]im5ts1 t microseismic motions are p>ticul>ly noticeable4 ,z a pictorial illu/ration ( :at ?is really means1 we may imag9e ourselves to be resid+ on ! loosely fitt+ lid ( a l>ge cauldron1 ! relief ( ! ext]nal pressure ov] :i* increases ! activity ( its int]nal ebullition--! j>s att5dant on :i* are gradually propagat$ f _! endog5\s s\rce to ! ext]ior ( our planet4 ,?is travell+ outw>ds w\ld take place mu* 9 ! same way t ! vibrations consequ5t to ! rattle & j> ( a l>ge factory sl[ly spread !mselves f>!r & f>!r f ! po9t :]e !y 7 produc$4 ,admitt+ an action ( ?is description to take place1 x w\ld !n foll[ t ?is extra lib]ation ( gase\s mat]ial b5ea? ! e>?'s cru/ w\ld result 9 an increas$ upw>d pressure f )91 & a t5d5cy on ! "p ( ! e>?'s cru/ to elevation4 ,if we accept ?is z an explanation ( ! increas$ activity ( a tremor indicator1 !n su* an in/rum5t may be reg>d$ z a b>omet]1 measur+ by its motions ! v>iations 9 ! int]nal pressure ( our planet4 ,! relief ( ext]nal pressure & ! increase ( int]nal pressure1 x w be obs]v$1 bo? t5d 9 ! same direction--namely1 to an elevation ( ! e>?'s cru/4 ,?is explanation ( ! increas$ activity ( e>? tremors1 :i* has also be5 sugge/$ by ,m4 ,s4 di ,rossi1 is "h only advanc$ z a speculation1 m probable p]haps ?an _m o!rs4 ,we "k h[ a mass ( sulphur :i* has be5 fus$ 9 ! pres5ce ( wat] 9 a clos$ boil] gives up 9 ! =m ( /eam ! occlud$ moi/ure ^u ! relief ( pressure4 ,9 a simil> mann] we see /eam escap+ f volcanic v5ts & cool+ /reams ( lava4 ,we also "k h[ gas escapes f ! pores & cavities 9 a seam ( coal on ! fall ( ! b>ometrical column4 ,we also "k t c]ta9 wells increase ! height ( _! column "u l conditions4 ,! latt] ( ^! ph5om5a1 result+ 9 an increase 9 ! rate ( dra9age ( an area by its t5d5cy to r5d] su* an area ( less weight1 facilitates its rise4 ,if we foll[ ! views ( ,mr4 ,mallet 9 consid]+ t ! pressures ex]t$ on ! cru/ ( our e>? may 9 volcanic regions be r\ghly e/imat$ by ! height ( a column ( lava 9 ! volcanoes ( su* di/ricts1 we see t 9 ! neighb\rhood ( a volcano l ,cotopaxi ! upw>d pressures mu/ be enorm\sly great4 ,fur!r1 ! ph5om5a ( e>?quakes & volcanoes indicate t ^! pressures are v>iable4 ,be=e a volcano bur/s =? we %\ld expect t !re w\ld be 9 its vic9ity an upw>d bulg+ ( ! cru/1 & aft] its =mation a fall4 ,fur!r1 x is n difficult to conjecture o!r possible means by :i* su* pressures may obta9 relief4 ,%\ld ^! pressures !n f9d relief )\t ruptur+ ! surface1 x is n difficult to imag9e !m z ! orig9ators ( va/ pulsations :i* may be record$ on ! surface ( ! e>? z wave-l motions ( sl[ p]iod4 ,z an explanation ( ! /range movem5ts obs]v$ on seas & lakes1 ,kluge br+s =w>d ! foll[+ /range & rem>kable !ory4 ,! oxyg5 ( ! air is magnetic1 :il/ wat] is diamagnetic & ! e>? magnetic3 we h1 !re=e1 9 our seas & lakes a diamagnetic body ly+ betwe5 & be+1 consequ5tly1 repell$ f two magnetic bodies4 ,by v>iation 9 temp]ature1 ! balance ( repulsions ex]t$ by ! air & ! e>? is de/roy$4 ,?us1 by an elevation ( temp]ature ! air exp&s & fl[s away f ! heat$ area1 :]e1 9 consequ5ce1 !re is less oxyg54 ,! result ( ?is is1 t ! repulsion ( ! air ^u ! wat]s is less ?an t ( ! e>? ^u ! wat]s1 & ! wat]s are 9 consequ5ce rais$ up4 ,by a fall+ ( temp]ature ! wat]s may be depress$1 & by ei!r ( ^! actions waves may be produc$ )\t ! int]v5tion ( e>?quakes or e>? pulsations4 ,! m def9ite k9ds ( in=mation :i* we h to br+ =w>d1 t5d+ to prove ! exi/5ce ( e>? pulsations1 too sl[ 9 p]iod to be exp]i5c$ by ord9>y obs]v]s1 are ^? :i* appe> to be resultant ph5om5a ( great e>?quakes4 ,! ph5om5a t we are c]ta9 ( 9 connection ) e>? vibrations1 :e!r ^! vibrations are produc$ artificially by explosions ( dynamite 9 bore-holes1 or :e!r !y are produc$ naturally by e>?quakes1 are1 fir/1 t a di/urbance z x dies out at a giv5 po9t (t5 %[s 9 ! diagrams obta9$ by seismographs a decrease 9 p]iod2 &1 secondly1 a simil> decrease 9 ! p]iod ( ! di/urbance takes place z ! di/urbance spreads4 ,z examples ( ^! actions ,i w quote ! foll[+4 ,! diagram ( ! di/urbance ( ,m>* #a1 #ahhb1 tak5 at ,yokohama1 %[s t ! vibrations at ! comm5cem5t ( ! di/urbance _h a p]iod ( ab\t ?ree p] second1 ne> ! middle ( ! di/urbance ! p]iod is ab\t #aa1 :il/ ne> ! end ! p]iod has decreas$ to #df4 ,t is to say1 ! backw>d & =w>d motion ( ! gr\nd at ! comm5cem5t ( ! e>?quake 0 six times z great z x 0 ne> ! end1 :5 to make "o complete oscillation x took betwe5 two & ?ree seconds4 ,probably ! p]iod became /ill less1 b 0 n record$ ow+ to ! ins5sibility ( ! in/rum5ts to su* sl[ motions4#aec ,we h n yet ! means ( comp>+ toge!r diagrams ( two or m e>?quakes1 "o hav+ be5 tak5 ne> to ! orig91 & ! o!r at a di/ance4 ,! only comp>isons :i* ,i h be5 enabl$ to make h be5 ^? ( diagrams tak5 ( ! same e>?quake1 "o 9 ,tokio & ! o!r 9 ,yokohama4 ,z ?is base is only sixte5 miles1 & ! e>?quake may h orig9at$ at a di/ance ( sev]al hundr$s ( miles1 comp>isons l ^! c be ( b little value4 ,o!r diagrams illu/rat+ ! same po9t are ^? obta9$ at ?ree /ations 9 a /raight l9e1 b at diff]5t di/ances f ! orig9 ( a di/urbance produc$ by explod+ a *>ge ( dynamite 9 a bore-hole4 ,a simple inspection ( ^! diagrams %[s t at ! ne> /ation ! di/urbance consi/$ ( backw>d & =w>d motions1 :i*1 z comp>$ ) ! same di/urbance z record$ at a m di/ant /ation1 7 v rapid4 ,fur!r1 by exam9+ ! diagram ( ! motions1 say1 at ! ne> /ation1 x is cle>ly evid5t t ! p]iod ( ! backw>d & =w>d motion rapidly decreas$ z ! motion di$ out4 ,^! illu/rations are giv5 z examples out ( a l>ge s]ies ( o!r records1 all %[+ l results4 ,an obs]vation :i* confirms ! records obta9$ f seismographs respect+ ! increase 9 p]iod ( an e>?quake z x dies out ,i h _h opportunities ( twice mak+ ) my levels4 ,aft] all p]ceptible motion ( ! gr\nd subsequ5t ^u a mod]ately sev]e %ock _h di$ away1 ,i h di/9ctly se5 ! bubble 9 "o ( ^! levels sl[ly pulsat+ ) an irregul> p]iod ( f "o to five seconds4 ,al?\gh we mu/ draw a di/9ction betwe5 e>? waves & wat] waves1 we yet see t 9 ^! po9ts !y pres5t a /rik+ lik5ess4 ,let u take1 = example1 any ( ! l>ge e>?quake waves :i* h orig9at$ (f ! coa/ ( ,s\? ,am]ica1 & !n radiat$ outw>ds1 until !y spread across ! ,pacific1 to be record$ 9 ,japan & o!r c\ntries p]haps tw5ty-five h\rs aft]w>ds1 at a di/ance ( ne>ly #i1jjj miles f _! orig94 ,ne> ?is orig9 !y appe>$ z walls ( wat] :i* 7 se5 rapidly advanc+ t[>ds ! coa/4 ,^! h be5 f tw5ty to two hundr$ feet 9 height1 & !y succe$$ ea* o!r at rapid int]vals1 until f9ally !y di$ out z a s]ies ( g5tle waves4 ,by ! "t ^! walls ( wat] trav]s$ ! ,pacific1 to1 let u say1 ,japan1 !y broad5$ out to a swell s flat t x c\ld n be detect$ on ! smoo!/ wat] except+ along %ore l9es :]e ! wat] rose & fell l ! tide4 ,in/ead ( a wall ( wat] sixty feet 9 height1 we _h long flat undulations p]haps eight feet 9 height1 b ) a di/ance f cre/ to cre/ ( f "o to two hundr$ miles4 ,if we turn to ! effects ( l>ge e>?quakes z exhibit$ on ! l&1 ,i ?9k t we %all f9d records ( ph5om5a :i* are only to be expla9$ on ! assumption ( an action hav+ tak5 place analog\s to t :i* takes place s (t5 9 ! ocean1 or an action simil> to t exhibit$ by small e>?quakes1 & artificially produc$ di/urbances1 if greatly exagg]at$4 ,! only explanation = ! ph5om5a accompany+ ! ,lisbon e>?quake appe>s to be t ! %ort quick vibrations :i* _h ru9$ s _m cities 9 ,portugal _h1 by ! "t t !y _h radiat$ to di/ant c\ntries1 gradually become *ang$ into long flat waves hav+ a p]iod ( p]haps sev]al m9utes4 ,9 c\ntries l ,engl& ^! pulse-l movem5ts 7 too g5tle to be p]ceiv$1 except 9 ! effects produc$ by tipp+ up ! b$s ( lakes & ponds4 ,! ph5om5on 0 n unlike t ( a swell produc$ by a di/ant /orm4 ,x w\ld seem possible t 9 "s cases pulsations produc+ ph5om5a l ! #8sei*es' ( ,switz]l& might h _! orig9 b5ea? ! ocean1 or deep d[n b5ea? ! e>?'s cru/4 ,p]haps1 in/ead ( comm5c+ ) ! #8snap & j>' ( an e>?quake1 !y may comm5ce z a heav+ or s9k+ ( a consid]able area1 :i* may be reg>d$ z an uncomplet$ ef=t 9 ! e/abli%m5t ( an e>?quake or a volcano4 ,f :at has n[ be5 said x w\ld seem t e>? pulsations are ph5om5a ) a real exi/5ce1 & t "s ( ^! are attributable to e>?quakes4 ,on ! o!r h&1 c]ta9 e>?quakes are attributable to e>? pulsations4 ,"s ( ! ph5om5a :i* h be5 br\ght =w>d h only a possible connection ) ^! movem5ts1 & !y yet require inve/igation4 ,ela/ic tides 9 ! e>?'s cru/ h = long be5 realities 9 ! m9ds ( physici/s4 ,^!1 h[ev]1 are due to lun> & sol> influ5ces1 & are regul> 9 _! action4 ,! tidal-l movem5ts call$ pulsations are ( great] magnitude1 & _! go+s & com+s are irregul>4 ,,*apt] ,,xxi4 ,,e>? ,,oscillations4 ,evid5ces ( oscillation--,examples ( oscillation--,temple ( ,jupit] ,s]apis--,obs]vations ( ,d>w9--,causes ( oscillation4 ,evid5ces ( oscillation4--,by e>? oscillations are meant ^? sl[ & quiet *anges 9 ! relative level ( ! sea & l& :i* geologi/s speak ( z elevations or subsid5ces4 ,^! movem5ts are especially *>act]i/ic ( volcanic & e>?quake-%ak5 c\ntries4 ,z evid5ces ( elevations we appeal to ph5om5a l rais$ bea*es1 sea-worn caves1 rais$ coral reefs1 & ! rema9s ( o!r dead organisms l b>nacles1 & ! bor+s ( li?odom\s %ells 9 & on ! rocks ( _m coa/s high above ! level ( ! highe/ tides4 ,z a pro( t subsid5ce has tak5 place1 !re is ! evid5ce af=d$ by subm]g$ =e/s1 ! prolongation ( c]ta9 valleys b5ea? ! b$ ( ! ocean1 ! =mation ( coral isl&s1 ! peculi> di/ribution ( ! plants & animals :i* we f9d 9 _m c\ntries1 & ! subm]g5ce ( works ( human con/ruction4 ,inasmu* z ^! ph5om5a are discuss$ s fully 9 _m treatises on physical geology1 ! ref]5ces to !m "h w be made z brief z possible4 ,elevations & depressions :i* h tak5 place at ! "t ( l>ge e>?quakes 9 a p>oxysmal mann] h already be5 m5tion$4 ,! movem5ts ref]r$ to 9 ?is *apt]1 al?\gh g5]ally tak+ place ) extreme sl[ness1 9 c]ta9 in/ances1 by an increase 9 _! rapidity1 h approa*$ 9 "* to e>? pulsations4 ,9 mo/ in/ances x w\ld appe> t ! upw>d movem5t ( ! gr\nd1 :i* may be lik5$ to a process ( tumefaction1 goes on s g5tly t x only becomes appreciable aft] ! lapse ( _m g5]ations4 ,examples ( movem5ts4--,lyell e/imat$ t ! av]age rate ( rise 9 ,sc&9avia has be5 ab\t two & a half feet p] c5tury4 ,at ! ,nor? ,cape ! rise may h be5 z mu* z five or six feet p] c5tury4 ,obs]vations made at ! temple ( ,jupit] ,s]apis1 betwe5 ,octob] #ahbb & ,july #ahch1 %[$ t ! gr\nd 0 s9k+ at ! rate ( ab\t "o in* 9 f\r ye>s4 ,s9ce ! ,roman p]iod1 :5 ?is temple 0 built1 ! gr\nd has sunk tw5ty feet bel[ ! waves4 ,n[ ! floor ( ! temple is on ! level ( ! sea4 ,lyell rem>ks t if we reflect on ! dates ( ! pr9cipal oscillations at ?is place !re appe>s to be connection betwe5 ! movem5ts ( upheaval & a local developm5t ( volcanic heat1 :il/ p]iods ( depression are concurr5t ) p]iods ( volcanic quiesc5ce4#aed ,z examples ( movem5ts ev5 m rapid ?an ^? at ! ,temple ( ,jupit] ,s]apis we ref] to an acc\nt ( ! e>?quakes 9 ,vallais 7,novemb] #agee71 :5 ! gr\nd ab\t a m\nta9 at a small di/ance f ,brigue sank ab\t a ?umb's-bread? e tw5ty-f\r h\rs4 ,?is took place betwe5 ,decemb] #i & ,febru>y #bf4aee ,ano!r rem>kable example ( e>? movem5t is giv5 9 ! acc\nt ( ! e>?quake at ,sc>bor\gh1 on ,decemb] #bi1 #agcg1 :5 ! head ( ! spa wat] well 0 =c$ up 9 ! air ab\t t5 y>ds high4 ,at ?is "t ! s&s on ! %ore are said to h ris5 s sl[ly t p came out to wat* !m4#aef ,two o!r examples ( rapid e>? movem5t are tak5 f ,pr(essor ,rossi's #8,meteorologia ,endog5a4' ,pr(essor ,d4 ,seghetti1 writ+ to ,pr(essor ,rossi1 says t a few lu/res ago 7"o lu/re tw5ty ye>s7 ,m\nt ,s4 ,giovanni hid ! t[ns ,j5ne & ,subiaco f ea* o!r4 ,f ,subiaco ! *ur* at ,j5ne is n[ visible1 :i* a few ye>s ago 0 invisible4 ,! p at ,j5ne also c see m ?an =m]ly4 ,! supposition is t ! side ( ,m\nt ,s4 ,giovanni is l[]$4 ,?is fact corresponds to a fact /at$ by ,pr(essor ,c>9a1 :o says t =ty or fifty ye>s ago f ,granaiola y c\ld n see ei!r ! *ur* ( ,s4 ,m>ia ,assunta di ,citrone or ! *ur* ( ,s4 ,pietro di ,cors5a4 ,n[ y c see bo?4#aeg ,= a rem>kable example illu/rat+ ! connection betwe5 seismic activity & elevation we are indebt$ to ! pati5t lab\rs ( ,d>w91 :o c>efully inve/igat$ ! evid5ces ( elevation :i* are visible ^u ! we/]n coa/s ( ,s\? ,am]ica4 ,^! evid5ces1 consi/+ ( m>ks ( erosion1 caves1 anci5t bea*es1 s& dunes1 t]races ( gravel1 c41 7 trac$ betwe5 latitudes #de #ce to #ab #e1 a di/ance nor? & s\? ( #b1jge geographical miles1 & !re is b little d\bt t !y ext5d mu* f>!r4 ,z d$uc$ f obs]vations ^u uprais$ %ells alone1 a summ>y ( ,mr4 ,d>w9's obs]vations are conta9$ 9 ! foll[+ table3-- ,feet ,at ,*iloe ! rec5t elevation has be5 #cej ,concepcion #fbe to #a1jjj ,valp>aiso #a1cjj ,coquimbo #beb ,lima #he ,%ells1 simil> to ^? cl++ to uplift$ rocks1 :i* are evid5ces ( ^! elevations1 /ill exi/ 9 ! neighb\r+ seas1 & 9 ! same proportionate numb]s z !y are f\nd 9 ! uprais$ b$s4 ,9 addition to ?is1 ,mr4 ,d>w9 %[s u t at ,lima1 dur+ ! ,indo-human p]iod1 ! elevation has be5 at lea/ eighty-five feet4 ,at ,valp>aiso1 dur+ ! la/ #bbj ye>s1 ! rise 0 ab\t n9ete5 feet1 & 9 ! sev5te5 ye>s subsequ5t to #ahag ! rise has be5 t5 or elev5 feet1 a portion only ( :i* c be attribut$ to e>?quakes4 ,9 #ahcd ! rise !re 0 app>5tly /ill 9 progress4 ,at ,*iloe !re has be5 a gradual elevation ( ab\t f\r feet 9 f\r ye>s4 ,^!1 toge!r ) num]\s o!r examples1 te/ify to ! gradual b1 z comp>$ ) o!r p>ts ( ! globe1 exce$+ly rapid rise ( ! gr\nd ^u ! we/]n %ores ( ,s\? ,am]ica4#aeh ,! mo/ important po9t to be notic$ is t ?is di/rict ( rapid elevation is "o ( ! mo/ e>?quake-%ak5 regions ( ! _w4 ,& fur!r1 judg+ f ,d>w9's rem>ks1 9 ^? portions ( x :]e ! movem5ts h be5 ! mo/ ext5sive1 & at ! same "t probably ! mo/ rapid1 ! seismic di/urbances appe> to h be5 ! mo/ noticeable4 ,simil> rem>ks may be appli$ to ,japan1 x be+ 9 ^? di/ricts :]e evid5ces ( rec5t elevation are abundant t e>?quakes are num]\s4 ,?us1 9 ! bay ( ,y$o1 :]e we h bor+s ( li?odomi 9 ! tuface\s cliffs t5 feet above high-wat] m>k1 :i*1 inasmu* z ! rock 9 :i* !y are f\nd is s(t & easily wea!r$1 indicate an exce$+ly rapid elevation1 e>?quakes are ( common occurr5ce4 ,f ! evid5ces ( elevation :i* we h ^u ! ,s\? ,am]ican coa/1 ,japan1 & 9 o!r c\ntries1 x appe>s t ^! movem5ts are int]mitt5t1 !re be+ p]iods ( re/1 :5 sea cliffs are d5ud$1 & p]haps ev5 p]iods ( subsid5ce4 ,!re is also evid5ce to %[ t1 al?\gh ^! movem5ts h be5 gradual f "t to "t1 !y h be5 aid$ by />ts occasion$ by e>?quakes4 ,z to :e!r e>?quakes are m num]\s dur+ p]iods ( elevation1 or ( subsid5ce1 or dur+ ! int]m$iate p]iods ( re/1 we h no evid5ce4 ,sudd5 displacem5ts :i* occasionally accompany e>?quakes might1 x 0 said1 sometimes be reg>d$ z ! cause ( an e>?quake1 & sometimes z ! effect4 ,! sl[ elevations "h ref]r$ to may be look$ ^u z be+ "o ( ! m important factors 9 ! production ( e>?quakes4 ,by v>i\s causes ! rocky coa/ is b5t until1 hav+ rea*$ ! limit ( its ela/icity1 x snaps1 &1 9 fly+ back l a brok5 spr+1 causes ! j>s & tremors ( an e>?quake4 ,if ?is is ! case1 !n ! numb] ( e>?quakes felt 9 a di/rict :i* is be+ elevat$ may possibly be a function ( ! rate ( elevation4 ,,app5dix4 ,,li/ ,,( ,,! ,,pr9cipal ,,books1 ,,pap]s1 ,,p]iodicals1 ,,:i* ,,are ,,ref]r$ ,,to ,,9 ,,! ,,prec$+ ,,pages4 ,= a m complete bibliography ( e>?quakes ref] to ,mallet's catalogue ( works giv5 9 8 report to ! ,briti% ,association 9 #aheh4 ,a ,true & ,p>ticul> ,relation ( ! ,dreadful ,e>?quake :i* happ5$ at ,lima1 c4 7#agdf74 #agfh4 ,abbot1 ,g54 ,h4 ,l4 ,on ! ,velocity ( ,transmission ( ,e>? ,waves4 ,am4 ,j\r4 ,sci4 ,,xv41 ,m>* #ahgh4 -- ,%ock ( ! ,explosion at ,hallet's ,po9t1 ,nov4 #ad1 #ahgf4 ,battalion ,press4 ,alex&]1 ,pr(4 ,t4 ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,am]ican ,j\rnal ( ,sci5ce4 ,annali del reale oss]vatorio meteorologico ,vesuviano4 ,annual ,regi/]1 ,!4 ,anonym\s1 ,a ,*ronological & ,hi/orical ,acc\nt ( ! mo/ ,memorable ,e>?quakes 9 ! ,_w1 c4 #agej4 -- ,a ,v9dication ( ! ,bi%op ( ,london's ,lett] occasion$ by ! ,late ,e>?quake4 #agej4 -- ,ph5om5a ( ! ,great ,e>?quake ( ,nov4 #a1 #agee4 -- ,s]i\s ,?\ghts occasion$ by ! ,late ,e>?quake at ,lisbon4 #agee4 ,asiatic ,society ( ,japan1 ,transactions (4 ,ayrton1 ,pr(4 ,w4 ,e4 ,see ,p]ry1 ,j4 ,brc5o1 ,m4 ,e/udio del ,t]remoto 7,may #ag1 #ahgi7 ,mexico4 #ahgi4 ,beke1 ,dr4 ,c4 ,t4 ,m\nt ,s9ai a ,volcano4 ,bissett1 ,rev4 ,j4 ,a ,s]mon 7on acc\nt ( ! ,e>?quake at ,lisbon1 ,nov4 #a1 #agee74 #ageg4 ,bittn]1 ,a4 ,beitrge zur ,k5ntniss des ,erdbeb5s von ,belluno vom #bi4 ,juni #ahgc4 -- ,sitzungsb4 d] ,k4 ,akad4 d4 ,wiss5s*41 lxix4 ,,ii4 ,ab?41 #ahgd4 ,bollett9o del ,vulcanismo ,italiano4 ,b\1 ,dr4 ,a4 ,ueb] das ,erdbeb5 wel*es ,mittel-,albani5 im ,octob] d4 ,j4 s s*reckli* getr(f5 hat4 ,die ,k4 ,akad4 d4 ,wiss5s*aft51 ,nov4 #ahea4 -- ,p>allele d] ,erdbeb51 des ,nordli*tes und des ,erdmagnetismus4 -- ,ueb] die ,no?w5digkeit die ,erdbeb5 und vulkanis*5 ,ers*e9ung5 g5au] als bis jetzt beoba*t5 zu lass54 ,die ,k4 ,akad4 d4 ,wiss5s*aft51 #ahea & #aheg4 ,b\gu]1 ,m4 ,( ! ,volcanoes & ,e>?quakes 9 ,p]u4 ,briti% ,association1 ,reports (4 ,brunton1 ,r4 ,h4 ,con/ructive ,art 9 ,japan4 ,trans4 ,asiatic ,soc4 ( ,japan1 ,,ii4 & ,,iii41 ,pt4 #b4 ,bryce1 ,j4 ,report to ,briti% ,association1 #ahda4 ,buff\r1 ,m4 ,! ,natural ,hi/ory ( ,e>?quakes & ,volcanoes4 ,c4 ,h4 ,a ,physical ,discussion ( ,e>?quakes1 c4 #afic4 ,cant]bury1 ,?omas1 ,"l ,ar*bi%op (1 ,! ,!ory & ,hi/ory ( ,e>?quakes4 ,cas>iego1 ,e4 ,a4 ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,cawley1 ,g4 ,"s ,rem>ks on ,con/ruction 9 ,brick & ,wood1 c4 ,trans4 ,asiatic ,soc4 ( ,japan1 ,,vi4 ,plate ii4 ,*apl91 ,pr(4 ,w4 ,s4 ,an ,exam9ation ( ! ,e>?quakes record$ at ! ,meteorological ,obs]vatory1 ,tokio4 ,trans4 ,asiatic ,soc4 ( ,japan1 ,,vi4 ,"p ii4 ,comptes ,r5dus4 ,cr$n]1 ,h4 ,das ,dippoldiswald] ,erdbeb5 vom ,oktob] #ahgg4 -- ,zeits*r4 f4 d4 ,naturwiss4 f4 ,sa*s5 u4 ,?r+54 -- ,das ,vogtlndis*-erzgebirgis*e ,erdbeb51 #bc4 ,nov4 #ahge4 -- ,zeits*r4 f4 d4 gesammt4 ,naturwiss5s*aft51 xlviii41 ,oktob]4 ,dan1 ,t4 ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,d>w91 ,*>les4 ,rese>*es on ,geology & ,natural ,hi/ory4 -- ,geological obs]vations4 ,d>w91 ,g4 ,h4 ,reports on ,lun> ,di/urbance ( ,gravity to ,briti% ,association1 #ahha4 #ahhb4 ,diff5ba*1 ,f4 ,plutonismus und ,vulkanismus 9 d] ,p]iode von #ahfh-ahgb1 und ihre ,beziehung5 zu d5 ,erdbeb5 im ,rhe+ebiet4 ,doelt]1 ,c4 von4 ,ueb] die ,eruptivgebilde von ,fleims1 neb/ e9ig5 ,bem]kung5 b] d5 ,bau lt]] ,vulcane4 -- lxxiv4 ,b& d4 ,sitzungsb4 d4 ,k4 ,akad4 d4 ,wiss5s*41 ,i4 ,ab?41 ,dec4 ,heft1 ,jahrg4 #ahgf4 ,doolittle1 ,rev4 ,t4 ,e>?quakes ,expla9$ & ,practically ,improv$1 c4 #afic4 ,doyle1 ,p4 ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,em]son1 ,pr(41 ,b4,a4 ,review ( ,von ,seeba*s' ,e>?quake ( ,m>* #f1 #ahgb4 ,am4 ,j\r4 ,sci41 ,s]ies ,,iii4 ,ew+1 ,pr(4 ,j4 ,a4 ,e>?quake ,measurem5t4 ,a memoir publi%$ by ! ,tokio ,univ]sity4 #ahhc4 -- ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,falb1 ,r4 ,g$ank5 und ,/udi5 b] d5 ,vulkanismus1 c4 #ahge4 -- ,grundzge zu e9] ,!orie d] ,erdbeb5 und ,vulkanausbr*e4 -- ,das ,erdbeb5 von ,belluno4 #8,sirius1' ,bd4 ,,vi41 ,heft ii4 ,flam/ead1 ,j4 ,a ,lett] conc]n+ ,e>?quakes4 #afic4 ,=el1 ,f4 ,a4 ,les ,tremblem5ts de ,t]re 7,suisse74 ,ar*4 des ,sci5ces ,physiques et ,naturelles1 ,,vi4 p4 #dfa4 -- ,tremblem5t de ,t]re du #cj ,dcembre #ahgi4 ,fu*s1 ,k>l4 ,vulkane und ,erdbeb54 -- ,die ,vulkanis*5 ,ers*e9ung5 d] ,erde4 ,g>cia1 ,j4 ,c4 ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,ge9itz1 ,dr4 ,e4 ,das ,erdbeb5 von ,iquique am #i4 ,mai #ahgg1 c4 ,die ,k4 ,leop4-,c>ol4-,deuts*5 ,akademie d] ,natur=s*]1 ,b& xl41 ,nr4 #i4 ,g5tleman's ,magaz9e1 ,!4 ,geographical ,society1 ,proce$+s (4 ,geological ,society1 ,proce$+s (4 ,gir>d1 ,dr4 ,h4 ,ueb] ,erdbeb5 und ,vulkane4 #ahde4 ,gray1 ,t4 ,see ,trans4 ,seis4 ,soc4 ( ,japan4 -- ,on ,in/rum5ts = ,measur+ & ,record+ ,e>?quake ,motions4 ,phil4 ,mag4 ,sept4 #ahha4 -- ,on ,rec5t ,e>?quake ,inve/igation4 ,! ,*rysan!mum1 #ahha4 ,guisc>di1 ,pr(4 ,g4 ,notizie del ,vesuvio4 #aheg4 -- ,il t]remoto di ,casamicciola del #d ,m>zo4 #ahha4 ,hales1 ,s41 ,d4,d41 ,f4,r4,s4 ,"s ,consid]ations on ! ,causes ( ,e>?quakes4 #agej4 ,hamilton1 ,sir ,w4 ,obs]vations on ,m\nt ,vesuvius1 ,m\nt ,etna1 c4 #aggd4 ,hattori1 ,i4 ,de/ructive ,e>?quakes 9 ,japan4 ,trans4 ,asiatic ,soc4 ( ,japan1 ,v4 ,plate i4 ,heim1 ,pr(4 ,a4 ,les ,tremblem5ts de ,t]re et leur ,etude ,sci5tifique4 #ahhj4 -- ,pr(4 ,a4 ,die ,s*weiz]is*5 ,erdbeb5 9 #ahha-ahhb4 ,hoeff]1 ,pr(4 ,h4 ,die ,erdbeb5 ,krnt5s und d]5 ,/ossl9i54 ,die ,kais4 ,akademie d4 ,wiss5s*aft51 ,b& xlii4 ,hf]1 ,pr(4 ,h4 ,das ,erdbeb5 von ,belluno1 am #bi4 ,juni #ahgc4 ,sitzungsb4 d] ,k4 ,akad4 d4 ,wiss5s*41 ,i4 ,ab?41 ,b& lxxiv4 ,h(f1 ,k4 ,e4 ,a4 von4 ,ges*i*te d] dur* ,ueb]lief]ung na*gewies55 natrli*5 ,v]nd]ung5 d] ,erdob]fl*e4 #ahbb4 ,hooke1 ,r41 ,m4,d41 ,f4,r4,s4 ,disc\rses conc]n+ ,e>?quakes4 ,hopk9s1 ,william4 ,report to ! ,briti% ,association on ! ,geological ,!ories ( ,elevation & ,e>?quakes4 #ahdg4 ,horton1 ,rev4 ,mr4 ,an ,acc\nt ( ! ,e>?quake :i* happ5$ at ,leghorn 9 ,italy 7,jan4 #agdb74 #agej4 ,humboldt1 ,alex&] von4 ,cosmos4 -- ,travels4 ,jeitteles1 ,l4 ,a4 ,b]i*t b] das ,erdbeb5 am #ae4 ,janu> #aheh4 -- ,sitzungsb]i*te d] ma!m4-naturw4 ,classe d4 ,k4 ,akad4 d4 ,wiss5s*41 xxxv4 ,s4 #eaa4 ,judd1 ,j4 ,w41 ,pr(4 ,volcanoes1 ,:at !y ,are & ,:at !y ,tea*4 ,knipp+1 ,e4 ,v]zei*niss von ,erdbeb5 wahrg5omm5 9 ,tokio1 c4 ,mitt4 d4 ,deuts*4 ,gesells*4 fr ,natur- und ,vlk]kunde ,o/asi5s1 ,heft #ad4 -- ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,lasaulx1 ,a4 von4 ,das ,erdbeb5 von ,h]zog5ra? am #bb4 ,octob] #ahgc4 ,lem]y1 ,m4 ,a ,physico-,*emical ,explanation ( ,subt]ranean ,fires1 ,e>?quakes1 c4 ,lescasse1 ,m4 ,j4 ,etude sur les ,con/ructions ,japonaises1 c4 ,mmoires de la ,socit des ,+nieurs ,civils4 ,li/]1 ,m41 ,m4,d41 ,f4,r4,s4 ,( ! ,nature ( ,e>?quakes4 ,little1 ,rev4 ,j4 ,conjectures on ! ,physical ,causes ( ,e>?quakes & ,volcanoes4 #ahbj4 ,mallet1 ,r4 ,! ,neapolitan ,e>?quake1 ,vol4 ,,ii4 ,reports to ! ,briti% ,association1 #ahej1 #ahea1 #aheb1 #ahed1 #aheh1 #ahfa4 -- ,second>y ,effects ( ! ,e>?quake ( ,ca*>4 ,proc4 ,geolog4 ,soc41 #ahgb4 -- ,dynamics ( ,e>?quakes4 ,trans4 ,royal ,iri% ,acad4 #ahdf4 ,milne1 ,david4 ,reports to ,briti% ,association1 #ahda1 #ahdc1 #ahdd4 ,milne1 ,john4 ,see ,trans4 ,seis4 ,soc4 ( ,japan4 -- ,on ,seismic ,exp]im5ts 7) ,t4 ,gray1 ,b4,sc41 ,f4,r4,s4,e47 ,trans4 ,royal ,soc4 #ahhb4 -- ,on ,seismic ,exp]im5ts 7) ,t4 ,gray1 ,b4,sc41 ,f4,r4,s4,e47 ,proc4 ,royal ,soc4 ,no4 #bag1 #ahha4 -- ,e>?quake ,obs]vations & ,exp]im5ts 9 ,japan 7) ,t4 ,gray1 ,b4,sc41 ,f4,r4,s4,e47 ,phil4 ,mag41 ,nov4 #ahha4 -- ,on ! ,ela/icity & ,/r5g? ,con/ants ( c]ta9 ,rocks 7) ,t4 ,gray1 ,b4,sc41 ,f4,r4,s4,e47 ,j\r4 ,geolog4 ,soc41 #ahhb4 -- ,a ,visit to ! ,volcano ( ,o%ima4 ,geolog4 ,mag41 ,dec4 #b1 ,vol4 ,,iv41 pp4 #aic-aig1 #bee4 -- ,on ! ,=m ( ,volcanoes4 ,geolog4 ,mag41 ,dec4 #b1 ,vol4 ,v41 & ,dec4 #b1 ,vol4 ,,vi4 -- ,note ^u ! ,cool+ ( ! ,e>?1 c4 ,geolog4 ,mag41 ,dec4 #b41 ,vol4 ,,vii41 p4 #ii4 -- ,inve/igation ( ! ,e>?quake ,ph5om5a ( ,japan4 ,rep4 ,brit4 ,assoc41 #ahha & #ahhb4 -- ,a ,l>ge ,crat]4 ,popul> ,sci5ce ,review4 -- ,! ,volcanoes ( ,japan 7a s]ies ( ,articles74 ,japan ,gazette4 -- ,e>?quake ,lit]ature ( ,japan 7a s]ies ( ,articles74 ,japan ,gazette4 -- ,! ,e>?quake ( ,dec4 #bc1 #ahhj4 ,! ,*rysan!mum1 #ahha4 -- ,e>?quake ,motion4 ,! ,*rysan!mum1 #ahhb4 -- ,seismology 9 ,japan4 ,nature1 ,oct4 #ahhb4 -- ,e>? ,movem5ts4 ,! ,times1 ,oct4 #ab1 #ahhb4 ,mit*ell1 ,rev4 ,j4 ,conjectures ,conc]n+ ! ,cause & ,obs]vations ^u ! ,ph5om5a ( ,e>?quakes4 #agfj4 ,mohr1 ,dr4 ,f4 ,ges*i*te d] ,erde4 #ahge4 ,naturkundig ,tijds*rift voor ,n$]l&s* ,indie4 #ahge-ahhj4 ,naumann1 ,dr4 ,e4 ,ueb] ,erdbeb5 und ,vulkanausbr*e 9 ,japan4 ,mitt4 d4 ,deuts*4 ,gesells*4 fr ,natur- und ,vlk]kunde ,o/asi5s4 ,heft #ae4 ,nogg]a?1 ,dr4 ,j4 ,die ,erdbeb5 vom #bi4 ,juli #ahdf im ,rhe+ebiet1 c4 -- ,die ,erdbeb5 im ,visp?ale 7#ahee74 -- ,die ,erdbeb5 im ,rhe+ebiet 9 d5 ,jahr5 #ahfh1 #ahfi1 #ahgj4 -- ,jahrgnge d4 ,v]b&lung5 d4 ,natur4 ,v]e9s fr #ahgj4 ,rhe9l& u4 ,we/phal51 xxvii4 ,oldham1 ,dr4 ,second>y ,effects ( ! ,e>?quake ( ,ca*as4 ,proc4 ,geolog4 ,soc4 #ahgb4 -- ,!rmal ,spr+s ( ,india4 ,memoirs ( ,geolog4 ,survey ( ,india1 ,,xix4 ,plate #b4 -- ,a ,catalogue ( ,indian ,e>?quakes4 ,memoirs ( ,geolog4 ,survey ( ,india1 ,,xix4 ,plate #c4 -- ,! ,ca*as ,e>?quake4 ,memoirs ( ,geolog4 ,survey ( ,india1 ,,xix4 ,plate #a4 ,palm]1 ,col4 ,h4 ,s4 ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,palmi]i1 ,pr(4 ,l41 e ,scac*i1 ,a4 ,della ,regione ,volcanica del ,monte ,vulture1 e del ,tremuoto ivi avv5uto nel d #ad ,ago/o #ahea1 #aheb4 -- ,annali del reale ,oss]vatorio ,meteorologico ,vesuviano4 -- ,il ,vesuvio1 il ,t]remoto d' ,is]nia e l'eruzione sottom>9a di ,santor9o4 ,r4 ,accad4 d4 ,sci4 ,fis4 e ,mat4 di ,napoli1 iv4 #ahff4 -- ,sul rec5te ,t]remoto di ,corleone4 ,r4 ,accad4 d4 ,sci4 ,fis4 e ,mat41 v4 #ahgf4 -- ,il ,t]remoto di ,scio del d #d ,aprile4 ,r4 ,accad4 d4 ,sci4 ,fis4 e ,mat4 di ,napoli1 v4 #ahha4 -- ,sul ,t]remoto di ,casamicciola del #d ,m>zo #ahha4 ,r4 ,accad4 d4 ,sci4 ,fis4 e4 ,mat4 di ,napoli4 #ahha4 ,paul1 ,pr(4 ,h4 ,m4 ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,p]rey1 ,pr(4 ,a4 ,e>?quake ,catalogue & ,memoirs4 7,= li/ see ,mallet's ,report to ,briti% ,association4 #aheh47 -- ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,p]ry1 ,j41 & ,w4 ,e4 ,ayrton4 ,on a ,neglect$ ,pr9ciple t may be ,employ$ 9 ,e>?quake ,measurem5t4 -- ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,philosophical ,magaz9e4 ,pick]+1 ,rev4 ,r4 ,an ,address to ^? :o h ei!r retir$ or int5d to leave ,t[n "u ! ,imag9>y ,appreh5sion ( ! ,approa*+ ,%ock ( ano!r ,e>?quake4 #agej4 ,ray1 ,j41 ,f4,r4,s4 ,a ,summ>y ( ! ,causes ( ! ,alt]ations :i* h happ5$ to ! ,face ( ! ,e>?4 ,rock/roh1 ,e4 ,in=me de la ,comision ,ci5tfica del ,in/ituto ,nacional de ,guatemala1 nombrada por el ,sr4 ,m9i/ro de ,in/ruccion ,pblica p>a el ,e/udio de los ,f5m5os ,volcnicos en el ,lago de ,ilopango4 #ahhj4 ,rockwood1 ,pr(4 ,c4 ,g4 ,notes on ,e>?quakes4 ,annually 9 ! ,am4 ,j\r4 ,sci4 -- ,japanese ,seismology4 ,am4 ,j\r4 ,sci41 ,,xxii4 ,dec4 #ahha4 ,roma9e1 ,w4 ,a ,disc\rse occasion$ by ! ,late ,e>?quake4 #agee4 ,rossi1 ,pr(4 ,m4 ,s4 di4 ,intorno all' odi]na fase dei ,t]remoti 9 ,italia1 e segnatam5te sul ,t]remoto 9 ,casamicciola del #d ,m>zo #ahha4 ,societ ,geografica ,italiana4 #ahha4 -- ,la ,meteorologia ,endog5a1 #b vols4 ,royal ,society1 ,transactions (4 ,scac*i1 ,a4 ,see ,palmi]i4 ,s*midt1 ,dr4 ,j4 ,f4 ,unt]su*ung5 b] das ,erdbeb5 am #ae4 ,janu> #aheh4 -- ,/udi5 b] ,erdbeb54 #ahgi4 -- ,die ,eruption des ,vesuv 7#ahee74 #ahef4 ,scrope1 ,g4 ,p4 ,volcanoes4 ,seeba*4 ,das mittle ,deuts*e ,erdbeb5 7#ahgb74 ,mitt4 d] ,k4,k4 geograph4 ,gesells*41 ,,ii4 ,jahrg41 #b4 ,heft1 #ahgc4 ,s]pi]i1 ,pr(4 ,a4 ,c4 ,s4 ,nuove ,oss]vazioni sul ,t]remoto avv5uto 9 ,italia il #ab ,m>zo #ahgc4 ,i/ituto ,lomb>do4 #ahgc4 -- ,il ,t]remoto di ,rim9i della notte #ag-ah ,m>zo #ahge4 -- ,docum5ti nuove e ,riflessioni sul ,t]remoto della notte #ag-ah ,m>zo #ahge4 ,meteorologia ,italiana1 iv4 #ahge4 -- ,det]m9azione delle fasi e delle leggi del gr&e ,t]remoto avv5uto 9 ,italia nella notte #ag-ah ,m>zo #ahge4 ,i/ituto ,lomb>do4 #ahge4 -- ,dell' influ5za del ,lume ,sol>e sui ,t]remoti4 ,i/ituto ,lomb>do4 #ahhb4 ,%]lock1 ,t41 ,d4,d4 7,"l ,bi%op ( ,london74 ,a ,lett] on ! occasion ( ! late ,e>?quakes4 #agej4 ,%[]1 ,rev4 ,j41 ,d4,d4 ,practical ,reflections on ! ,e>?quakes t h happ5$ 9 ,europe & ,am]ica1 c4 #agej4 ,/bel1 ,a4 7see ,reiss1 ,w47 ,/ukeley1 ,rev4 ,w41 ,m4,d41 ,f4,r4,s4 ,! ,philosophy ( ,e>?quakes1 ,natural & ,religi\s1 c4 ,plates #a1 #b1 & #c4 #agef4 ,/urmius1 ,j4 ,c4 ,a ,me?odical ,acc\nt ( ,e>?quakes4 ,suess1 ,e4 ,die ,erdbeb5 ,ni$]/]rei*es4 ,die ,kais4 ,akademie d] ,wiss5s*aft51 ,bd4 xxxiii4 -- ,die ,erdbeb5 des sdli*5 ,itali5s4 ,die ,kais4 ,akademie d] ,wiss5s*aft51 ,bd4 xxxiv4 ,volg]1 ,dr4 ,g4 ,h4 ,unt]su*ung5 b] das ,phnom5 d] ,erdbeb54 #aheg4 ,wag5]1 ,dr4 ,g4 ,bem]kung5 b] ,erdbeb5mess] und ,vors*lge zu e9em neu5 ,in/rum5te dies] ,art4 ,mitt4 d4 ,deuts*4 ,gesells*4 fr ,natur- und ,vlk]kunde ,o/asi5s1 ,heft #ae4 -- ,see ,trans4 ,seis4 ,soc4 ( ,japan4 ,w9*ilsea1 ,! ,e>l (4 ,a ,true & ,exact ,relation ( ! late ,prodigi\s ,e>?quake & ,eruption ( ,m\nt ,etna4 #affi4 ,woodw>d1 ,j41 ,m4,d41 ,f4,r4,s4 ,e>?quake caus$ by "s ,accid5tal ,ob/ruction ( a ,cont9ual ,subt]ranean ,heat4 ,,seismological ,,society ,,( ,,japan4 ,! foll[+ are a li/ ( ! pap]s publi%$ by ?is ,society3-- ,,vol4 ,i4 ,milne1 ,j4 ,seismic ,sci5ce 9 ,japan4 #ce pages4 ,ew+1 ,j4 ,a4 ,new ,=m ( ,p5dulum ,seismograph4 #f pages1 #c plates4 ,gray1 ,t4 ,seismomet] & ,torsion ,p5dulum ,seismograph4 #h pages1 #b plates4 ,m5d5hall1 ,t4 ,c4 ,accel]ation ( ,gravity at ,tokio 7ab/ract74 #b pages4 ,wag5]1 ,g41 & ,e4 ,knipp+4 ,new ,seismomet] & ,obs]vations ) same4 #ah pages1 #a plate4 ,milne1 ,j4 ,e>?quake 9 ,japan ( ,feb4 #bb1 #ahhj4 #aaf pages1 #e plates1 #h woodcuts4 ,,vol4 ,,ii4 ,milne1 ,j4 ,rec5t ,e>?quakes ( ,y$do1 ,effects on ,build+s1 c4 #ch pages1 #b plates1 & _m tables4 ,m5d5hall1 ,t4 ,c4 ,gravity on ,summit ( ,fujiyama 7ab/ract74 #b pages4 ,paul1 ,h4 ,m4 ,e>? ,vibrations f ,railroad ,tra9s 7ab/ract74 #d pages4 ,ew+1 ,j4 ,a4 ,a/atic ,horizontal ,lev] ,seismograph 7ab/ract74 #e pages1 #a plate4 ,milne1 ,j4 ,p]uvian ,e>?quake ( ,may1 #i1 #ahgg4 #dg pages1 #b plates1 tables4 ,con/itution1 ,rules1 ,(fic]s & ,memb]s ( ! ,society1 ,dec41 #ahha4 ,,vol4 ,,iii4 ,gray1 ,t4 ,/eady ,po9ts = ,e>?quake ,measurem5ts4 #aa pages1 #c plates4 ,milne1 ,j4 ,exp]im5ts 9 ,obs]vational ,seismology4 #ec pages1 #a plate1 tables4 -- ,! ,great ,e>?quakes ( ,japan4 #ch pages1 #a plate1 _m tables4 ,p]ry1 ,j4 ,!ory ( a ,rock+ ,column4 #d pages4 ,knipp+1 ,e4 ,e>?quake ( ,july #be1 #ahhj1 ) ,dr4 ,wag5]'s ,seismomet]4 #d pages4 ,ew+1 ,j4 ,a4 ,e>?quake ,obs]vation at ?ree or m ,/ations1 c4 #d pages4 -- ,records ( ?ree rec5t ,e>?quakes4 #f pages1 #c plates4 -- ,e>?quake ( ,m>* #h1 #ahha4 #h pages1 #a plate4 ,milne1 ,j4 ,horizontal & ,v]tical ,motion 9 ,e>?quake ( ,m>* #h1 #ahha4 #h pages1 #c plates4 ,gray1 ,t4 ,seismograph = ,regi/]+ ,v]tical ,motion4 #c pages1 #a plate4 ,ew+1 ,j4 ,a4 ,seismomet] = ,v]tical ,motion4 #c pages1 #a plate4 ,gray1 ,t4 ,seismograph = ,l>ge ,motions4 #b pages4 -- ,comp5sat+ a ,p5dulum to make x ,a/atic4 #c pages4 ,palm]1 ,h4 ,s4 ,note on ,e>? ,vibrations4 #c pages4 ,kuwab>a1 ,m4 ,! ,hot ,spr+s ( ,atami4 #b pages4 ,,vol4 ,,iv4 ,milne1 ,j4 ,di/ribution ( ,seismic ,activity 9 ,japan4 #cj pages1 #a plate4 ,wada1 ,t4 ,notes on ,fujiyama4 #g pages4 ,cas>iego1 ,e4 ,abella y4 ,e>?quakes ( ,nueva ,vizcaya 9 #ahha4 #bc pages1 #b maps4 ,milne1 ,j4 ,utilisation ( ,e>?'s ,int]nal ,heat4 #ab pages4 ,ew+1 ,j4 ,a4 ,e>?quake ( ,m>* #aa1 #ahhb4 #e pages4 ,doyle1 ,p4 ,note on an ,indian ,e>?quake4 #f pages4 ,milne1 ,j4 ,sy/ematic ,obs]vation ( ,e>?quakes4 #ca pages1 #e plates4 ,,vol4 ,v4 ,naumann1 ,dr4 ,e4 ,notes on ,secul> ,*anges ( ,magnetic ,decl9ation 9 ,japan1 p4 #a-ah4 ,cas>iego1 ,don ,e4 ,abella y4 ,monografa ,geolgica del ,volcan de ,albay ,el ,myon4 p4 #ai-dc4 ,g>cia1 ,don ,j4 ,c5t5o y4 ,ab/ract ( a ,memoir on ! ,e>?quakes on ! ,isl& ( ,luzon 9 #ahhj4 p4 #dc-hi4 ,ew+1 ,pr(4 ,j4 ,a4 ,seismological ,notes4 -- ,a ,duplex ,p5dulum ,seismomet]4 -- ,! ,susp5sion ( a ,horizontal ,p5dulum4 -- ,a ,spe$ ,gov]nor = ,seismograph ,clocks1 p4 #hi-ie4 ,dan1 ,t41 ,s4,b4 ,notes on ! ,e>?quake at ,atami1 9 ! ,prov9ce ( ,idzu1 on ,septemb] #bi1 #ahhb4 p4 #ie-aje4 ,,vol4 ,,vi4 ,alex&]1 ,pr(4 ,t4 ,! ,developm5t ( ! ,record giv5 by a ,bracket ,ma*9e4 ,milne1 ,j4 ,e>? ,pulsations4 ,ew+1 ,j4 ,a4 ,note on a ,duplex ,p5dulum ) a ,s+le ,bob4 ,g]g5s1 ,f4 ,note on an ,iron ,ca/+1 ,suppos$ to h be5 ,di/urb$ :il/ ,cool+ by an ,e>?quake4 ,we/1 ,c4 ,d4 ,on a ,p>allel ,motion ,seismograph4 ,ew+1 ,j4 ,a4 ,c]ta9 ,me?ods ( ,a/atic ,susp5sion4 ,alex&]1 ,t4 ,ball & ,cup ,seismomet]4 ,knipp+1 ,messrs4 ,paul &4 ,report on a ,sy/em = ,e>?quake ,obs]vation4 ,catalogues ( ,e>?quakes4 ,,index4 ,abbadie1 ,m4 d'1 on e>? tremors1 #cji ,abbot1 ,g5]al ,h4 ,l41 on ! transmission ( vibrations1 #fb ,abella1 ,m41 on ! e>?quake 9 ! ,philipp9es 9 #ahha1 #gg ,activity1 on seismic1 #f ,ari/otle1 on ! classification ( e>?quakes1 #da ,artificial e>?quakes1 exp]im5ts on1 #eg -- -- int5sity (1 #fa ,aurora1 on ! occurr5ce (1 ) e>?quakes1 #bfd ,ayrton & ,p]ry1 on ! effect ( s(t f\ndations1 #acj -- -- on ! p]iod ( vibration ( build+s1 #aae -- -- on ! pr9ciple (1 #ca ,b>omet]1 effect ( *anges (1 on e>?quakes1 #bff ,b]telli1 on aurora & e>?quakes1 #bfe -- on e>? tremors1 #caf1 #cbj -- on ! normal tromomet] (1 #cag ,bittn]1 ,a41 on ! build+s ( ,belluno1 #ajj ,bridges1 on e>?quake1 #adj ,brunton1 ,r4 ,h41 on build+s 9 e>?quake c\ntries1 #abc ,buckle1 on ! hi/ory ( civilisation1 #a ,build]s1 int]e/ ( ! /udy ( e>?quakes to1 #c ,build+s1 on cracks 91 #ih1 #ajh -- ! effect ( e>?quakes on1 #if -- on ! irregul> de/ruction (1 #if -- -- effect on ! end h\se 9 a r[1 #aab -- -- *ur* ( ,/4 ,augu/9 at ,manilla1 #aac -- -- relation ( de/ruction (1 to e>?quake motion1 #ajc -- -- protection (1 #adc -- -- pit* ( ! ro( (1 #aaj -- -- position ( op5+s 9 ! walls (1 #aaa -- -- sw+ (1 #aae -- -- p]iod ( vibration (1 #aae -- -- pr9ciple ( relative p]iods 91 #aaf -- -- types (1 = e>?quake c\ntries1 #aba -- -- effect ( und]ly+ rocks on1 #acj -- g5]al conclusions reg>d+1 #add ,cacciatore1 def9ition ( !1 #ah ,caldcleugh1 ,a41 on e>?quake frequ5cy1 #bde -- on b>ometric height & e>?quakes1 #bff ,c>ru!rs1 ,j41 on e>?quakes & tides1 #bia ,c5trum1 def9ition (1 #i -- on ! dep? (1 #bac -- on ! maximum dep? (1 #bah ,c5trum1 det]m9ation ( position (1 see orig9s ,*apl91 ,w4 ,s41 on ! bracket seismomet] (1 #bg -- on e>?quakes & ! position ( ! moon1 #beb ,coa/ l9e1 on ! movem5t (1 #afj ,cocks1 ,r41 on e>?quakes & tides1 #bij ,coseismic l9es1 def9ition (1 #aj ,curves1 on microseismic1 #cba ,d>w91 ,*>les1 on ! movem5t ( coa/ l9es1 #afj -- ,george ,h41 on e>? tides1 #bhe -- on tidal loads1 #bia -- on e>? pulsation1 #ccj -- on ! effect ( fluctuations ( b>ometric pressure1 #ccf -- exp]im5ts at ,cambridge1 #caj ,delauney1 ,m4 ,j41 on ! influ5ce ( ! planets on e>?quakes1 #bfa ,diagonic1 def9ition (1 #aa ,dia/rophic1 def9ition (1 #aa ,direction ( motion1 f in/rum5tal records1 #aih ,di/ribution1 on e>?quake1 #bbf -- examples (1 #bca ,di/urbance1 on ! propagation (1 #ej ,d\glas1 ,j41 on ,s\? ,am]ican h\ses1 #abf ,e>? p>ticle1 on ! velocity & accel]ation (1 #gi ,e>?quake motion1 nature (1 z d$uc$ f ! feel+s1 #fg -- direction (1 d]iv$ f in/rum5tal records1 #fi -- duration (1 #ga -- p]iod ( vibration 91 #gd -- examples ( ext5t (1 #ge-gg -- absolute int5sity ( =ce 91 #hc -- radiation (1 #he -- velocity ( propagation (1 #hg ,e>?quake at ,lisbon1 velocity ( propagation (1 #hh ,e>?quakes1 g5]al examples ( effects (1 #adb -- geological *anges produc$ by1 #afa -- hunt+1 #ahg -- di/ribution (1 #bbf -- maps1 #ahi -- second>y1 #bdh -- table (1 = n9ete5? c5tury1 #bei -- on ! c\rse (1 #bgg-bha -- & tides1 #bij -- pr$iction (1 #big-cjd ,ela/ic waves1 nature (1 #dd ,em]g5ce1 angle (1 #i ,en]gy1 dissipation (1 9 e>?quakes1 #eb -- seismic1 9 relation to geological "t1 #bcd -- -- table (1 #bdj ,epic5trum1 def9ition (1 #i ,eu?utropic1 def9ition (1 #aa ,ew+1 ,j4 ,a41 p5dulum seismograph (1 #be -- a/atic p5dulum (1 #bf -- bracket seismograph (1 #bf ,falb1 ,r41 on ! influ5ce ( ! sun & moon on e>?quakes1 #bhf ,fissures1 on ! mat]ial dis*>g$ f1 #adh -- on ! explanation (1 #aea ,focal cavity1 def9ition (1 #i -- on ! =m (1 #bba ,=bes1 ,d41 on an e>?quake 9 ,m5doza1 #aea ,frequ5cy ( e>?quakes1 #bdc ,fr]e1 ,sir ,h4 ,b>tle1 on geological *anges produc$ by e>?quakes1 #afa ,fu*s1 on sea waves1 #agf -- on ! movem5t ( ! seismic c5tre1 #bcc -- on e>?quakes & volcanic outbur/s1 #bga -- on hot spr+s1 #aeg ,fum>oles1 ! effect ( e>?quakes on1 #aef ,ge9itz1 ,dr41 on sea waves1 #ahb ,geologi/s1 on ! int]e/ ( seismology to1 #b ,gray1 ,t41 a/atic p5dulum (1 #bf -- bracket seismomet] (1 #bg -- conical p5dulum (1 #bi -- dead heat p5dulum (1 #bb -- on ! rotation ( bodies1 #aif -- roll+ sph]es & cyl9d]s (1 #bi -- torsion p5dulum seismomet] (1 #be -- v]tical motion seismomet]s (1 #cb1 #cc -- & ,milne1 seismograph (1 #ch ,hattori1 ,i41 on ! l>ge e>?quakes ( ,japan1 #bdd ,haughton1 ,pr(41 li/ ( active volcanoes (1 #bbg -- me?od ( f9d+ e>?quake orig9s (1 #bji ,hills1 on ! want ( support on ! face (1 #acf ,hf]1 on an e>?quake at ,belluno1 #bbe ,h(fmann1 ,f41 on ! b>omet] & e>?quakes1 #bfg ,hooke1 on e>?quake motion1 #db ,hopk9s1 on ! ?ickness ( ! e>?'s cru/1 #bhd ,humboldt1 on meteors & e>?quakes1 #bfa -- on ! b>omet] & e>?quakes1 #bfg -- on volcanoes & e>?quakes1 #bgi ,imag9ation1 effect ( e>?quakes on !1 #b ,in/rum5ts1 direction ( motion d]iv$ f1 #aih ,int5sity1 on e>?quake1 #ea1 #ga -- seismic curve (1 = ,kioto1 #bdb ,isoseismic circles1 def9ition (1 #aj -- areas1 def9ition (1 #aj ,kluge1 on sea waves1 #age -- on e>?quake frequ5cy1 #bdf -- on simultane\s e>?quakes1 #bdh -- on e>?quakes & sun spots1 #bfc -- on e>? pulsations1 #cci ,kreil1 p5dulum seismomet] (1 #be ,lakes1 on di/urbances 91 #aed ,l&1 effect ( e>?quakes on1 #adf-afb -- on ! reason ( movem5ts (1 #afb -- on cracks & fissures =m$ 91 #adf ,level1 on ! use ( = e>? pulsations1 #cbh ,lit]ature1 on seismic1 #f -- on ,japanese e>?quake1 #g ,mallet1 ,r41 on area ( di/urbance z a te/ ( seismic en]gy1 #gh -- on clock /opp+1 #cf -- li/ ( works on e>?quakes (1 #e -- curve ( seismic en]gy (1 #bch -- def9ition ( e>?quake (1 #dc -- on e>?quake frequ5cy1 #bdc -- on ! influ5ce ( ! heav5ly bodies on e>?quakes1 #bec -- on maximum dep? ( orig91 #bah -- on p5dulum seismomet]s1 #bj -- projection seismomet] (1 #ag -- on ! ,neapolitan e>?quake1 #fi1 #gg1 #hc1 #ig1 #ajc1 #acb1 #adb1 #bah1 #bhj -- on sea waves1 #agj -- on ! sw+ ( m\nta9s1 #ace -- on propagation f a fissure1 #bag ,mallet on ! temp]ature ( focal cavity1 #hd ,malvasia1 ,m4 le ,conte1 on e>? tremors1 #caf ,m>t91 ,d4 ,s41 on ! ,new ,engl& e>?quake ( #ahgd1 #adb ,meizoseismic area1 def9ition (1 #aj ,melzi1 on curves ( microseismic motion1 #cbb ,meteors1 on e>?quakes &1 #bfj ,microseismic movem5ts1 on cause (1 #cbd ,milne1 ,d41 on ! ,lisbon e>?quake1 #hg -- on e>?quake syn*ronism1 #bdg ,mit*ell1 on e>?quake motion1 #db ,moon1 effect (1 on e>?quakes1 #bea1 #bhe ,m\nta9s1 on ! sw+ (1 #ace ,naumann1 ,e41 on meteors & e>?quakes1 #bfa -- on sun spots & e>?quakes1 #bfc ,ocean1 on di/urbances 91 #afc-ahf ,orig91 def9ition (1 #i -- on ! det]m9ation (1 #ahg -- position (1 d$uc$ f direction ( motion1 #aib -- -- f de/ruction ( build+s1 #aid -- -- f rotation ( bodies1 #aie -- -- f "t ( occurr5ce1 #aii -- -- examples ( me?ods ( calculat+1 #bjj-bab ,oscillations1 on e>?1 #cdd ,ov]turn+ mom5t1 on ! area ( greate/1 #ec ,palm]1 ,col4 ,h4 ,s41 on e>? tremors1 #cjg ,palmi]i1 on clock /opp+1 #cf1 #fb ,paul1 ,h4 ,m41 on e>? tremors1 #cjh ,p]rey1 ,a41 on ! influ5ce ( ! moon on e>?quakes1 #bea ,p]rey on ! p]iodicity ( e>?quakes1 #h ,p]ry1 ,j41 on position ( op5+s 9 walls1 #aaa ,physici/s1 on ! int]e/ ( e>?quakes to1 #b ,planets1 influ5ce (1 on e>?quakes1 #bfj ,plantam\r1 ,m41 on e>? pulsations1 #cbh ,plei/osei/s1 def9ition (1 #aj ,poly1 ,m4 ,a41 on e>?quakes & sun spots1 #bfc -- on e>?quakes & revolv+ /orms1 #bid ,pro/1 ,m4 le ,b>on1 on e>? tremors1 #caf ,pulsation1 on e>?1 #d1 #cbf-cdc ,records1 on receiv]s (1 #cc ,riv]s1 on di/urbances 91 #aed ,rockwood1 ,pr(41 on ,am]ican e>?quakes1 #f ,ronaldson1 ,t41 on ,san ,francisco h\ses1 #abi ,rossi1 ,m4 ,s4 di1 on an eruption ( gas 9 ! ,tib]1 #aec -- aurora & e>?quakes1 #bfd -- e>? tremors1 #cag1 #cbj -- e>? oscillations1 #cdf -- e>? pulsations1 #cbg -- microseismograph (1 #cah -- microphonic obs]vations (1 #cai1 #cbc -- normal tromomet] (1 #cag ,s*midt1 on ! influ5ce ( b>ometric pressure on e>?quakes1 #bfg ,sea waves1 on nature (1 #afe -- on cause (1 #aga -- seldom produc$ by e>?quakes :i* orig9ate inl&1 #age -- on velocity ( propagation (1 #agg -- examples (1 #agi ,seasons1 frequ5cy ( e>?quakes at diff]5t1 #bed ,seeba*1 on ! det]m9ation ( orig9s1 #baa -- on ! focal cavity1 #bbd ,seismic v]tical1 def9ition (1 #i ,seismic & volcanic ph5om5a1 relation (1 #bgj -- -- conclusions reg>d+1 #bge1 #bie ,seismology1 def9ition (1 #i ,seismomet]s1 on v>i\s =ms (1 #ag-dj ,seismoscopes1 on v>i\s =ms (1 #ac-bj ,s]pi]i1 ,p4 ,a41 on di/ribution ( seismic movem5t1 #bca ,%ad[s1 on e>?quake1 #acg ,spr+1 on frequ5cy ( e>?quakes dur+1 #aef ,/ukeley1 on e>?quake motion1 #db -- e>?quakes & aurora1 #bfe ,succussatore1 def9ition (1 #aj ,sun1 on ! effect (1 on e>?quakes1 #bec1 #bhe ,temp]ature1 effect ( *anges (1 on e>?quakes1 #bfh1 #bid ,t]remoto1 def9ition (1 #aj ,?omson1 ,sir ,w41 on ! rigidity ( ! e>?1 #bhe ,"t1 on record+ app>atus =1 #ce ,travag9i1 ,f41 on e>?quake motion1 #db ,trembelores1 def9ition (1 #aj ,tremors1 on e>?1 #c1 #cjf-cbe ,und]/&+1 effects ( e>?quakes on1 #b ,v]beck1 on ! ball & plate seismomet] (1 #ca ,vibration1 on ! nature ( e>?quake1 #ab ,vorticose motion1 on1 #gj -- def9ition (1 #aj ,wag5]1 on ! p5dulum seismomet] (1 #be -- v]tical motion seismomet] (1 #cc -- li/ ( e>?quakes1 #gf ,wave pa?s1 def9ition (1 #i ,waves1 on ! nature ( e>?quake1 #ee -- on ! int]f]5ce (1 #ach ,wells1 on ! effect ( e>?quakes on1 #aef ,w5?rop1 on ! ,new ,zeal& e>?quake ( #ahee1 #gi ,we/1 on ! p>allel motion seismomet] (1 #bh ,w9sl[1 on pulsations ( ! ocean1 #ccd ,wolf1 ,r41 on e>?quakes & sun spots1 #bfc ,woodw>d1 on e>?quake motion1 #db ,"y1 ,dr4 ,t41 on e>?quake motion1 #dc ,zant$es*i1 ,m4 ,f41 on ! influ5ce ( ! sun & moon on e>?quakes1 #bhe ,zlln]1 on ! bracket seismomet] (1 #bg -- on e>? tremors1 #cji ---------------------------------------- ---------------------------- ,,footnotes3 #a ,mmoires de l',acadmie ,imp4 de ,dijon1 vols4 xiv4 & xv41 #bnd ,s]ies1 #ahee-ef4 #b ,trans4 ,seis4 ,soc4 ( ,japan1 vol4 iii4 p4 #fe4 #c ,g5tleman's ,magaz9e1 #agec4 #d #a ,k+s xix4 #aa1 #ab4 #e #8,notes on ! ,great ,e>?quake ( ,japan4' ,j4 ,milne1 ,trans4 ,seis4 ,soc4 ( ,japan1 vol4 iii4 #f ,see ,mallet's ,li/ ( ,works on ,e>?quakes1 ,report ( ! ,briti% ,association1 #aheh1 p4 #ajg4 #g ,qu>t]ly ,review1 vol4 lxiii4 p4 #fa4 #h ,de ,mundo1 c4 iv4 #i ,see ,phil4 ,trans4 ,r4 ,s41 ,"p ,,iii4 #ahhb4 #aj ,report ( ! ,briti% ,association1 #ahea4 #aa #8,on ! ,velocity ( ,transmission ( ,e>? ,waves1' by ,g5]al ,h4 ,l1 ,abbot1 ,am]ican1 ,j\rnal ( ,sci5ce & ,arts1 vol4 xv4 ,m>* #ahgh2 #8,%ock ( ! ,explosion at ,hallet's ,po9t1' by ,bvt4 ,brig4-,g54 ,h5ry ,l4 ,abbot1 read be=e ! ,essayons ,club ( ! ,corps ( ,eng9e]s1 ,nov4 #ahgf4 #ab ,we/4 ,rev41 ,july #ahdi4 #ac ,phil4 ,trans41 ,l41 #agee4 #ad ,! solution is tak5 f ,mallet's ,acc\nt ( ! ,neapolitan ,e>?quake1 vol4 i4 p4 #aee4 #ae ,neapolitan ,e>?quake1 ii4 p4 #cjj4 #af ,see ,ed9burgh ,phil4 ,trans41 vol4 xxxi4 #ag ,see ,report ( ,briti% ,association1 #aheh1 p4 #aj4 #ah ,meteorologia ,endog5a1 i4 p4 #cjf4 #ai ,see rem>ks on ! ,e>?quake #8,pu%1' p4 #afb4 #bj ,see ,rese>*es 9 ,geology & ,natural ,hi/ory1 p4 #cgd4 #ba #8,! ,city ( ,e>?quakes1' ,h4 ,d4 ,w>n]1 ,atlantic ,mon?ly1 ,m>*1 #ahhc4 #bb ,mallet1 ,dynamics ( ,e>?quakes4 #bc ,/ud ,mill at ,hayw>ds4 #bd ,see #8,con/ructive ,art 9 ,japan1' by ,r4 ,h4 ,brunton1 ,c4,e41 ,f4,r4,g4,s41 ,f4,g4,s41 ,transactions ( ,asiatic ,society ( ,japan1 ,decemb] #bb1 #ahgc1 & ,janu>y #ac1 #ahge4 #be ,j\rnal ( ! ,am]ican ,geographical ,society1 vol4 x4 #bf ,phil4 ,trans41 li4 #agfj4 #bg ,ibid41 xviii4 #bh #8,! ,city ( ,e>?quakes1' ,h4 ,d4 ,w>n]1 ,atlantic ,mon?ly1 ,m>* #ahhc4 #bi ,t4 ,ronaldson1 ,a ,treatise on ,e>?quake ,dang]s c4 #cj ,pr9ciples ( ,geology1 ,lyell1 vol4 ii4 p4 #ajf4 #ca ,! ,neapolitan ,e>?quake ( #aheg1 ,r4 ,mallet1 vol4 ii4 p4 #cei4 #cb ,am4 ,j4 ,sci4 x4 #aia4 #cc ,reports ( ,briti% ,association1 #aheh1 p4 #ajf4 #cd ,see *apt] #8,causes ( ,e>?quakes' = details ( ?is my?4 #ce ,am4 ,j\r4 ,sci4 vol4 x4 p4 #aia4 #cf ,! ,e>?1 p4 #eii4 #cg ,lyell1 ,pr9ciples ( ,geology1 vol4 ii4 *ap4 xxix4 #ch ,g5t4 ,mag4 vol4 xx4 p4 #bab4 #ci ,trans4 ,seis4 ,soc4 vol4 v4 p4 #fg-fh4 #dj ,am4 ,j\r4 ,sci4 vol4 iv4 #da ,phil4 ,trans4 vol4 xviii4 #db ,oldham & ,mallet1 #8,ca*> ,e>?quake1' ,proc4 ,geolog4 ,soc4 #ahgb4 #dc ,phil4 ,trans4 vols4 li4 & xviii42 ,g5t4 ,mag4 vol4 xx4 #bab4 #dd ,trans4 ,royal ,geog4 ,soc4 vol4 vi4 #de ,phil4 ,trans4 vols4 xxxvi4 & xxxix4 #df ,am4 ,j\r4 ( ,sci4 #ahfe1 vol4 xl4 p4 #cfe4 #dg ,proc4 ,geolog4 ,soc4 ,ap4 #ahge1 p4 #bgj4 #dh ,g5t4 ,mag4 vol4 xxi4 p4 #efi4 #di ,jahrb4 f4 ,m94 #ahdj1 p4 #agc4 #ej ,oldham & ,mallet1 #8,ca*> ,e>?quake1' ,trans4 ,geolog4 ,soc4 ,ap4 #ahgb4 #ea ,o4 ,volg]1 ,unt]s b4 d4 ,phn4 d4 ,erdb4 vol4 iii4 p4 #dad4 #eb ,meteorologia ,endog5a1 vol4 i4 p4 #aff4 #ec ,g5t4 ,mag4 vol4 xxvi4 p4 #ia4 #ed ,compte ,r5du1 #ahgc1 p4 #ff4 #ee ,an ,hi/orical ,acc\nt ( ,e>?quakes1 p4 #df4 #ef ,phil4 ,trans4 vol4 xlix4 p4 #dcf4 #eg ,am4 ,j\r4 ,sci4 vol4 xlv4 p4 #abi4 #eh ,phil4 ,trans4 vol4 xlix4 p4 #edg4 #ei ,ibid4 vols4 xlii4 & xxxix4 #fj ,phil4 ,trans4 vol4 xlix1 "p i4 #fa ,compte ,r5du1 #ahgc1 "p ii4 p4 #ff4 #fb ,die ,vulcan4 ,ers4 d4 ,erde1 ,c4 ,w4 ,c4 ,fu*s4 #fc ,comte ,r5du1 #ahge1 p4 #fic4 #fd ,g5t4 ,mag4 vol4 xix4 p4 #aij4 #fe ,phil4 ,trans4 vol4 xlix4 p4 #aae4 #ff ,g5t4 ,mag4 vol4 xxi4 #agea4 #fg ,j\r4 ,royal ,geo4 ,soc4 vol4 vi4 p4 #cai4 #fh ,d>w91 ,geolog4 ,obs]vations1 p4 #bcb4 #fi ,ibid4 p4 #bde4 #gj ,lyell1 ,pr9ciples ( ,geology1 vol4 ii4 pp4 #ajg-h4 #ga ,g5t4 ,mag4 #agcc1 vol4 iii4 p4 #bag4 #gb #8,e>?quakes ( ,cut*1' ,j\r4 ,royal ,geo4 ,soc4 vol4 xl4 #gc ,m4 ,daussy1 #8,sur l'exi/5ce probable d'un volcan s\sm>9 situ ar environ #j #bj de lat4 ,s41 et #bb #j de long1 oue/1' ,comptes ,r5dus1 vol4 vi4 p4 #eab4 #gd ,am4 ,j\r4 ,sci4 vol4 xlv4 p4 #acc4 #ge ,am4 ,j\r4 ,sci4 vol4 xiv4 p4 #bji4 #gf ,d4 ,c4 ,f4 ,w9sl[1 #8,tides at ,tahiti1' ,am4 ,j\r4 ,sci4 #ahfe1 p4 #de2 also ,mallet's ,catalogue ( ,e>?quakes4 #gg ,am4 ,j\r4 ,sci4 vol4 i4 p4 #dfi4 #gh ,d>w91 ,rese>*es 9 ,geology1 c41 p4 #cgh4 #gi ,kluge1 ,jahrb4 f4 ,m94 #ahfa1 p4 #igg4 #hj ,d>w91 ,voyage ( a ,naturali/1 p4 #cji4 #ha ,pr(4 ,a4 ,d4 ,ba*e1 ,unit$ ,/ates ,coa/ ,survey ,report1 #ahee1 p4 #cdb4 #hb ,unit$ ,/ates ,coa/ ,surrey ,report1 or ,am4 ,j\r4 ,sci4 vi4 p4 #gg4 #hc ,pet]mann's ,mit!ilung51 #ahgg1 ,heft xii4 ,s4 #ded1 & ,nova ,acta d] ,ksl4 ,leop4 ,c>ol4 ,deuts*5 ,acad4 d ,natur=s*]1 ,b& xl4 ,no4 #i4 #hd ,j4 ,milne3 #8,p]uvian ,e>?quake ( ,may #i1 #ahgg4' ,see ,trans4 ,seis4 ,soc4 ( ,japan1 vol4 ii4 #he ,report ( ,briti% ,association1 #ahdg1 p4 #hd4 #hf ,das ,erdbeb5 von ,h]zog5ra?1 c41 p4 #acd4 #hg ,phil4 ,trans4 vol4 li4 #hh ,see ,am4 ,j\r4 ,sci4 #ahgb4 #hi ,david ,milne says t #8out ( #aaj %ocks record$ 9 ,engl&1 ?irty-"o orig9at$ 9 ,wales1 ?irty-"o along ! s\? coa/ ( ,engl&1 f\rte5 on ! bord]s ( ,york%ire & ,d]by%ire1 & five or six 9 ,cumb]l&4' #ij ,e4 ,suess1 ,die ,erdbeb5 ,ni$]/]rei*es4 #ia ,h4 ,hoeff]1 ,die ,erdbeb5 ,krnt5s4 #ib ,six ,lectures on ,physical ,geography1 by ,rev4 ,s4 ,haughton1 ,f4,r4,s41 *ap4 i4 #ic ,ramsay1 #8,geological ,hi/ory ( ,m\nta9 ,*a9s1' ,m9+ ,j\rnal4 #id ,a notable example ( a rapid dim9ution 9 ! numb] ( e>?quakes felt at a place is t ( ,comrie 9 ,scotl&4 ,9 #ahci-dj1 no less ?an sixty %ocks 7 felt 9 elev5 mon?s4 ,9 #ahdb-dc1 ab\t ?irty %ocks 7 felt1 & 9 ! foll[+ ye> ?irty-sev54 ,s9ce ?is "t ! numb] ( %ocks has decreas$ until !y are almo/ ( z r>e occurr5ce at ,comrie z 9 o!r portions ( ! ,briti% ,isles4 #ie ,phil4 ,trans4 vol4 i4 #ahcf4 #if ,am4 ,j\r4 ( ,sci4 vol4 xxxvii4 p4 #a4 #ig ,milne1 #8,briti% ,e>?quakes1' ,ed94 ,phil4 ,j\r4 vol4 xxxi4 #ih ,phil4 ,trans4 vol4 xlix4 pt4 i4 #ii ,compte ,r5dus1 #ahge1 p4 #fij4 #ajj ,am4 ,j\r4 ,sci4 vol4 xi4 p4 #bcc4 #aja ,transactions ( ! ,asiatic ,society ( ,japan1 vol4 vi4 pt4 i4 p4 #cec4 #ajb ,kluge1 ,ueb] die ,ursa*51 c41 p4 #gd4 #ajc ,am4 ,j\r4 ,sci4 vol4 xix4 p4 #afb4 #ajd ,mitt4 d4 ,deuts*4 ,ges41 ,aug4 #ahgh4 #aje ,report to ,briti% ,association1 #ahej1 p4 #gd4 #ajf ,fu*s1 ,die ,vulkanis*5 ,ers*e9ung5 d] ,erde1 p4 #dbd4 #ajg ,b]n4 ,naturf4 ,gesells*aft1 #aheb4 #ajh ,comptes ,r5dus1 #ahgd1 ,jan4 to ,june1 p4 #ea4 #aji ,b\1 ,p>allele d] ,erdbeb51 ,nordli*t] und ,erdmagnetismus1 9 ,sitz4 d] ,k4 ,a4 d4 ,wiss5s*4 #ahef1 vol4 iv4 p4 #cie4 #aaj ,meteorologia ,endog5a1 vol4 i4 p4 #ajg1 c4 #aaa ,phil4 ,trans4 vol4 lxviii4 p4 #bba4 #aab ,g5t4 ,mag4 vol4 xxvii4 p4 #ejh4 #aac ,die ,vulkanis*5 ,ers*e9ung5 d] ,erde1 p4 #dai4 #aad ,pet]mann's ,geogr4 ,mit?4 #aheh1 sec4 #bdf4 #aae ,notes on volcanoes ( ! ,hawaiian ,isl&s1 ,w4 ,t4 ,brigham1 ,mem4 ,bo/on ,soc4 ( ,nat4 ,hi/41 #ahfh4 #aaf ,g5t4 ,mag4 vol4 xxiii41 #agec4 #aag ,j\r4 ,royal ,geog4 ,soc4 vol4 vi4 #aah ,ibid4 vol4 vi4 #aai ,phil4 ,trans4 vol4 xlii4 #abj ,am4 ,j\r4 ,sci4 vol4 x4 p4 #aia4 #aba #8,e>?quakes ( ,san ,salvador1 ,decemb] #ba-cj1 #ahgi4' ,am4 ,j\r4 ,sci4 vol4 xix4 p4 #dae4 #abb ,g5t4 ,mag4 #ageg1 p4 #cbc4 #abc ,phil4 ,trans4 vol4 li41 #agfj4 #abd ,mallet1 ,report to ,brit4 ,ass41 #aheh1 p4 #fg4 #abe ,von ,lasaulx1 ,e>?quakes ( ,h]zog5ra?4 #abf ,lyell1 ,pr9ciples1 vol4 ii4 p4 #ea4 #abg ,lyell1 ,pr9ciples1 vol4 i4 p4 #djb4 #abh ,fu*s1 p4 #dfd4 #abi ,comptes ,r5dus1 ,augu/ #ahed4 #acj ,nature1 ,april #bf1 #ahhc4 #aca ,phil4 ,soc41 ,well+ton1 ,new ,zeal&1 #ahge4 #acb ,phil4 ,trans41 vol4 xlii4 #acc ,m4 ,s4 di ,rossi1 ,e>?quakes ( ,casamicciola4 #acd ,phil4 ,trans41 vol4 xviii4 #afhc-e4 #ace ,ibid4 vol4 xlix4 #acf ,h4 ,d4 ,w>n]1 #8,! ,city ( ,e>?quakes1' ,atlantic ,mon?ly1 ,m>* #ahcc4 #acg ,palm]1 ,trans4 ,seis4 ,soc4 ( ,japan1 vol4 iii4 p4 #adh4 #ach ,palm]1 ,trans4 ,seis4 ,soc4 ( ,japan1 vol4 iii4 p4 #adh4 #aci ,paul1 ,trans4 ,seis4 ,soc4 ( ,japan1 vol4 ii4 p4 #da4 #adj ,g4 ,h4 & ,h4 ,d>w91 ,reports ( ,briti% ,association1 #ahha4 #ada ,reports ( ,briti% ,association1 #ahha4 #adb ,comptes ,r5dus1 #ahge1 ,janu>y to ,june1 p4 #fhe4 #adc ,tel4 ,j\r41 ,novemb] #ae1 #ahha4 #add ,m9utes & proce$+s ( ! 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,,natural ,,conditions ,,( ,,exi/5ce4 ,by ,,k>l ,,semp]4 ,) #b ,maps & #ajf ,woodcuts4 #b4jj4 #ca4 ,,sight3 ,an ,exposition ( ! ,pr9ciples ( ,monocul> & ,b9ocul> ,vision4 ,by ,,joseph ,,le ,,conte1 ,,ll4 ,d4 ,) #acb ,illu/rations4 #a4ej4 #cb4 ,,g5]al ,,physiology ,,( ,,muscles ,,& ,,n]ves4 ,by ,pr(essor ,j4 ,,ros5?al4 ,) #ge ,illu/rations4 #a4ej4 #cc4 ,,illusions3 ,a ,psy*ological ,/udy4 ,by ,,james ,,sully4 #a4ej4 #cd4 ,,! ,,sun4 ,by ,c4 ,a4 ,,"y1 ,pr(essor ( ,a/ronomy 9 ! ,college ( ,new ,j]sey4 ,) num]\s ,illu/rations4 #b4jj4 #ce4 ,,volcanoes3 ,:at !y ,are & :at !y ,tea*4 ,by ,,john ,w4 ,,judd1 ,f4 ,r4 ,s41 ,pr(essor ( ,geology 9 ! ,royal ,s*ool ( ,m9es4 ,) #if ,illu/rations4 #b4jj4 #cf4 ,,suicide3 ,an ,essay 9 ,comp>ative ,moral ,/ati/ics4 ,by ,,h5ry ,,morselli1 ,m4 ,d41 ,pr(essor ( ,psy*ological ,m$ic9e1 ,royal ,univ]sity1 ,tur94 #a4ge4 #cg4 ,,! ,,=mation ,,( ,,vegetable ,,m\ld1 ,,?r\gh ,,! ,,action ,,( ,,worms4 ,) ,obs]vations on _! ,habits4 ,by ,,*>les ,,d>w91 ,,ll4 ,d41 ,f4 ,r4 ,s4 ,) ,illu/rations4 #a4ej4 #ch4 ,,! ,,concepts ,,& ,,!ories ,,( ,,mod]n ,,physics4 ,by ,j4 ,b4 ,,/allo4 #a4ge4 #ci4 ,,! ,,bra9 ,,& ,,its ,,functions4 ,by ,j4 ,,luys4 #a4ej4 #dj4 ,,my? ,,& ,,sci5ce4 ,by ,,tito ,,vignoli4 #a4ej4 #da4 ,,diseases ,,( ,,memory3 ,an ,essay 9 ! ,positive ,psy*ology4 ,by ,,?4 ,,ribot1 au?or ( 8,h]$ity40 #a4ej4 #db4 ,,ants1 ,,bees1 ,,& ,,wasps4 ,a ,record ( ,obs]vations ( ! ,habits ( ! ,social ,hym5opt]a4 ,by ,sir ,,john ,,lubbock1 ,b>t41 ,f4 ,r4 ,s41 ,d4 ,c4 ,l41 ,,ll4 ,d41 etc4 #b4jj4 #dc4 ,,sci5ce ,,( ,,politics4 ,by ,,%eldon ,,amos4 #a4ge4 #dd4 ,,animal ,,intellig5ce4 ,by ,,george ,j4 ,,romanes4 #a4ge4 #de4 ,,man ,,be=e ,,metals4 ,by ,n4 ,,joly1 ,correspond5t ( ! ,in/itute4 ,) #adh ,illu/rations4 #a4ge4 #df4 ,,! ,,organs ,,( ,,spee* ,,& ,,_! ,,application ,,9 ,,! ,,=mation ,,( ,,articulate ,,s\nds4 ,by ,g4 ,h4 ,,von ,,mey]1 ,pr(essor 9 ,ord9>y ( ,anatomy at ! ,univ]sity ( ,zri*4 ,) #dg ,woodcuts4 #a4ge4 #dg4 ,,fallacies3 ,a ,view ( ,logic f ! ,practical ,side4 ,by ,,alfr$ ,,sidgwick1 ,b4 ,a41 ,oxon4 #a4ge4 #dh4 ,,orig9 ,,( ,,cultivat$ ,,plants4 ,by ,,alphonse ,,de ,,c&olle4 #b4jj4 #di4 ,,jelly-,,fi%1 ,,/>-,,fi%1 ,,& ,,sea-,,ur*9s4 ,be+ a ,rese>* on ,primitive ,n]v\s ,sy/ems4 ,by ,,george ,j4 ,,romanes4 #a4ge4 #ej4 ,,! ,,common ,,s5se ,,( ,,! ,,exact ,,sci5ces4 ,by ! late ,,william ,,k+don ,,clif=d4 #a4ej4 #ea4 ,,physical ,,expression3 ,its ,modes & ,pr9ciples4 ,by ,,francis ,,w>n]1 ,m4 ,d41 ,assi/ant ,physician1 & ,lectur] on ,botany to ! ,london ,hospital1 etc4 ,) #ea ,illu/rations4 #a4ge4 #eb4 ,,an?ropoid ,,apes4 ,by ,,rob]t ,,h>tmann1 ,pr(essor 9 ! ,univ]sity ( ,b]l94 ,) #fc ,illu/rations4 #a4ge4 #ec4 ,,! ,,mammalia ,,9 ,,_! ,,relation ,,to ,,primeval ,,times4 ,by ,,osc> ,,s*midt4 #a4ej4 #ed4 ,,comp>ative ,,lit]ature4 ,by ,,hut*eson ,,macaulay ,,posnett1 ,m4 ,a41 ,,ll4 ,d41 ,f4 ,l4 ,s41 ,b>ri/]-at-,law2 ,pr(essor ( ,classics & ,engli% ,lit]ature1 ,univ]sity ,college1 ,auckl&1 ,new ,zeal&1 au?or ( 8,! ,hi/orical ,me?od10 etc4 #a4ge4 #ee4 ,,e>?quakes ,,& ,,o!r ,,e>? ,,movem5ts4 ,by ,,john ,,milne1 ,pr(essor ( ,m9+ & ,geology 9 ! ,imp]ial ,college ( ,eng9e]+1 ,tokio1 ,japan4 ,) #ch ,figures4 ,new ,york3 ,d4 ,,appleton ,,co41 #a1 #c1 #e ,bond ,/reet4 ,,volcanoes3 ,,:at ,,!y ,,are ,,& ,,:at ,,!y ,,tea*4 ,by ,j4 ,w4 ,,judd1 ,pr(essor ( ,geology 9 ! ,royal ,s*ool ( ,m9es 7,london74 ,) ,n9ety-six ,illu/rations4 #abmo4 ,clo?1 #b4jj4 8,! volume be=e u is "o ( ! pleasante/ sci5ce manuals we h read = "s "t40--,a!num4 8,mr4 ,judd's summ>y is s full & s concise1 t x is almo/ impossible to give a fair idea 9 a %ort review40--,pall ,mall ,gazette4 8,pr(essor ,judd discusses ! nature ( volcanic action1 ! int]nal /ructure ( volcanic m\nta9s1 ! di/ribution ( volcanoes ^u ! surface ( ! globe1 _! activity 9 diff]5t p]iods ( ! e>?'s exi/5ce1 ! use ( volcanoes 9 ! economy ( nature1 ! v>i\s !ories t h be5 made to expla9 volcanic action4 ,he has abbreviat$ 9 ?is volume a va/ am\nt ( in=mation1 :i* has a fasc9at+ int]e/ = _m m9ds by reason ( its relation to ! pa/ hi/ory & future de/9y ( ?is little bubble ( e>? ^u :i* we sail ?r\gh ! inf9ite spaces ( e!r40--,new ,york ,home ,j\rnal4 8,! book gives an exhau/ive /atem5t ( ! ph5om5a ( volcanoes1 & ( ! facts 9 ! =mation ( m\nta9-*a9s1 & relates a mass ( int]e/+ obs]vations & facts1 ! results ( pati5t & ext5sive p]sonal inve/igation & /udy1 mo/ly 9 diff]5t places 9 ,s\!rn ,europe1 b n neglect+ ! _w's l>g] volcanoes 9 o!r regions40--,h>t=d ,times4 8,a fasc9at+ example ( pati5t obs]vation1 s\nd judgm5t1 & acute reason+4 ,"u ,pr(essor ,judd's skillful treatm5t ! volcano is =c$ n only to tell its own hi/ory1 b also to solve a numb] ( e>? problems seem+ly disconnect$ ) x2 & ! /ory is told 9 /rong1 n]v\s language1 & ) an e>ne/ness & subdu$ en?usiasm t are delightfully /imulat+40--,bo/on ,gazette4 8,pr(essor ,judd fir/ po9ts out ! errors 9 ! old def9ition ( a volcano4 ,! volcanic hole is v (t5 n on ! summit1 b on ! side1 sometimes at ! base ( ! m\nta9 or hill1 & x s5ds =? /eam r ?an smoke1 & ! suppos$ rag+ flames are no?+ m ?an ! gl[+ light ( a mass ( molt5 mat]ial reflect$ f ^? vapor-cl\ds4 ,s our old ignorance vani%es1 & 9 ?is admirable "w ! int]nal /ructure ( volcanic m\nta9s1 ! nature & products ( volcanic action1 & ! di/ribution ( ! mat]ials reject$ f volcanic v5ts1 ! succession ( op]ations tak+ place at volcanic c5t]s1 are all v ably & cle>ly discuss$40--,philadelphia ,times4 8,a succ9ct & excell5t treatise on a v int]e/+ subject40--,philadelphia ,nor? ,am]ican4 ,= sale by all booksell]s2 or s5t by mail1 po/ paid1 on receipt ( price4 ,new ,york3 ,d4 ,,appleton ,,co41 #a1 #c1 #e ,bond ,/reet4 ,,! ,,concepts ,,& ,,!ories ,,( ,,mod]n ,,physics4 ,by ,j4 ,b4 ,,/allo4 #abmo1 clo? #a4ge4 8,judge ,/allo's "w is an inquiry into ! validity ( ^? me*anical conceptions ( ! univ]se :i* are n[ held z fundam5tal 9 physical sci5ce4 ,he takes up ! lead+ mod]n doctr9es :i* are bas$ ^u ?is me*anical conception1 su* z ! atomic con/itution ( matt]1 ! k9etic !ory ( gases1 ! cons]vation ( en]gy1 ! nebul> hypo!sis1 & o!r views1 to f9d h[ mu* /&s ^u solid empirical gr\nd1 & h[ mu* re/s ^u metaphysical speculation4 ,s9ce ! appe>ance ( ,dr4 ,drap]'s #8,religion & ,sci5ce1' no book has be5 publi%$ 9 ! c\ntry calculat$ to make s deep an impression on ?\ghtful & educat$ read]s z ?is volume4444 ,! range & m9ut5ess ( ! au?or's le>n+1 ! acut5ess ( 8 reason+1 & ! s+ul> precision & cle>ness ( 8 /yle1 are qualities :i* v seldom h be5 jo9tly exhibit$ 9 a sci5tific treatise40--,new ,york ,sun4 8,judge ,j4 ,b4 ,/allo1 ( ,c9c9nati1 is a ,g]man by bir?1 & came to ?is c\ntry at ab\t ! age ( sev5te54 ,he 0 e>ly famili> ) sci5ce1 & he lectur$ = "s ye>s 9 an ,ea/]n college2 b at l5g? he adopt$ ! pr(ession ( law4 ,he is also rememb]$ by _m z an au?or1 hav+ a numb] ( ye>s ago writt5 a metaphysical treatise ( m>k$ ability = "o ( 8 y\?ful ye>s4 ,8 pres5t book mu/ be read delib]ately1 mu/ be /udi$ to be appreciat$2 b ! /ud5ts ( sci5ce1 z well z ^? ( metaphysics1 are c]ta9 to be deeply int]e/$ 9 its logical developm5ts4 ,x is a timely & tell+ contribution to ! philosophy ( sci5ce1 imp]atively call$ = by ! pres5t exig5cies 9 ! progress ( k4 ,x is to be comm5d$ equally = ! solid value ( its cont5ts & ! s*ol>ly f9i% ( its execution40--,! ,popul> ,sci5ce ,mon?ly4 8,! book is ( vital int]e/ to a mu* l>g] class ?an speciali/s--to all1 9 fact1 :o value cle> ?9k+ or are int]e/$ 9 ! accuracy m ?an ! progress ( sci5tific ?\ght4 ,x deals ) ! results & !ories ( physical sci5ce1 & 9 no s5se ) ! processes ( ! laboratory4 ,x is writt5 ) a cle>ness t is uncommon 9 philosophic works & ) a desire to f9d tru?1 consci\s ( ! fact t a prime pr]equisite ( f9d+ x is to cle> ! way ( accumulat$ & fa/-settl+ untru?s4 ,x is a sci5tific rebuke1 z sev]e z x is lucid1 ( ! sci5ti/s :o leave _! app>atus & g />-gaz+3 "h is ! pit into :i* !y h fall540--,new ,york ,_w4 8,! volume is an important contribution to sci5tific discussion1 & is m>k$ by clos5ess ( reason+1 & cle>ness & cog5cy ( /atem5t40--,bo/on ,j\rnal4 ,= sale by all booksell]s2 or s5t by mail1 po/ paid1 on receipt ( price4 ,new ,york3 ,d4 ,,appleton ,,co41 #a1 #c1 #e ,bond ,/4 ,transcrib]'s ,notes3 - ,text enclos$ by und]scores is 9 italics 7italics74 - ,text enclos$ by equals is 9 bold 7bold74 - ,blank pages h be5 remov$4 - ,sil5tly correct$ typographical errors4 - ,spell+ & hyph5ation v>iations made consi/5t4 - ,front publication li/ mov$ to ! back4 - ,tables pages #gg1 #hi3 remov$ unne$$ "r braces4 - ,tables pages #bdj1 #beg3 *ang$ to use cell bord]s in/ead ( "r braces4 - ,table page #bei3 ,nor!rn ,hemisph]e av]age #aej correct$ to #aej4