99 99 99 99 99 ---------------------------------------- ------------------- ,transcrib]'s ,note3 ,inconsi/5t hyph5ation 9 ! orig9al docum5t has be5 pres]v$4 ,9 ! equations1 sup]script$ *>act]s are m>k$ ) 's1 & subscript$ *>act]s are m>k$ ) 7und]score7 9 front4 ,obvi\s typographical errors h be5 correct$4 ,= a complete li/1 please see ! end ( ?is docum5t4 ---------------------------------------- ------------------- 99 99 99 99 99 ,a ,,/udy ,,( ,,rec5t ,,e>?quakes4 ,,by ,,*>les ,,davison1 ,sc4,d41 ,f4,g4,s4 ,,au?or ,,( ,,! ,,h]e=d ,,e>?quake ,,( ,,decemb] #ag,,?1 #ahif4 ,,) #hj ,,illu/rations ,london & ,newca/le-on-,tyne3 ,,! ,,walt] ,,scott ,,publi%+ ,,co41 ,,ltd4 #aije ,,preface4 ,! pres5t volume diff]s f a text-book ( seismology 9 giv+ brief1 ?\gh detail$1 acc\nts ( individual e>?quakes r ?an a discussion ( ! ph5om5a & di/ribution ( e>?quakes 9 g5]al4 ,at ! close ( 8 ,les ,tremblem5ts de ,t]re1 ,pr(essor ,f\qu has devot$ a few *apt]s to "s ( ! pr9cipal e>?quakes betwe5 #ahed & #ahhg2 & !re are also ! well-kn[n *apt]s 9 ,lyell's ,pr9ciples ( ,geology deal+ ) e>?quakes ( a /ill e>li] date4 ,) ^! exceptions1 !re is no o!r "w cov]+ ! same gr\nd2 & he :o wi%es to /udy any p>ticul> e>?quake c only d s by read+ long reports or s]ies ( pap]s writt5 p]haps 9 sev]al diff]5t languages4 ,! object ( ?is volume is to save him ?is tr\ble1 & to pres5t to him ! facts t seem mo/ wor?y ( 8 att5tion4 ,! *apt] on ! ,japanese e>?quake is repr9t$1 ) a few slight additions1 f a pap] publi%$ 9 ! ,geographical ,j\rnal1 & ,i am indebt$ to ! editor1 n only = ! necess>y p]mission1 b also = 8 c\rtesy 9 furni%+ me ) cli*s ( ! blocks :i* illu/rat$ ! orig9al pap]4 ,! editor ( ,k has also all[$ me to use a pap] :i* appe>$ f\r ye>s ago z ! f\ndation ( ! n9? *apt] 9 ?is book4 ,,*>les ,,davison4 ,,birm+ham1 ,janu>y1 #aije4 ,,cont5ts4 ,,*apt] ,i4 ,,page ,,introduction #a ,,*apt] ,,ii4 ,,! ,,neapolitan ,,e>?quake ,,( ,,decemb] #af,,?1 #aheg #g ,,*apt] ,,iii4 ,,! ,,is*ian ,,e>?quakes ,,( ,,m>* #d,,?1 #ahha1 ,,& ,,july #bh,,?1 #ahhc #de ,,*apt] ,,iv4 ,,! ,,&alusian ,,e>?quake ,,( ,,decemb] #be,,?1 #ahhd #ge ,,*apt] ,v4 ,,! ,,*>le/on ,,e>?quake ,,( ,,augu/ #ca,,/1 #ahhf #ajb ,,*apt] ,,vi4 ,,! ,,rivi]a ,,e>?quake ,,( ,,febru>y #bc,,rd1 #ahhg #ach ,,*apt] ,,vii4 ,,! ,,japanese ,,e>?quake ,,( ,,octob] #bh,,?1 #ahia #agg ,,*apt] ,,viii4 ,,! ,,h]e=d ,,e>?quake ,,( ,,decemb] #ag,,?1 #ahif1 ,,& ,,! ,,inv]ness ,,e>?quake ,,( ,,septemb] #ah,,?1 #aija #bae ,,*apt] ,,ix4 ,,! ,,indian ,,e>?quake ,,( ,,june #ab,,?1 #ahig #bfb ,,*apt] ,x4 ,,conclusion #cba ,,index #cdi ,,li/ ,,( ,,illu/rations4 ,,fig4 ,,page #a4 ,diagram to illu/rate ,simple ,h>monic ,motion #d #b4 ,isoseismal ,l9es ( ! ,neapolitan ,e>?quake #i #c4 ,diagram to illu/rate ,wave-pa? & ,angle ( ,em]g5ce #ab #d4 ,diagram to illu/rate ,mallet's ,me?od ( det]m9+ ,position ( ,epic5tre #ad #e4 ,plan ( ,ca!dral ,*ur* at ,pot5za #af #f4 ,fall5 ,gate-pill>s ne> ,sapon>a #ag #g4 ,model to illu/rate ! ,motion ( an ,e>?-p>ticle dur+ an ,e>?quake #ai #h4 ,plan ( ,directions ( ,fall ( ,ov]turn$ ,/one-lamps at ,tokio dur+ ! ,e>?quake ( #ahid #ai #i4 ,meizoseismal ,area ( ,neapolitan ,e>?quake #bb #aj4 ,di/ribution ( ,dea?-rate )9 ,meizoseismal ,area ( ,neapolitan ,e>?quake #bd #aa4 ,diagram to illu/rate ,mallet's ,me?od ( det]m9+ ,dep? ( ,seismic ,focus #bf #ab4 ,v]tical ,section ( ,ca!dral ,*ur* at ,pot5za #bg #ac4 ,diagram ( ,wave-pa?s at ,seismic ,v]tical ( ,neapolitan ,e>?quake #bi #ad4 ,geological ,sket*-map ( ,is*ia #dg #ae4 ,isoseismal ,l9es ( ,is*ian ,e>?quake ( #ahha #ea #af4 ,isoseismal ,l9es ( ,is*ian ,e>?quake ( #ahhc #ei #ag4 ,diagram ( ,wave-pa?s at ,seismic ,v]tical ( ,is*ian ,e>?quake ( #ahhc #fb #ah4 ,diagram %[+ connection betwe5 ,dep? ( ,focus & ,rate ( ,decl9e 9 ,int5sity #fh #ai4 ,isoseismal ,l9es ( ,&alusian ,e>?quake accord+ to ,t>amelli & ,m]calli #gi #bj4 ,isoseismal ,l9es ( ,&alusian ,e>?quake accord+ to ,f\qu1 etc4 #ha #ba4 ,magnetograph ,records ( ,&alusian ,e>?quake at ,lisbon #hc #bb4 ,nature ( ,%ock ( ,&alusian ,e>?quake #hh #bc4 ,diagram to illu/rate ,v>iation 9 ,nature ( ,%ock #hi #bd4 ,/ructure ( ,meizoseismal ,area ( ,&alusian ,e>?quake #ajj #be4 ,isoseismal ,l9es ( ,*>le/on ,e>?quake #ajf #bf4 ,curve ( ,int5sity at ,*>le/on #aaj #bg4 ,flexure ( ,rails at ,j$burgh #aac #bh4 ,epic5tral ,isoseismal ,l9es ( ,*>le/on ,e>?quake accord+ to ,sloan #aah #bi4 ,epic5tral ,isoseismal ,l9es ( ,*>le/on ,e>?quake accord+ to ,dutton #aai #cj4 ,planes ( ,oscillation ( ,/opp$ ,p5dulum ,clocks at ,*>le/on #aba #ca4 ,diagram to illu/rate ,dutton's ,me?od ( det]m9+ ,dep? ( ,seismic ,focus #abd #cb4 ,diagram to expla9 ,orig9 ( ,regions ( ,defective ,int5sity #acf #cc4 ,isoseismal ,l9es ( ,rivi]a ,e>?quake #add #cd4 ,meizoseismal ,area ( ,rivi]a ,e>?quake #adh #ce4 ,nature ( ,%ock ( ,rivi]a ,e>?quake #aeb #cf4 ,seismographic ,record at ,moncali]i #aee #cg4 ,di/ribution ( ,obs]vatories at :i* ,magnetographs 7 di/urb$ by ,rivi]a ,e>?quake #aeh #ch4 ,record ( ,tide-gauge at ,nice #afc #ci4 ,record ( ,tide-gauge at ,g5oa #afd #dj4 ,di/ribution ( ,seismic ,activity 9 ! ,rivi]a #agb #da4 ,isoseismal ,l9es ( ,japanese ,e>?quake #agh #db4 ,/ructure ( ,meizoseismal ,area ( ,japanese ,e>?quake #ahj #dc4 ,plan ( ,directions ( ,fall ( ,ov]turn$ ,bodies at ,nagoya #ahg #dd4 ,map ( ,mean ,directions ( ,%ock & ,isoseismal ,l9es 9 ,c5tral ,di/rict ( ,japanese ,e>?quake #ahh #de4 ,meizoseismal ,area ( ,japanese ,e>?quake #aij #df4 ,fault-sc>p ne> ,fujitani #aia #dg4 ,fault-sc>p at ,midori #aib #dh4 ,displacem5t ( ,field-divisions by ! ,fault ne> ,ni%i-,katabira #aic #di4 ,map ( ,swamp =m$ by ,/oppage ( ,riv] ,toba by ,fault-sc>p #aid #ej4 ,%ift+ ( ,trees by ,fault at ,umh>a #aie #ea4 ,daily ,frequ5cy ( ,aft]-%ocks at ,gifu & ,nagoya #aif #eb4 ,mon?ly ,frequ5cy ( ,aft]-%ocks at ,gifu #aig #ec4 ,di/ribution ( ,prelim9>y ,%ocks 9 ,space #bjb #ed4 ,di/ribution ( ,aft]-%ocks 9 ,space1 ,nov4-,dec4 #ahia #bjc #ee4 ,di/ribution ( ,aft]-%ocks 9 ,space1 ,jan4-,feb4 #ahib #bjd #ef4 ,di/ribution ( ,aft]-%ocks 9 ,space1 ,m>*-,april #ahib #bje #eg4 ,di/ribution ( ,aft]-%ocks 9 ,space1 ,may-,june #ahib #bjf #eh4 ,di/ribution ( ,audible ,aft]-%ocks 9 ,space1 ,nov4 #ahia-;,dec4 #ahib #bjh #ei4 ,map ( ,adjo9+ ,regions 9 :i* ,seismic ,activity 0 affect$ by ,japanese ,e>?quake #baj #fj4 ,isoseismal & ,isac\/ic ,l9es ( ,h]e=d ,e>?quake #baf #fa4 ,nature ( ,%ock ( ,h]e=d ,e>?quake #bbb #fb4 ,coseismal ,l9es ( ,h]e=d ,e>?quake #bbh #fc4 ,map ( ,m9or ,%ocks ( ,h]e=d ,e>?quake #bci #fd4 ,geology ( ,meizoseismal ,area ( ,h]e=d ,e>?quake #bda #fe4 ,isoseismal ,l9es ( ,inv]ness ,e>?quake #bdh #ff4 ,diagram to illu/rate suppos$ ,fault-displacem5t caus+ ,inv]ness ,e>?quake #bef #fg4 ,map ( ,epic5tres ( ,aft]-%ocks ( ,inv]ness ,e>?quake #beh #fh4 ,isoseismal ,l9es ( ,indian ,e>?quake #bfc #fi4 ,section ( ,tombs 9 ,cemet]y at ,*]rapunji #bgj #gj4 ,"t-curve ( ,indian ,e>?quake #bgh #ga4 ,seismographic ,record ( ,indian ,e>?quake at ,rocca di ,papa #bhb #gb4 ,seismographic ,record ( ,indian ,e>?quake at ,ed9burgh #bhc #gc4 ,displacem5t ( ,alluvium at ,foot ( a ,hill #bhg #gd4 ,twi/+ ( ,monum5t at ,*hatak #bid #ge4 ,epic5tral ,area ( ,indian ,e>?quake #cjc #gf4 ,plan ( ,*$rang ,fault #cje #gg4 ,re-triangulation ( ,khasi ,hills #cac #gh4 ,diagram ( ,?ru/-planes #cah #gi4 ,seismographic ,record ( ,tokio ,e>?quake ( #ahid #cbi #hj4 ,"t-curves ( ,pr9cipal ,epo*s ( ,e>?quake-waves ( ,di/ant ,orig9 #cch ,a ,,/udy ,,( ,,rec5t ,,e>?quakes4 ,,*apt] ,i4 ,,introduction4 ,i propose 9 ?is book to describe a few ( ! m important e>?quakes t h occurr$ dur+ ! la/ half c5tury4 ,9 judg+ ( importance1 ! /&>d :i* ,i h adopt$ is n t ( int5sity only1 b r ( ! sci5tific value ( ! results t h be5 a*iev$ by ! /udy ( ! %ocks4 ,ev5 ) ?is res]vation1 ! numb] ( e>?quakes t might be includ$ is consid]able2 & ,i h !re=e select$ ^? :i* seem to illu/rate be/ ! diff]5t me?ods ( inve/igation employ$ by seismologi/s1 or :i* are ( special int]e/ ow+ to ! unusual "* ( _! ph5om5a or to ! light ca/ by !m on ! nature & orig9 ( e>?quakes 9 g5]al4 ,?us1 ! ,neapolitan e>?quake possesses int]e/ f a hi/orical po9t ( view2 x is ! fir/ e>?quake 9 ! /udy ( :i* mod]n sci5tific me?ods 7 employ$4 ,! ,is*ian e>?quakes are describ$ z examples ( ^? connect$ ) volcanic action2 ! ,&alusian e>?quake is *iefly rem>kable = ! recognition ( ! unfelt e>?-waves2 t ( ,*>le/on = ! detection ( ! d\ble epic5tre & ! calculation ( ! velocity ) :i* ! vibrations travell$4 ,9 ! ,rivi]a e>?quake are comb9$ ! pr9cipal features ( ! la/ two %ocks ) sev]al ph5om5a ( miscellane\s int]e/1 especially ^? connect$ ) its subm>9e foci4 ,! ,japanese e>?quake is di/+ui%$ f o!rs by its extraord9>y fault-sc>p & ! v num]\s %ocks t foll[$ x4 ,! ,h]e=d e>?quake is a typical example ( a tw9 e>?quake1 & provid$ _m obs]vations on ! s\nd ph5om5a2 :ile ! ,inv]ness e>?quakes are important on acc\nt ( _! connection ) ! gr[? ( a well-kn[n fault4 ,! great ,indian e>?quake owns few1 if any1 rivals )9 hi/orical times1 :e!r we consid] ! int5sity ( ! di/urbance or ! div]sity & int]e/ ( ! ph5om5a display$ by x--! widespread *anges 9 ! e>?'s cru/1 bo? sup]ficial & deep-seat$1 & ! track+ ( ! unfelt pulsations completely r\nd ! globe4 ,,t]ms ,,& ,,def9itions4 ,"s t]ms are ( su* frequ5t use 9 describ+ e>?quakes t x w be conv5i5t to gr\p !m "h = ref]5ce1 o!rs m r>ely employ$ be+ introduc$ z !y are requir$4 ,an e>?quake is caus$ by a sudd5 displacem5t ( ! mat]ial :i* composes ! e>?'s int]ior4 ,! displacem5t gives rise to s]ies ( waves1 :i* are propagat$ outw>ds 9 all directions1 & :i*1 :5 !y rea* ! surface1 produce ! s5sations kn[n to u z ^? ( an e>?quake4 ,! region )9 :i* ! displacem5t occurs is sometimes call$ ! hypoc5tre1 b m frequ5tly ! seismic focus or simply ! focus4 ,! portion ( ! e>?'s surface :i* is v]tically above ! seismic focus is call$ ! epic5tre4 ,! focus & epic5tre are (t5 spok5 ( = conv5i5ce z if !y 7 po9ts1 & !y may !n be reg>d$ z ! c5tres ( ! region & area 9 :i* ! int5sity 0 greate/4 ,?is is n q accurate1 b to attempt a m exact def9ition w\ld at pres5t be out ( place4 ,an isoseismal l9e is a curve :i* passes ?r\gh all po9ts at :i* ! int5sity ( ! %ock 0 ! same4 ,x is b r>ely t ! absolute int5sity at any po9t ( an isoseismal l9e c be asc]ta9$1 & only "o example is giv5 9 ?is volume4 ,z a rule1 ! int5sity ( a %ock is det]m9$ by ref]5ce to ! degrees ( diff]5t arbitr>y scales4 ,^! w be quot$ :5 requir$4 ,9 e /rong e>?quake !re is a c5tral di/rict :i* diff]s 9 a m>k$ mann] f t outside 9 ! f> great] /r5g? & complexity ( ! ph5om5a4 ,z ?is di/rict includes ! epic5tre1 x is sometimes ref]r$ to z ! epic5tral area1 b ! t]m meizoseismal area is m appropriate1 & w be employ$ accord+ly4 ,! di/rict ov] :i* an e>?quake is p]ceptible to human be+s )\t in/rum5tal aid is its di/urb$ area4 ,9 l mann]1 t ov] :i* ! e>?quake-s\nd is he>d is ! s\nd-area4 ,a great e>?quake nev] occurs alone4 ,x is m]ely ! mo/ prom95t memb] ( a gr\p ( %ocks ( great] or less int5sity1 & is kn[n z ! pr9cipal %ock or e>?quake1 :ile ! o!rs are call$ m9or or accessory %ocks1 & =e-%ocks or aft]-%ocks accord+ z !y occur be=e or aft] ! pr9cipal e>?quake4 ,:5 ! s\nd only is he>d1 )\t an accompany+ tremor be+ any:]e p]ceptible1 x is m accurately call$ an e>?-s\nd1 b is frequ5tly = conv5i5ce numb]$ among ! m9or %ocks4 ,illu/ration3 ,,fig4 #a4--;,diagram to illu/rate simple h>monic motion4 ,! movem5t ( ! gr\nd dur+ a vibration ( ! simple/ "* 7kn[n z simple h>monic motion7 is repres5t$ 9 ,fig4 #a4 ,! po9t] ( ! record+ seismograph is "h suppos$ to oscillate along a l9e at "r angles to ,,ab1 & ! smok$ pap] or glass on :i* ! record is made to travel to ! left4 ,! di/ance ,,mp ( ! cre/ ,p ( any wave f ! l9e ,,ab repres5ts ! amplitude ( ! vibration1 ! sum ( ! di/ances ,,mp & ,,nq its range1 & ! l5g? ,,ab ! p]iod ( ! vibration4 ,f ! amplitude & p]iod we c calculate1 9 ! case ( simple h>monic motion1 bo? ! maximum velocity & maximum accel]ation ( ! vibrat+ p>ticles ( ! gr\nd4#a ,a few t]ms describ+ ! nature ( ! %ock are also 9 common use among ,italians & ,spani>ds4 ,an undulatory %ock consi/s ( "o or sev]al waves1 ! movem5t to & fro be+ along a ne>ly horizontal l9e2 a subsultory %ock ( movem5ts 9 a ne>ly v]tical direction2 :ile a vorticose %ock consi/s ( undulatory or subsultory movem5ts cross+ "o ano!r 9 diff]5t directions4 ,,orig9 ,,( ,,e>?quakes4 ,e>?quakes are gr\p$1 accord+ to _! orig91 into ?ree classes4 ,! fir/ consi/s ( slight local %ocks1 caus$ by ! fall ( rock 9 und]gr\nd passages2 ! second ( volcanic e>?quakes1 also local 9 "*1 b (t5 ( consid]able int5sity ne> ! c5tre ( ! di/urb$ area2 :ile 9 ! ?ird class we h tectonic e>?quakes1 or ^? directly connect$ ) ! %ap+ ( ! e>?'s cru/1 :i* v>y 9 /r5g? f ! weake/ p]ceptible tremor to ! mo/ de/ructive & widely felt %ock4 ,( ! e>?quakes describ$ 9 ?is volume1 ! ,is*ian e>?quakes belong to ! second class1 & all ! o!rs to ! ?ird4 ,t tectonic e>?quakes are closely connect$ ) ! =mation ( faults seems n[ e/abli%$ beyond d\bt4 ,!y occur f> f all traces ( rec5t volcanic action4 ,_! isoseismal l9es are elongat$ 9 directions p>allel to kn[n faults1 & ?is is sometimes ! case 9 "o & ! same di/rict ) faults t occur at "r angles to "o ano!r4 ,inde$1 :5 sev]al isoseismals are c>efully drawn1 x is possible f _! =m & relative position to pr$ict ! position ( ! orig9at+ fault4#b ,! initial =mation & fur!r spread+ ( ! r5t may be ! cause ( a few e>?quakes1 b by f> ! l>g] numb] are due to ! subsequ5t gr[? ( ! fault4 ,! relative displacem5t ( ! rocks adjo9+ ! fault1 :i* may am\nt to ?\s&s ( feet1 occasionally ev5 to miles1 is ! result1 n ( "o great movem5t1 b ( innum]able slips tak+ place 9 diff]5t p>ts ( ! fault & spread ov] va/ ages ( "t4 ,) e fault-slip1 int5se friction is sudd5ly br\ght into action by ! rubb+ ( "o mass ( rock aga9/ ! o!r2 &1 accord+ to ! mod]n view1 x is ?is friction t gives rise to ! e>?quake waves4 ,9 mo/ e>?quakes1 ! slip takes place at a consid]able dep?1 p]haps n less ?an "o or sev]al miles1 & ! v]tical slip is s small t x dies out be=e rea*+ ! surface4 ,b1 9 a few viol5t e>?quakes1 su* z ! ,japanese & ,indian e>?quakes describ$ 9 ?is volume1 ! slip is cont9u$ up to ! surface & is left visible !re z a small cliff or fault-sc>p4 ,9 ^! cases1 ! sudd5 spr+ ( ! cru/ may increase & complicate ! effects ( ! vibratory %ock4 ,,footnotes3 #a ,if a is ! amplitude ( ! vibration & ,t its p]iod1 ! maximum velocity is #b99pi99a_/,t & ! maximum accel]ation #d99pi#b;a_/,t#b #b ,see ,*apt] ,,viii41 on ! ,h]e=d & ,inv]ness e>?quakes4 ,,*apt] ,,ii4 ,,! ,,neapolitan ,,e>?quake ,,( ,,decemb] #af,,?1 #aheg4 ,half a c5tury ago1 seismology 0 9 its infancy4 ,on ! ,cont95t1 ,alexis ,p]rey ( ,dijon 0 compil+ 8 e>?quake catalogues ) unfail+ en?usiasm & indu/ry4 ,9 #ahdf1 ,rob]t ,mallet appli$ ! laws ( wave-motion 9 solids1 z !y 7 !n kn[n1 to ! ph5om5a ( e>?quakes2 & 8 memoir on ! ,dynamics ( ,e>?quakes#c may be reg>d$ z ! f\ndation-/one ( ! new sci5ce4 ,dur+ ! next twelve ye>s he contribut$ 8 well-kn[n ,reports to ! ,briti% ,association1#d & prep>$ a s]ies ( in/ructions = ! obs]vation & /udy ( e>?quake-%ocks4#e ,! latt]1 x is wor? not+1 conta9s an outl9e1 b h>dly m ?an an outl9e1 ( ! me?ods ( inve/igation :i* he develop$ & employ$ eight ye>s aft]w>ds 9 /udy+ ! ,neapolitan e>?quake4 ,! hi/ory ( ,mallet's prep>ation = 8 great "w is some:at /range4 ,no "o else at t "t possess$ s full a k ( e>?quake ph5om5a4 ,x 01 h[ev]1 a k t _h little1 if any1 f\ndation 9 actual exp]i5ce2 =1 :5 he 0 awak5$ by ! ,briti% e>?quake ( ,novemb] #i?1 #aheb1 he fail$ to recognise its seismic "*4 ,al?\gh ?is %ock di/urb$ an area ( ab\t #ge1jjj squ>e miles & 0 felt 9 all f\r p>ts ( ! k+dom1 ! paucity ( obs]vations & ! abs5ce ( durable records comb9$ 9 prev5t+ ! successful application ( 8 new modes ( /udy4#f ,nev]!less1 ) confid5ce un%ak5 9 _! p[]1 he await$ ! occurr5ce ( a m viol5t %ock1 b five ye>s _h to pass be=e 8 opportunity came t[>ds ! close ( #aheg4 ,s de/ructive 0 ! ,neapolitan e>?quake ( ?is ye> 7,mallet ranks x ?ird among ,european e>?quakes 9 ext5t & sev]ity71 t ne>ly a week elaps$ be=e any news ( x rea*$ ! out] _w4 ,)\t fur!r loss ( "t1 he appli$ = & obta9$ a grant ( money f ! ,c\ncil ( ! ,royal ,society1 & proce$$ e>ly 9 ! foll[+ ,febru>y to :at 0 !n ! k+dom ( ,naples4 ,arm$ ) lett]s ( au?ority to diff]5t (ficials1 he visit$ ! *ief t[ns & villages 9 ! meizoseismal area2 &1 9 spite ( unfav\rable wea!r & ! difficulties ( travell+ 9 a c\ntry s rec5tly deva/at$1 he complet$ 8 exam9ation 9 little m ?an two mon?s4 ,x 0 a task1 surely1 t w\ld h baffl$ any b ! mo/ en?usia/ic inve/igator or "o unspurr$ by ! feel+ t he possess$ ! key to "o ( ! mo/ obscure ( ,nature's problems4 ,mallet's confid5ce 9 ! accuracy ( 8 me?ods 0 almo/ unb\nd$4 ,8 great report 0 publi%$ f\r ye>s lat]2 b he seems to h reg>d$ x almo/ z a text-book ( obs]vational seismology & ! results ( 8 ,neapolitan "w z m]e illu/rations4 ,8 successors1 h[ev]1 h transpos$ ! ord] ( importance1 & rank 8 two l>ge volumes z ! model1 if n ! inspir]1 ( _m ( our m rec5t e>?quake monographs4 ,illu/ration3 ,,fig4 #b4--;,isoseismal ,l9es ( ! ,neapolitan ,e>?quake ( #aheg4 7,mallet47 ,,isoseismal ,,l9es ,,& ,,di/urb$ ,,area4 ,! position ( ! meizoseismal area1 to :i* ,mallet devot$ mo/ ( 8 "t1 is indicat$ by ! small oval area m>k$ #a 9 ,fig4 #b1 repres5t$ on a l>g] scale 9 ,fig4 #i4 ,x is #dj miles long & #bc miles wide1#g & conta9s #iej squ>e miles4 ,)9 ?is area1 ! loss ( life 0 great & mo/ ( ! t[ns 7 absolutely pro/rat$4 ,! next isoseismal1 ,no4 #b1 :i* is also %[n m cle>ly 9 ,fig4 #i1 b\nds ! area 9 :i* ! loss ( life 0 /ill great & _m p]sons 7 w\nd$1 :ile l>ge portions ( ! t[ns )9 x 7 ?r[n d[n4 ,its l5g? is #fe miles1 wid? #dg miles1 & area #b1bdj squ>e miles4 ,! ?ird isoseismal includes a di/rict 9 :i* build+s 7 only occasionally ?r[n d[n1 ?\gh none escap$ "s slight damage1 & 9 :i* practically no loss ( life occurr$4 ,?is curve is #ajc miles long1 #hb miles wide1 & includes #f1fae squ>e miles4 ,la/ly1 ! f\r? isoseismal m>ks ! b\nd>y ( ! di/urb$ area1 :i* is #bej miles long1 #baj miles wide1 & conta9s n m ?an #ci1bjj squ>e miles2 an am\nt t mu/ be reg>d$ z /rangely small1 & h>dly ju/ify+ ,mallet's e/imate ( ! ,neapolitan e>?quake z ! ?ird among ,european e>?quakes 9 ext5t z well z 9 sev5ty4 ,,damage ,,caus$ ,,by ,,! ,,e>?quake4 ,z reg>ds de/ruction to life & prop]ty1 h[ev]1 ! ,neapolitan e>?quake owns b few ,european rivals4 ,less fav\rable conditions = )/&+ a great %ock are seldom1 inde$1 to be f\nd ?an ^? possess$ by ! m$ival t[ns & villages ( ! meizoseismal area4 ,9 build+s ( e class1 ! walls are v ?ick & consi/ z a rule ( a co>se1 %ort-b$d$1 ill-laid rubble masonry1 )\t ?or\gh bond+ & connect$ by mort> ( sl5d] cohesion4 ,! floors are made ( planks coat$ ) a lay] ( concrete f six to eight in*es ?ick1 ! :ole weigh+ f sixty to a hundr$ p\nds p] squ>e foot4 ,only a little less heavy are ! ro(s1 :i* are cov]$ ) ?ick tiles secur$1 except at ! ridges1 by _! own weight alone4 ,?us1 = ! mo/ "p1 ! walls1 floors1 & ro(s are extremely massive1 :ile ! connections ( all to !mselves & to ea* o!r are loose & imp]fect4 ,aga91 ! t[ns1 = great] security f attacks 9 e>ly times1 are g5]ally p]*$ ^u ! summits & /eep flanks ( hills1 especially ( ! l[] spurs t skirt ! great m\nta9 ranges2 & ! rock+ ( ! hill-sites1 9 ,mallet's op9ion1 greatly aggravat$ ! natural effects ( ! %ock4 ,! /reets1 moreov]1 are /eep & n>r[1 sometimes only five feet1 & n (t5 m ?an fifte5 feet1 9 wid?2 & ! h\ses1 :5 %ak5 d[n1 fell aga9/ "o ano!r & ^u ^? b5ea? !m4 ,z ,dolomieu said ( ! great e>?quake 9 #aghc1 ! gr\nd 0 %ak5 d[n l a%es or s& laid ^u a table4 ,( ! total am\nt ( damage1 n ev5 ! r\ghe/ e/imate c be made4 ,! (ficial returns are cle>ly1 & no d\bt purposely1 defici5t1 & ob/acles 7 plac$ 9 ,mallet's way :5 he endeav\r$ to asc]ta9 ! numb]s ( p]sons kill$ & w\nd$4 ,tak+ only ! t[ns into acc\nt1 he calculat$ t1 out ( a total population ( #bjg1jjj1 ! numb] ( p]sons kill$ 0 #i1ehi1 & ( w\nd$ #a1cdc4h ,a few t[ns 7 m>k$ by an excessively high dea?-rate4 ,?us1 at ,montemurro1 #ejjj out ( #gjjb p]sons 7 kill$ & #ejj w\nd$2 at ,sapon>a1 #bjjj out ( #djaj 7 kill$2 &1 at ,polla1 m ?an #bjjj out ( a population ( less ?an #gjjj4 ,,g5]al ,,objects ,,( ,,inve/igation4 ,! pr9cipal objects ( ,mallet's inve/igation 7 to det]m9e ! position ( ! epic5tre & ! dep? ( ! seismic focus4 ,if1 9 ,fig4 #c1 ,f repres5ts ! seismic focus 7"h1 = conv5i5ce1 suppos$ to be a po9t71 ! v]tical l9e ,,fe w cut ! surface ( ! e>? 9 ! epic5tre ,e4#i ,! dott$ l9es repres5t circles drawn on ! surface ( ! e>? ) ,e z c5tre & pass+ ?r\gh ! places ,p & ,q4 ,illu/ration3 ,,fig4 #c4--;,diagram to illu/rate wave-pa? & angle ( em]g5ce4 ,:5 ! impulse caus+ ! e>?quake takes place at ! focus1 two ela/ic waves spread outw>ds f x 9 all directions ?r\gh ! e>?'s cru/4 ,! fir/ wave :i* rea*es a po9t ,p consi/s ( longitud9al vibrations1 t is1 ! p>ticle ( rock at ,p moves 9 a clos$ curve ) its long] axis 9 ! direction ,,fp4 ,mallet supposes ?is curve to be s elongat$ t x is practically a /raight l9e co9cid5t 9 direction ) ,,fp4 ,9 ! second or transv]sal wave1 ! vibration ( ! p>ticle at ,p takes place 9 a plane at "r angles to ,,fp4 ,^! vibrations ,mallet1 = 8 ma9 purpose1 neglects4 ,return+ to ! longitud9al wave1 ,mallet calls ! l9e ,,fp ! wave-pa? at ,p4 ,! direction ,,ep gives ! azimu? ( ! wave-pa?1 or its direction along ! surface ( ! e>?4 ,! angle ,,lpa1 or ,,epf1 he def9es z ! angle ( em]g5ce at ! po9t ,p4 ,if ,q be f>!r f ,e ?an ,p1 ! angle ,,eqf is less ?an ! angle ,,epf1 or ! angle ( em]g5ce dim9i%es z ! di/ance f ! epic5tre increases4 ,at ! epic5tre1 ! angle ( em]g5ce is a "r-angle2 at a great di/ance f ! epic5tre1 x is ne>ly z]o4 ,mallet argu$ t ! direction ( ! wave-pa? ,,fpa1 or its equival5ts1 ! horizontal direction ,,epl & ! angle ( em]g5ce ,,epf1 %\ld be discov]able f ! effects ( ! %ock at ,p4 ,! cracks 9 damag$ build+s1 he urg$1 w\ld be at "r angles to ! wave-pa? ,,fpa2 ov]turn$ monum5ts or gate-pill>s %\ld fall along ! l9e ,,epl1 ei!r t[>ds or f ! epic5tre accord+ to _! conditions ( support2 loose or slightly atta*$ bodies1 su* z ! /one balls surm\nt+ gate-pill>s1 %\ld be project$ ne>ly 9 ! direction ( ! wave-pa? ,,fpa1 & _! subsequ5t positions1 suppos+ ! balls n to h roll$1 %\ld give ! horizontal direction ,,epl ( ! wave-pa?1 & might1 9 "s circum/ances1 det]m9e ! angle ( em]g5ce & ! velocity ) :i* !y 7 project$4 ,i %all return to details lat] on4 ,= ! pres5t1 x is cle> t1 9 ! de/ruction wr\ght by ! e>?quake1 ,mallet expect$ to f9d ! mat]ials mo/ valuable = 8 purpose4 ,inde$1 s obvi\s did ?is mode ( exam9ation appe> to him1 t he c\ld n conceal 8 surprise at ! bl9dness ( 8 pr$ecessors4 ,!y seem1 he says1 to h be5 p]fectly unconsci\s t 9 ! fractur$ walls & ov]?r[n objects scatt]$ 9 all directions b5ea? _! eyes1 !y _h ! mo/ preci\s data = det]m9+ ! velocities & directions ( ! %ocks t produc$ !m4 ,,position ,,( ,,! ,,epic5tre4 ,mallet's ,me?od ( ,det]m9+ ! ,position ( ! ,epic5tre4--,9 _m cases ! exam9ation ( a damag$ build+ or ( an ov]?r[n body s]v$ m ?an "o purpose1 provid+ mat]ials = asc]ta9+ ! dep? ( ! seismic focus z well z ! position ( ! epic5tre4 ,= ! pres5t1 h[ev]1 x w be conv5i5t to consid] alone ! me?od by :i* ! latt] object 0 to be atta9$4 ,illu/ration3 ,,fig4 #d4--;,diagram to illu/rate ,mallet's me?od ( det]m9+ position ( epic5tre4 ,no?+ c\ld be simpl] ?an ! pr9ciple ( ! me?od propos$4 ,! horizontal direction ,,pl ( ! wave-pa? at any place ,p 7,fig4 #d71 :5 produc$ backw>ds1 mu/ pass ?r\gh ! epic5tre ,e2 & ! int]section ( ! directions at two places1 ,p & ,q1 mu/ !re=e give ! position ( ! epic5tre4 ,9 practice1 x is ( c\rse impossible to det]m9e ! direction ) v great accuracy1 & ,mallet !re=e f\nd x necess>y to make sev]al measurem5ts 9 e place1 & to visit all ! m important t[ns )9 & ne> ! meizoseismal area4 ,9 a ru9$ t[n !re are _m objects f :i* ! direction may be asc]ta9$1 ! mo/ important ( all1 accord+ to ,mallet1 be+ fissures 9 walls t are fractur$ b n ov]?r[n4 ,he reg>d$ su* fissures1 inde$1 z ! %eet-an*or1 z respects direction ( wave-pa?1 to ! seismologi/ 9 ! field1 & at lea/ ?ree out ( e f\r ( 8 det]m9ations ( ! direction 7 made by _! means4 ,if ! build+s are deta*$ & l>ge1 simple & symmetrical 9 =m1 well built & n too mu* injur$1 ! fissures 9 ! walls %\ld1 he argu$1 occur along l9es at "r angles to ! wave-pa?1 :e!r t pa? be p>allel or incl9$ to ! pr9cipal axis ( ! build+4 ,cracks 9 ! floors & ceil+s %\ld also be simil>ly direct$1 & provide evid5ce :i* ,mallet reg>d$ z only second 9 value to t giv5 by ! walls4 ,illu/ration3 ,,fig4 #e4--,plan ( ,ca!dral ,*ur* at ,pot5za4 7,mallet47 ,no build+ %[$ ! diff]5t k9ds ( evid5ce on :i* ,mallet reli$ z cle>ly z ! ca!dral *ur* at ,pot5za1 ! plan ( :i* is giv5 9 ,fig4 #e1 & ! v]tical section along its axis 9 ,fig4 #ab4 ,?is is a mod]n "w1 ne>ly #bjj feet long1 ) its axis direct$ ea/ & we/4 ,! walls are compos$ ( fairly good rubble masonry & brick2 & ! ar*es 9 ! nave & transepts1 ! semi-cyl9drical ro( & ! c5tral dome are made ( brick4 ,! fissures repres5t$ 9 bo? diagrams 7 drawn to scale by ! ca!dral ar*itect be=e ,mallet's arrival1 &1 z ! "w ( an unbiass$ obs]v]1 are ( special value4 ,mo/ ( ^? 9 ! ro(1 x w be se51 7 transv]se to ! axial l9e ( ! *ur*2 b !re 7 o!rs p>allel to ?is l9e1 "o 9 p>ticul> runn+ "r along ! s(fit ( ! nave & *ancel4 ,!re 7 also num]\s small fissures 9 ! dome1 due to local /ructural causes & !re=e ( v>y+ direction1 & a l>ge portion ( ! dome slipp$ we/w>d1 leav+ op5 fissures ( sev5 to eight in*es 9 wid?4 ,! mean direction ( ! wave-pa?1 z d$uc$ f n9e sets ( fissures1 none ( :i* diff]s m ?an f\r degrees f ! mean1 is ,w4 #b-a_/b ,s4 & ,e4 #b-a_/b ,n41 :i* corresponds precisely ) ! direction ( ?r[ on ! displac$ portion ( ! dome4 ,! great ea/ & we/ fissures 9 ! ar* ( ! nave & *ancel ,mallet attribut$ to a second %ock1 ( ! exi/5ce ( :i* !re is ample evid5ce4 ,illu/ration3 ,,fig4 #f4--;,fall5 gate-pill>s ne> ,sapon>a4 7,mallet47 ,next to fissures1 ,mallet made mo/ use ( ov]?r[n objects1 su* z ! two gate pi]s ne> ,sapon>a1 repres5t$ 9 ,fig4 #f4 ,!y 7 made ( rubble a%l> masonry1 ?ree feet squ>e & sev5 feet 9 height4 ,bo? 7 fractur$ clean (f at ! level ( ! gr\nd1 ! mort> be+ poor1 & fell 9 directions t 7 accurately p>allel1 indicat+ a wave-pa? t[>ds ,s4 #ci-a_/b;,e4 ,a few obs]vations 7 also made on project$ /ones1 fissures 9 ne>ly level gr\nd1 & ! sw++ ( lamps & *&eli]s2 b _! value 0 small1 except z corroboration ( ! m important evid5ce af=d$ by fissures 9 ! walls & ro(s ( build+s4 ,rem>ks on ,mallets ,me?od4--,x w\ld h be5 m difficult 9 ,mallet's day ?an x is n[1 to (f] objections to 8 me?od ( det]m9+ ! position ( ! epic5tre4 ,! focus1 z he 0 well aw>e1 c\ld n be a po9t1 &1 at places ne> ! epic5tre 7! v places :]e mo/ ( 8 obs]vations 7 made71 !re mu/ be rapid *anges ( direction due to ! arrival ( vibrations f diff]5t p>ts ( ! focus4 ,he records ! occurr5ce ( ! s-call$ vorticose %ocks at sev]al places1 ?\gh he attributes !m to ano!r cause4 ,p]haps ! be/ kn[n example ( su* a %ock is t :i* has be5 s well illu/rat$ by ! late ,pr(essor ,sekiya's model ( ! motion ( an e>?-p>ticle dur+ ! ,japanese e>?quake ( ,janu>y #ae?1 #ahhg4 ,! motion 9 ?is case 0 s complicat$ t ! model 01 = simplicity1 made 9 ?ree p>ts1 ! fir/ ( :i* alone is repres5t$ 9 ,fig4 #g4aj ,x is cle> t 9 su* an e>?quake1 ,mallet's me?od w\ld utt]ly fail 9 giv+ def9ite results4 ,:ile ?is %ock 0 "o ( great complexity1 ano!r ,japanese e>?quake1 t ( ,june #bj?1 #ahid1 0 unusually simple 9 "*4 ,! movem5t at ,tokio consi/$ ( "o v prom95t oscillation ) a total range ( #gc mm4 or #b4i in*es 9 ! direction ,s4 #gj ,w42 ! vibrations :i* prec$$ & foll[$ x be+ comp>atively small4 ,mo/1 if n all1 ( ! damage caus$ by ! e>?quake mu/ h be5 due to ?is great oscillation2 & yet ! cyl9drical /one-lamps s common 9 ,japanese g>d5s 7 f\nd by ,pr(essor ,omori to h fall5 9 _m diff]5t directions4 ,tak+ only ^? :i* _h circul> bases1 tw5ty-n9e 7 ov]?r[n 9 directions betwe5 nor? & ea/1 sixte5 betwe5 ea/ & s\?1 eighty-"o betwe5 s\? & we/1 & f\rte5 betwe5 we/ & nor?4#aa ,fig4 #h repres5ts ,pr(essor ,omori's results graphically1 ! l9e drawn f ,o to any po9t be+ proportional to ! numb] ( lamps :i* fell 9 directions betwe5 #g-a_/b on ei!r side ( ! l9e4 ,illu/ration3 ,,fig4 #g4--,model to illu/rate ! motion ( an e>?-p>ticle dur+ an e>?quake4 7,sekiya47 ,illu/ration3 ,,fig4 #h4--,plan ( directions ( fall ( ov]turn$ /one-lamps at ,tokio dur+ ! e>?quake ( #ahid4 ,x w be se5 f ?is figure t mo/ ( ! /one lamps fell 9 directions betwe5 we/ & s\?-we/1 & x is rem>kable t ! mean direction ( fall is ,s4 #gj ,w41#ab :i* is exactly ! same z t ( ! great oscillation4 ,some:at simil> results 7 obta9$ by ?is able seismologi/ at diff]5t places affect$ by ! great ,japanese e>?quake ( #ahia 7,figs4 #dc & #dd71 & ! /udy ( ! app>5t directions obs]v$ dur+ ! ,h]e=d e>?quake ( #ahif leads to ! same conclusion4 ,x ?us appe>s t an isolat$ obs]vation may give a result v diff]5t f ! true direction4 ,inde$1 if we may judge f ,pr(essor ,omori's measurem5ts 9 #ahid1 ! *ance t a s+le direction may be )9 five degrees ( ! mean direction is ab\t #a 9 #i4 ,b1 on ! o!r h&1 x is equally cle> f ^! & o!r obs]vations t ! mean ( a l>ge numb] ( measurem5ts w give a result t agrees v closely ) ! true direction4 ,"o o!r po9t may be allud$ to be=e leav+ ,pr(essor ,omori's int]e/+ obs]vations4 ,x w\ld seem1 f ! li/ t he gives1 t he ex]cis$ no selection 9 8 measurem5ts1 b cont9u$ measur+ ! direction ( e fall5 lamp indiff]5tly until he _h obta9$ suffici5t records = 8 purpose4 ,n[1 if ! numb] ( fall5 lamps at 8 disposal _h be5 small1 say #ab in/ead ( #add1 ! mean obs]v$ direction w\ld probably h diff]$ f ! direction giv5 f ! seismograph4#ac ,b1 on ! o!r h&1 a prelim9>y survey )\t any actual measurem5ts w\ld h reveal$ at once ! pr$om9ant direction ( ov]?r[1 & a fairly accurate result might h be5 obta9$ by neglect+ discordant directions & tak+ ! mean ( ^? only :i* appe>$ to agree ) ! m5tally det]m9$ av]age4 ,?is1 inde$1 appe>s to h be5 ! c\rse foll[$1 m or less unconsci\sly1 by ,mallet 9 8 ,neapolitan "w4 ,:5 ! obs]v]1 he says1 fir/ ent]s ^u "o ( ^? e>?quake-%ak5 t[ns1 he f9ds himself 9 ! mid/ ( utt] confusion4 ,! eye is bewild]$ by 'a city become an heap4' ,he w&]s ov] masses ( dislocat$ /one & mort>1 ) timb]s half buri$1 pro/rate1 or /&+ />k up aga9/ ! light1 & is appall$ by spectacles ( desolation4444 ,h\ses seem to h be5 precipitat$ to ! gr\nd 9 e direction ( azimu?4 ,!re seems no gov]n+ law1 nor any indication ( a prevail+ direction ( ov]turn+ =ce4 ,x is only by fir/ ga9+ "s comm&+ po9t1 :5ce a g5]al view ov] ! :ole field ( ru9 c be _h1 & obs]v+ its places ( greate/ & lea/ de/ruction1 & !n by pati5t exam9ation1 compass 9 h&1 ( _m details ( ov]?r[1 h\se by h\se & /reet by /reet1 analys+ ea* detail & comp>+ ! results1 z to ! direction ( =ce1 t mu/ h produc$ ea* p>ticul> fall1 ) ^? previ\sly obs]v$ & comp>$1 t we at l5g? p]ceive1 once = all1 t ?is app>5t confusion is b sup]ficial4 ,illu/ration3 ,,fig4 #i4--,meizoseismal area ( ,neapolitan e>?quake4 7,mallet47 ,mallet's ,det]m9ation ( ! ,epic5tre4--,)9 ! ?ird isoseismal l9e ,mallet made altoge!r #agg measurem5ts ( ! direction ( ! wave-pa? at #gh places4 ,^! are plott$ on 8 great map ( ! e>?quake2 b1 ow+ to ! small scale ( ,fig4 #i1 x is only possible to repres5t1 by means ( %ort l9es1 ! mean or mo/ tru/wor?y direction at ea* place4#ad ,produc+ ^! directions backw>ds1 he f\nd t ^? at sixte5 places pass$ )9 five hundr$ y>ds ( a po9t :i* is practically co9cid5t ) ! village ( ,caggiano2 ^? at sixte5 o!r places pass$ )9 "o geographical mile 7#a4aec /atute miles7 ( ?is po9t2 ! directions at sixte5 m places )9 two & a half geographical miles2 :ile ^? at twelve places pass$ ?r\gh po9ts n m ?an five geographical miles f ,caggiano4 ,z ! direction ( ! %ock at places ne> ! epic5tre mu/ h be5 influ5c$ by ! m]e size ( ! focus1 ?is approximate co9cid5ce is c]ta9ly rem>kable1 & !re c be little d\bt1 ,i ?9k1 t ! epic5tre1 or1 at any rate1 an epic5tre mu/ h be5 situat$ n f> f ! position assign$ to x by ,mallet's labori\s obs]vations4 ,exi/5ce ( ,two ,epic5tres4--,x is difficult1 h[ev]1 to realise t ! impulse at ! focus correspond+ to ,mallet's epic5tre 0 ! orig9 ( all ! de/ruction ( life & prop]ty t occurr$4 ,! position ( ! epic5tre close to ! nor?-we/ b\nd>y ( ! meizoseismal area1 ! extraord9>y ext5sion ( t area t[>ds ! s\?-ea/1 & especially ! great loss ( life at ,montemurro & ! adjo9+ t[ns1 c h>dly be acc\nt$ = 9 ?is mann]4 ,mallet himself recognis$ t ^! facts requir$ explanation1 & he sugge/$ t ! situation & "* ( ! t[ns 7 9 "p responsible = _! ru91 & ! physical /ructure ( ! c\ntry = ! c\rse ( ! isoseismal l9es4 ,b ! comp>ative escape ( places mu* ne>] ,caggiano1 & ! wide ext5t ( ! meizoseismal area1 embrac+ _m t[ns & villages ( v>i$ "* & site & _m diff]5t surface-features1 po9t unmi/akably to a diff]5t explanation4 ,illu/ration3 ,,fig4 #aj4--;,di/ribution ( dea?-rate )9 meizoseismal area ( ,neapolitan e>?quake4 ,"o clue to ! solution ( ! problem is af=d$ by ! seismic dea?-rate ( ! damag$ t[ns4 ,f a table giv5 by ,mallet 7vol4 ii4 pp4 #afb-afc71 we "k ! population be=e ! e>?quake ( ! diff]5t communes 9 ! prov9ce ( ,basilicata1 & ! loss ( life 9 ea* due to ! %ock2 & f ^! figures we c f9d ! p]c5tage ( dea?s at ne>ly e place ( importance4 ,z w be se5 f ,fig4 #aj1 x v>ies f sev5ty-"o at ,montemurro & fifty at ,sapon>a d[n to less ?an "o at all ! places m>k$ to :i* figures are n atta*$4 ,!re is ?us a gr\p ( places1 ) its c5tre ne> ,montemurro1 :]e ! loss ( life f> exce$$ t 9 ! surr\nd+ c\ntry2 & also a slightly less-m>k$ gr\p1 ) its c5tre ne> ,polla1 9 ! nor?-we/ ( ! meizoseismal area2 :ile 9 ! int]m$iate region ! dea?-rate 0 inv>iably small4 ,too mu* /ress %\ld n be laid ^u ! exact figures1 = !re 7 no d\bt local conditions t affect$ ! dea?-roll4 ,b x seems cle> t "o focus 0 situat$ n f> f ,montemurro2 :ile ! nor?-we/]ly gr\p ( places1 comb9$ ) ,mallet's obs]vations on ! direction1 po9t to a second focus ne> ,polla1 ab\t tw5ty-f\r miles to ! nor?-we/4 ,x w be se5 9 a lat] section t ! obs]vations on ! nature ( ! %ock also imply ! exi/5ce ( a d\ble focus4 ,,dep? ,,( ,,! ,,seismic ,,focus4 ,mallet's ,me?od ( ,det]m9+ ! ,dep? ( ! ,focus4--,9 asc]ta9+ ! position ( ! epic5tre1 ,mallet's "w 0 rem>kable only = ! novelty ( ! me?od employ$ by him2 b1 9 8 attempt to calculate ! dep? ( ! seismic focus1 he 0 break+ new gr\nd4 ,t ! dep? mu/ be comp>atively small _h already be5 recognis$1 & 0 inde$ obvi\s f ! limit$ area di/urb$ by ne>ly e e>?quake4 ,no "o1 h[ev]1 _h tri$ to e/imate ! dep? 9 miles2 & x is impossible n to sympa?ise ) ,mallet :ile he accumulat$ 8 obs]vations ) fev]i% activity & subject$ !m to ! fir/ r\gh exam9ation ev5 if "o _c %>e 8 confid5ce t he _h succe$$ 9 measur+ ! dep? 9 miles & y>ds ) ! c]ta9ty t belongs to an ord9>y geodetic op]ation4 ,! me?od employ$ by him = ! purpose is no less simple !oretically ?an t us$ = locat+ ! epic5tre4 ,if ! position ( ! latt] 7,e7 is kn[n1 "o accurate measurem5t ( ! angle ( em]g5ce ,,epf1 at any o!r po9t ,p w\ld be suffici5t to fix ! dep? ( "s po9t )9 ! focus ,f 7,fig4 #aa74 ,"h1 aga91 ,mallet reli$ *iefly on fissures 9 walls t 7 fractur$ b n ov]?r[n4 ,9 detail1 ^! fissures are ne>ly always jagg$ or s]rat$1 = !y t5d to foll[ ! l9es ( jo9ts r ?an break ?r\gh ! solid /one1 ?\gh !y sometimes trav]se bricks & mort> alike4 ,b ! g5]al c\rse ( ! fissures1 he urg$1 w\ld be at "r angles to ! wave-pa?1 & _! incl9ation to ! v]tical %\ld be equal to ! angle ( em]g5ce4 ,illu/ration3 ,,fig4 #aa4--;,diagram to illu/rate ,mallet's me?od ( det]m9+ dep? ( seismic focus4 ,9 obta9+ measurem5ts ( ?is angle1 ! build+s to be *os5 are ^? ( l>ge size1 ) few w9d[s or o!r ap]tures1 & ) walls made ( brick or small %ort-b$d$ /ones4 ,! ca!dral-*ur* at ,pot5za p]haps satisfies ^! conditions m closely ?an any o!r /ructure exam9$ by ,mallet4 ,! plan ( ! fissures 9 ! walls & ro( has be5 giv5 9 ,fig4 #e1 & ,fig4 #ab repres5ts ! fissures ,9 ! v]tical section along ! axial l9e & look+ nor?1 z drawn by ! ca!dral ar*itect4 ,f ^! fissures ,mallet calculat$ ! mean angle ( em]g5ce at ,pot5za to be #bc #g'4 ,! di/ance ( ,pot5za f ,caggiano be+ sev5te5 miles1 & ! height ( ! =m] be+ #b1ehj feet1 ! dep? ( ! focus result+ f ?is obs]vation alone w\ld be #f-c_/d miles bel[ ! level ( ! sea4 ,illu/ration3 ,,fig4 #ab4--,v]tical section ( ,ca!dral ,*ur* at ,pot5za4 7,mallet47 ,objection to ,mallet's ,me?od4--,! weake/ po9t 9 ,mallet's me?od is probably 8 assumption t ! wave-pa?s are /raight l9es ext5d+ outw>d f ! focus4 ,ev5 if ! dep? ( ! focus is n m ?an a few miles1 ! waves mu/ trav]se rocks ( v>y+ d5sity & ela/icity1 &1 at e b\nd+ surface1 !y mu/ und]go refraction4 ,if ! rocks are s con/itut$ t ! velocity ( ! e>?-waves 9 !m increases ) ! dep?1 !n ! wave-pa?s mu/ be b5t cont9ually outw>ds f ! v]tical1 s t ! angle ( em]g5ce at ! surface may be consid]ably less ?an x w\ld h be5 ) a con/ant velocity ?r\gh\t4 ,9 ?is case1 ! actual dep? w be great]1 p]haps mu* great]1 ?an ! calculat$ dep?4 ,= in/ance1 if ! angle ( em]g5ce at ,pot5za 7 dim9i%$ only #e by refraction1 ! calculat$ dep? ( ! focus w\ld be too small by #a-c_/d miles4 ,mallet's ,e/imate ( ! ,dep? ( ! ,focus4--,mallet measur$ ! angle ( em]g5ce at tw5ty-six places1 ! mean angle 7i4e4 ! mean ( ! greate/ & lea/ obs]v$ angles7 v>y+ f #gb at ,vietri di ,pot5za & #gj at ,p]tosa1 :i* are ab\t two miles f ! calculat$ epic5tre1 to #aa-a_/b at ,sal]no1 di/ant ab\t #dj miles4 ,fig4 #ac reproduces "p ( ! diagram on :i* he plott$ ! mean angle ( em]g5ce at diff]5t places4 ,! horizontal l9e repres5ts ! level ( ! sea1 & ! v]tical l9e "o pass+ ?r\gh ! epic5tre & focus1 call$ by ,mallet ! seismic v]tical4 ,! l9es on ! left-h& side repres5t ! comm5c+ wave-pa?s 7assum$ /raight7 to ! obs]v+ /ations situat$ to ! we/w>d ( ! m]idian ?r\gh ! epic5tre1 ^? on ! "r-h& side correspond+ to places to ! ea/w>d ( ! same m]idian4 ,small horizontal m>ks are add$ to indicate ! dep? 9 miles bel[ ! level ( ! sea4 ,illu/ration3 ,,fig4 #ac4--;,diagram ( wave-pa?s at seismic v]tical ( ,neopolitan e>?quake4 7,mallet47 ,x w be se51 f ?is diagram1 t all ! wave-pa?s />t f ! seismic v]tical at dep?s betwe5 ?ree & n9e miles2 b ! po9ts ( dep>ture are clu/]$ ?ickly )9 a portion1 ! l5g? ( :i* is ab\t #c-a_/b miles & ! mean dep? ab\t #f-a_/b miles4 ,s great 0 ,mallet's confid5ce 9 ^! calculations t he assigns ! div]g+ orig9 ( ! wave-pa?s to diff]5t po9ts ( ! focus1 & ?us concludes t1 :ile ! mean dep? ( ! focus 0 ab\t #f-a_/b miles1 its dim5sions 9 a v]tical direction did n exce$ #c-a_/b miles4 ,h[ f> ,mallet's results %\ld be accept$ z correct1 x is difficult to say 9 our ignorance ( ! con/itution ( ! e>?'s int]ior4 ,!re c be no d\bt t ! focus 0 ( consid]able size1 & t1 9 consequ5ce1 ! wave-pa?s w\ld div]ge f diff]5t po9ts ( x4 ,b t ea* wave-pa? %\ld actually int]sect ! focus1 & s enable its magnitude to be det]m9$1 w\ld surely involve an approa* to "s law connect+ ! direction ( a wave-pa? ) ! dep? ( its own orig91 & no su* law seems to be asc]ta9able4 ,nor c ! limitation ( ^! app>5t orig9s betwe5 c]ta9 dep?s be held to argue t ! focus1 or any "p ( x1 0 equally conf9$1 = ! wave-pa?s w\ld to a great ext5t be simil>ly refract$4 ,i fe> t ! only conclusions t we c ) safety draw f ,mallet's admirable "w are t 8 figures indicate ! ord] ( magnitude bo? ( ! v]tical dim5sions & ( ! mean dep? ( ! focus4 ,,nature ,,( ,,! ,,%ock4 ,x is n easy to =m any precise image ( ! e>?quake z x appe>$ to ! t]rifi$ witnesses )9 ! meizoseismal area4 ,to m9ds unbalanc$ by ! sudd5ness ( ! %ock & by ! cra% ( fall+ h\ses1 actuat$ too by ! int5se ne$ ( safety1 ! m]e succession ( ev5ts mu/ h pres5t$ b little int]e/4 ,! int]val ( two mon?s t elaps$ betwe5 ! occurr5ce ( ! e>?quake & its inve/igation 0 also unfav\rable to ! collection ( accurate acc\nts f a wond]-lov+ p4 ,only "o feature1 !re=e1 /&s out cle>ly 9 ! few records giv5 by ,mallet--namely1 ! division ( ! %ock into two di/9ct p>ts4 ,9 ! c5tral di/rict1 ?is division is p]haps less app>5t ?an else:]e4 ,at ,polla1 = in/ance1 :i* lies close to ! nor?-we/ epic5tre1 ! fir/ w>n+ 0 giv5 by a ru%+ s\nd2 almo/ in/antly1 & :ile x 0 yet he>d1 came a /rong subsultory or up-&-d[n movem5t1 succe$$ aft] a few seconds1 b )\t any int]val1 by an undulatory motion4 ,at ,pot5za1 :i* is n f> f ! same epic5tre b a few miles outside ! meizoseismal area1 ! sep>ation 0 m pron\nc$4 ,accord+ to "o obs]v]1 ! fir/ movem5t 0 f we/ to ea/2 &1 )9 a second or two aft]w>ds1 !re 0 a less viol5t %ock 9 a transv]se direction1 foll[$ imm$iately by a %ak+ 9 all directions1 call$ by ! ,italians vorticose4 ,naples lies sixty-n9e miles f ! nor?-we/ epic5tre1 & "h m accurate obs]vations c\ld be made4 ,dr4 ,l>dn]1 well kn[n fifty ye>s ago z a writ] ( sci5tific works1 describes ! fir/ movem5t felt !re z a %ort1 j>r+1 horizontal oscillation1 t made all doors & w9d[s rattle1 & ! floors & furniture creak4 ,?is ceas$1 & aft] an int]val t seem$ b a few seconds 0 r5ew$ ) great] viol5ce1 &1 he ?\ght1 ) a di/9ctly undulatory movem5t1 'l t 9 ! cab9 ( a small vessel 9 a v %ort *opp+ sea4' ,9 five o!r e>?quakes /udi$ 9 ?is volume1 ! sep>ation ( ! %ock into two p>ts 0 a well-m>k$ ph5om5on4 ,9 ! ,neapolitan e>?quake1 ! sep>ation 0 s di/9ct t ,mallet took "s pa9s to acc\nt = its orig94 ,he reg>d$ x 9 e case z due to ! reflection or refraction ( ! e>?-waves by und]ly+ rocks1 ?\gh he does n expla9 :y ! reflect$ or refract$ wave %\ld be m int5se ?an t transmitt$ directly4 ,i %all ref] to ! subject 9 great] detail :5 describ+ ! ,&alusian1 ,*>le/on1 ,rivi]a1 & ,h]e=d e>?quakes4 ,= ! pres5t1 x may be suffici5t to urge t ! d\ble %ock _c h be5 due to ! sep>ation ( ! orig9al waves by und]gr\nd reflection or refraction1 = !n ! second "p %\ld h be5 g5]ally ! weak]2 nor to ! succession ( longitud9al & transv]se waves1 =1 9 t case1 e e>?quake-%ock %\ld be duplicat$4 ,! only rema9+ supposition is t !re 0 a second impulse occurr+ ei!r 9 ! same or 9 a diff]5t focus4 ,:i* alt]native %\ld be adopt$1 ! evid5ce on ! nature ( ! %ock is too scanty to det]m9e4 ,! defect is1 h[ev]1 supplem5t$ by ,mallet's obs]vations on ! direction ( motion2 =1 at _m places )9 & ne> ! meizoseismal area1 he met ) ! cle>e/ signs ( a d\ble direction4 ,sometimes ?is 0 app>5t to ! s5ses ( ! obs]v]2 9 o!r cases1 damag$ build+s pres5t$ two sets ( fissures4 ,at ,la ,sala & ne> ,padula1 ! fir/ movem5t 0 r\ghly ea/ & we/1 ! second nor? & s\?4 ,at ,molit]no1 !re 0 evid5ce ( a subord9ate %ock at "r angles to ! *ief "o2 9 ! neighb\rhood ( ,tramutola1 its direction 0 f ab\t ,e4 #cj ,s4 ,9 ^! & o!r cases1 ,mallet saw ! effects ( e>?quake-e*oes2 b ! und]gr\nd reflection ( e>?-waves w\ld give rise to ! second "p ( ! %ock1 n ! fir/ z at ,la ,sala & ,padula4 ,moreov]1 ! second>y directions1 ?\gh !y are seldom record$ accurately1 po9t ne>ly to an epic5tre n f> f ,montemurro4 ,! obs]vations on ! nature & direction ( ! d\ble %ock ?us confirm ! conclusion1 d]iv$ f ! di/ribution ( ! seismic dea?-rate1 t !re 7 two deta*$ foci1 "o ne> ,polla & ! o!r ne> ,montemurro4 ,?is seems to be ! be/ explanation ( ! facts record$ by ,mallet4 ,!re is1 h[ev]1 a possible difficulty t %\ld n be ov]look$--namely1 ! app>5tly slight influ5ce ( ! ,montemurro focus on ! mean direction ( ! %ock 7,fig4 #i74 ,at a few places1 ( c\rse1 ! mean direction passes ?r\gh bo? epic5tres2 at "s o!rs1 z we h se51 "o ( ! two obs]v$ directions po9ts t[>ds ! ,montemurro epic5tre4 ,x is n impossible1 also1 t ,mallet1 aft] ! fir/ few days' "w1 may occasionally h q unconsci\sly select$ & measur$ ^? fissures f ! maze pres5t$ to him :i* agre$ mo/ closely ) 8 e>ly impressions obta9$ f ! neighb\rhood ( ,polla4 ,b1 = places ne>] ,polla ?an ,montemurro 7& ^! =m ! majority ( ^? visit$ by ,mallet71 ! probable explanation ( ! difficulty is t ! ,montemurro focus 0 n s deep z ! ,polla focus4 ,?is1 z w appe> m fully 9 ! next *apt]1 w\ld acc\nt = ! comp>atively great int5sity 9 ! imm$iate neighb\rhood ( ,montemurro & = its rapid decl9e outw>ds2 & x receives "s support f an isolat$ ref]5ce by ,mallet to two angles ( em]g5ce at ,padula1 "o ( #be f ! nor?1 & ! o!r ( #h or #aj 9 ! p]p5dicul> walls4 ,,elem5ts ,,( ,,! ,,wave-,,motion4 ,! elem5ts ( ! wave-motion1 z m5tion$ 9 ! introductory *apt]1 are f\r 9 numb]1 namely1 ! p]iod1 amplitude1 maximum velocity1 & maximum accel]ation4 ,if any two ( ^! are kn[n = ea* vibration--& ! fir/ two are n[ giv5 by e accurately con/ruct$ seismograph--! o!rs c be det]m9$ if ! vibrations foll[ ! law ( simple h>monic motion4#ae ,amplitude4--,to asc]ta9 ! amplitude1 ,mallet _h to rely *iefly on ! fissures made 9 v inela/ic walls4 ,if ! p>ts into :i* su* a wall are fractur$ are free to move1 & yet1 be+ inela/ic1 oblig$ to rema9 9 ! f>!/ position to :i* !y are c>ri$ by ! wave1 ! di/ance trav]s$ by ! c5tre ( gravity ( "o ( ! displac$ p>ts %\ld give a rude approximate measure ( ! horizontal amplitude ( ! e>?-wave4 ,at ,c]tosa1 ne> ,padula1 he ?us f\nd ! amplitude to be ab\t #d in*es1 at ,s>coni ab\t #d-c_/d in*es1 & at ,tramutola ab\t #d-a_/b in*es4 ,f some:at simil> evid5ce1 ! amplitude at ,polla appe>s to h be5 ab\t #b-a_/b or #c in*es2 &1 f ! oscillation ( a susp5d$ clock or wat* on a r\gh wall1 ab\t #c-a_/b in*es at ,la ,sala & #a-c_/d in*es at ,b>ielle4 ,) ! exception ( ,b>ielle1 ^! places lie ne>ly on a /raight l9e pass+ ?r\gh ,mallet's epic5tre1 & he gives ! foll[+ table1 %[+ an increase 9 amplitude ) ! di/ance f ! epic5tre3-- ,polla4 ,la ,sala4 ,c]tosa4 ,tramutola4 ,s>coni4 ,di/ance 9 miles #d4j #ac4d #ai4j #bc4h #cj4h ,amplitude 9 in*es #b-a_/b #c-a_/b #d #d-a_/b #d-c_/d ,! exi/5ce ( ! ,montemurro focus mu/1 h[ev]1 complicate any relation t may connect ^! two quantities4 ,maximum ,velocity4--,! means at ,mallet's disposal = det]m9+ ! maximum velocity 7 m num]\s ?an ^? available = ! amplitude4 ,f ! dim5sions ( a fall5 column ( regul> =m we %\ld be able1 he rem>ks1 to f9d an inf]ior limit to ! value ( ! maximum velocity2 :ile a sup]ior limit at ! same place may be obta9$ f "s o!r regul> solid :i* escap$ be+ ov]?r[n4 ,if a loose body is project$ by ! %ock at a place :]e ! angle ( em]g5ce is kn[n1 ! horizontal & v]tical di/ances trav]s$ by ! c5tre ( gravity w give ! velocity ( projection4 ,or1 if two su* bodies are project$ at "o place1 ! same measures = ea* w z a rule give bo? ! angle ( em]g5ce & ! velocity ( projection4 ,a ?ird me?od dep5ds on ! fissur+ ( walls1 suppos+ t we "k ! =ce p] unit surface :i*1 :5 sudd5ly appli$1 is j suffici5t to produce fracture4 ,sometimes m ?an "o me?od mu/ be appli$ to ! same object4 ,! two gate-pill>s ne> ,sapon>a 7illu/rat$ 9 ,fig4 #f7 = example requir$ a horizontal velocity ( #e4dh feet p] second to fracture !m1 & an additional velocity ( #e4ad feet p] second to ov]?r[ !m4 ,! well-kn[n seismologi/1 ,pr(essor ,milne1 urges v =cibly t measurem5ts obta9$ f ! projection or fall ( columns are unreliable1 = ! e>li] tremors might cause ! columns to rock1 & _! ov]?r[ ne$ n !re=e measure accurately ! maximum velocity ( ! critical vibration4#af ,!re c be no d\bt t ,mallet 0 alive to ?is difficulty1 ?\gh he may n h appreciat$ x at its full value4 ,?us1 at ! ,c]tosa de ,/4 ,lor5zo1 a mona/]y ne> ,padula1 a vase project$ f ! summit ( a sl5d] gate-pi] impli$ a velocity ( #ba-c_/d feet p] second2 & ! excess ( ab\t #h-a_/d feet p] second above ! velocity det]m9$ by o!r means is attribut$ by him to ! oscillation ( ! pi] itself4 ,h[ f> ?is s\rce ( error ent]s into o!r obs]vations x is impossible to say2 b x is wor? notic+ h[ closely ! velocities obta9$ by diff]5t me?ods agree ) "o ano!r4 ,?us1 f projection only1 we h velocities ( #aa4e feet p] second at ! ,c]tosa1 #aa4h at ,molit]no & ,montic*io1 #ad4h at ,tramutola1 & #i4h feet p] second at ,s>coni2 f ov]?r[ alone1 #aa4j feet p] second at ,viscolione1 ne> ,sapon>a1 & #aa4f at ,b>ielle2 f ov]?r[ & projection1 #ac4b feet p] second at ,polla & #ab4i at ,padula2 f fracture & ov]?r[1 #ab4c feet p] second at ,pot5za & #ae4f at ,sapon>a4 ,! comp>atively high values at ,tramutola & ,sapon>a1 ,mallet imag9$ might be due to ! oscillation ( ! hills on :i* ^! t[ns are built4 ,he !re=e omits !m 9 calculat+ ! mean maximum velocity1 :i* he f9ds to be twelve feet p] second1 a velocity less ?an t ) :i* a man rea*es ! gr\nd :5 he jumps (f a table4 ,) ! same omissions1 ,mallet gives ! foll[+ table1 %[+ a g5]al decrease 9 ! maximum velocity z ! di/ance f 8 epic5tre increases3-- ,polla4 ,padula4 ,c]tosa4 ,molit]no4 ,viscolione4 ,s>coni4 ,di/ance 9 miles #d4j #ai4j #ai4j #bi4d #cj4j #cj4h ,max4 vel4 9 ft4 p] sec4 #ac4b #ab4i #aa4e #aa4h #aa4j #i4h ,on ! nor? side ( ! epic5tre we h3-- ,pot5za4 ,montic*io4 ,b>ielle4 ,di/ance 9 miles #ag4c #bg4a #bh4b ,max4 vel4 9 ft4 p] sec4 #ab4c #aa4h #aa4f ,x is n impossible t ! high calculat$ velocities at ,tramutola & ,sapon>a 7 p>tly or entirely due to ! impulse f ! ,montemurro focus4 ,if we take #d in*es = ! amplitude ( ! l>ge/ v>iation1 & #ab feet p] second = ! maximum velocity1 & assume ! motion to h be5 ( a simple h>monic "*1 ! p]iod ( a complete vibration w\ld be less ?an "o-fif? ( a second4#ag ,n[1 we "k f seismographic records t ?is is r\ghly ! p]iod ( ! small tremors t =m ! comm5cem5t ( an e>?quake-%ock1 :ile ! p]iod ( ! l>ge/ vibrations may am\nt to z mu* z "o or two seconds4 ,we may !re=e conclude ei!r t ! assumption ( simple h>monic motion is incorrect1 or t ! maximum velocity is too great1 or m probably p]haps t ! amplitude is too small4#ah ,,s\nd-,,ph5om5a4 ,mallet 0 "o ( ! fir/ seismologi/s to realise ! significance ( ! e>?quake-s\nd2 & he att5d$ closely to ! subject1 ?\gh f9d+ ! s\nd ev5 m elusive ( precise obs]vation ?an ! %ock4 ,! *ief result obta9$ by him 0 ! comp>ative smallness ( ! area ov] :i* ! s\nd 0 he>d4 ,he e/imates x at little m ?an #c1cjj squ>e miles1 or ab\t "o-twelf? ( t ov] :i* ! %ock 0 felt4 ,x ext5ds nor? & s\? f ,melfi to ,lagonegro1 & ea/ & we/ f ,monte ,peloso to ,du*essa & ,s5]*ia4 ,! s\nd 0 ?us conf9$ to ! region 9 :i* ! %ock atta9$ its mo/ de/ructive "*4 ,t[>ds ! nor? & s\? ends ( ! s\nd-area all obs]v]s describ$ ! s\nd z a l[1 grat+1 heavy1 sigh+ ru%1 la/+ f tw5ty to sixty seconds1 "s add+ t x 0 also ( a rumbl+ nature4 ,ne> ! c5tre & ! ea/ & we/ b\nd>ies1 ! s\nd 0 di/9ctly m rumbl+2 x 0 %ort] 9 duration1 & began & end$ m abruptly4 ,! e>?quake1 ,mallet rem>ks1 began ev]y:]e ) tremors2 ! s\nds g5]ally arriv$ at ! same "t2 ! app>5t direction ( movem5t ( ! tremul\s oscillations appe>$ rapidly to *ange1 & /ill m rapidly to increase 9 amplitude2 !n ! great %ove ( ! de/ructive %ock arriv$1 9 "s places r be=e1 9 "s a little aft]1 ! mom5t ( l\de/ s\nd1 & x di$ away sudd5ly 7i4e41 ) extreme rapidity7 into tremors aga91 b diff]+ 9 direction f t ( ! great %ock itself4#ai ,! e>?quake-s\nd w be describ$ m fully 9 ! *apt] deal+ ) ! ,h]e=d e>?quake ( #ahif1 9 :i* x w be f\nd t ! ph5om5a record$ by ,mallet are equally *>act]i/ic ( ! slight] %ocks felt 9 ?is c\ntry4 ,,velocity ,,( ,,! ,,e>?-,,waves4 ,9 #aheg little 0 kn[n ab\t ! velocity ( e>?quake-waves4 ,exp]im5ts _h be5 made by ,mallet himself 9 #ahdi 9 ! neighb\rhood ( ,dubl94 ,^! gave #hbe feet p] second = ! velocity 9 d5se wet s&1 #a1cjf feet p] second 9 discont9u\s granite1 & #a1ffe feet p] second 9 m solid granite4#bj ,! only e>?quake = :i* ! velocity _h be5 calculat$ 0 ! ,rh5i% e>?quake ( #ahdf1 ! value asc]ta9$ by ,s*midt be+ #a1cgf ,fr5* feet1 or #a1dff ,engli% feet1 p] second4 ,! accurate public measurem5t ( "t1 :i*1 z ,mallet rem>ks1 is "o ( ! sure/ indications ( advanc+ civilisation1 01 h[ev]1 unkn[n 9 ! k+dom ( ,naples2 & 8 attempt 0 !re=e fett]$ by ! r>ity ( precise e/imates ( ! "t ( occurr5ce4 ,?r\gh\t ! :ole di/urb$ area only six good records c\ld be obta9$1 & ?ree ( ^! 7at ,vietri di ,pot5za1 ,atella1 & ,naples7 7 d]iv$ f /opp$ clocks1 witnesses ( r d\btful value4 ,at ,montef]mo & ,b>ielle ! "t 0 at once read f a wat*1 & at ,melfi f an accurate pocket *ronomet]4 ,! times giv5 v>y f #i;h4 #eim4 #afs4 ,p4,m4 7,naples mean "t7 at ,vietri di ,pot5za to #aj;h4 #gm4 #dds4 at ,naples4 ,all[+ = ! suppos$ *ange ( direction by refraction at ! ,monte ,/4 ,angelo range on ! way to ,naples1 ,mallet f9ds ! mean surface velocity to be #ghg feet p] second4 ,omitt+ ! ,naples record1 & tak+ acc\nt ( ! calculat$ dep? ( ! focus1 ! mean velocity becomes #hjd feet p] second4 ,,m9or ,,%ocks4 ,a great e>?quake r>ely1 if ev]1 occurs )\t "s prep>ation 9 ! =m ( a m>k$ increase ( seismic activity4 ,p]rey records sev]al %ocks dur+ ! two ye>s #ahef-eg t 7 felt at places z f> ap>t z ,naples1 ,melfi1 & ,cos5za4 ,on ,decemb] #g?1 #aheg1 a slight %ock1 ) a report f b5ea? l ! explosion ( a m9e1 0 felt at ,pot5za4 ,!n came ! great e>?quake on ,decemb] #af?1 at ab\t #aj ,p4,m4 ,?is 0 foll[$ by num]\s aft]-%ocks--h[ num]\s x is impossible to say1 = ! records are ( ! scantie/ description4 ,= "s h\rs ! gr\nd )9 ! meizoseismal area is said to h trembl$ almo/ incessantly4 ,at ,pot5za _m slight %ocks1 bo? v]tical & horizontal1 7 felt dur+ ! night1 & = a mon? or m !y 7 s frequ5t z to r5d] enum]ation difficult4 ,mallet's la/ record is dat$ ,m>* #bcrd1 #aheh1 :5 f\r slight %ocks 7 felt at ,la ,sala & ,pot5za1 b occasional tremors 7 report$ to him until ,may #ahei4 ,! mo/ important ( all ^! aft]-%ocks 0 "o felt ab\t an h\r aft] ! pr9cipal e>?quake4 ,ev]y:]e f> less p[]ful1 x 0 yet /rong en\gh to %ake d[n _m build+s at ,polla t _h be5 %att]$ by ! great %ock4 ,t[>ds ! s\? at ,molit]no1 & t[>ds ! nor? at ,oliveto & ,b>ielle1 x evid5tly attract$ v little att5tion4 ,s f> z c be judg$ f ! evid5ce giv5 by ,mallet1 ! di/urb$ area seems to h be5 approximately ( ! same =m & dim5sions z ! meizoseismal area1 & elongat$ 9 ! same direction1 b conc5tric ) ! nor?-we/ focus4 ,on ! o!r h&1 if we may rely on too brief evid5ce1 sev]al aft]-%ocks record$ only at ,montemurro1 ,sapon>a1 ,viggiano1 or ,lagonegro1 7 probably connect$ ) ! s\?-ea/ or ,montemurro focus4 ,,orig9 ,,( ,,! ,,e>?quake4 ,mallet's !ories h suff]$ p]haps m ?an any o!r "p ( 8 "w f ! rec5t gr[? ( our k4 ,f a hi/orical po9t ( view1 "s ref]5ce to 8 explanation ( ! orig9 ( ! ,neapolitan e>?quake seems desirable1 & 8 own consci5ti\s "w dem&s x4 ,on ! o!r h&1 8 conclusions are1 = ! pres5t at any rate1 sup]s$$1 & x w !re=e be suffici5t to describe !m briefly4 ,mo/ ( ! wave-pa?s1 z we h se51 pass )9 ?ree miles ( a po9t almo/ co9cid5t ) ! village ( ,caggiano4 ,( ! rema9d]1 six trav]se a spot ab\t two miles f>!r to ! s\?-we/1 & ?ree cross ano!r ab\t two miles f>!r to ! nor?-ea/4 ,neglect+ o!r po9ts ( int]section1 b tak+ acc\nt ( ! obs]v$ em]g5ces at ,vietri di ,pot5za1 ,auletta1 ,polla1 etc41 ,mallet inf]s t ! horizontal section ( ! focus 0 a curve 7indicat$ by ! dott$ l9e 9 ,fig4 #i7 n less ?an t5 miles 9 l5g?1 & pass+ f ne> ,balvano on ! nor?1 close to ,vietri di ,pot5za1 ,caggiano1 & ,p]tosa1 to a po9t ab\t two & a half miles we/ ( ,polla4 ,aga91 he rem>ks1 ! obs]v$ em]g5ces at places ne> ! epic5tre indicate t ! v]tical section ( ! seismic focus 0 ei!r m or less curv$1 or m probably a surface incl9$ t[>ds ! s\?-ea/4 ,he concludes1 !re=e1 t ! seismic focus 0 a curv$ fissure1 #aj miles long & #c-a_/b miles 9 height1 & ) its c5tre at a dep? ( #f-a_/b miles bel[ ! level ( ! sea4 ,! production ( ?is great fissure1 accompani$1 p]haps by ! injection into x ( /eam at high pressure1 0 reg>d$ by ,mallet z ! cause ( ! pr9cipal e>?quake4 ,he imag9es t ! r5t w\ld />t at or ne> ! c5tral po9t ( ! focus & !n ext5d rapidly outw>ds 9 all directions4 ,9 ! initial /age1 vibrations ( v small amplitude w\ld alone be transmitt$1 & ^! w\ld give rise to ! e>ly s\nds & tremors4 ,z ! r5d+ proce$$1 ! vibrations w\ld increase 9 /r5g? up to a c]ta9 po9t :5 !y produc$ ! %ock itself4 ,aft] ?is1 !y w\ld decrease2 &1 9 ! f9al /age1 w\ld give place to ! small vibrations correspond+ to ! s\nds & tremors t m>k$ ! close ( ! e>?quake4 ,! ru% ( /eam at high pressure into ! focus ,mallet does n seem to h consid]$ ess5tial1 ?\gh he evid5tly reg>d$ x z possible1 inde$ probable2 & he sugge/s t x may h be5 9 "p ! cause ( ! e>?quake :i* occurr$ an h\r lat]4 ,?\gh feel+ sceptical z to ! exi/5ce ( any g5]al law ( increase ( und]gr\nd temp]ature1 he assumes x1 = ! sake ( illu/ration1 to be #a ,f4 = e #fj feet ( desc5t4 ,?is w\ld give a temp]ature ( #cci ,f4 at ! upp] limit ( ! focus1 #fdc ,f4 at its c5tral po9t1 & #hhd ,f4 at its l[] m>g94 ,if ! focus 7 fill$ ) /eam at ea* ( ^! temp]atures1 ! correspond+ pressures on its walls w\ld be #h1 #adi1 & #fhd atmosph]es1 respectively4 ,z ! /eam may be suppos$ to be admitt$ sudd5ly & to be unlimit$ 9 supply1 ,mallet inf]s t x might exi/ at ! t5sion due to ! highe/ ( ^! temp]atures1 9 :i* case x w\ld be capable ( lift+ a column ( lime/one #h1eej feet 9 height 7or ab\t "o-half ! dep? ( ! upp] m>g9 ( ! focus71 & w\ld ex]t a pressure on ! walls ( ! focus ( #d4eh tons p] squ>e in*1 or ( m ?an #fdj1ebh millions ( tons ^u its :ole surface4 ,s _m pages h already be5 giv5 to ?is int]e/+ e>?quake t ,i mu/ sket* /ill m briefly my own view z to its orig94 ,!re 71 ,i believe1 two di/9ct foci ) _! c5tres ab\t tw5ty-f\r miles ap>t along a nor?-we/ & s\?-ea/ l9e1 & x 0 to ?is arrangem5t t ! elongation ( ! meizoseismal area 0 *iefly1 ?\gh n entirely1 due4 ,! evid5ce is insuffici5t to det]m9e :e!r ! e>?quake 0 caus$ by fault-slipp+2 x is 9 no way oppos$ to ?is view1 b if ! ,neapolitan e>?quake /ood alone1 we %\ld h>dly be ju/ifi$ 9 draw+ any fur!r inf]5ce4 ,rely+1 h[ev]1 on k obta9$ f ! /udy ( m rec5t %ocks1 x seems to me probable t ! two foci =m$ p>ts ( "o fault ) a g5]al nor?-we/ & s\?-ea/ direction4 ,! slip caus+ ! fir/ "p ( ! d\ble %ock app>5tly took place )9 ! s\?-ea/ focus1 & 0 foll[$ aft] a few seconds by "o )9 ! nor?-we/ focus1 great] 9 am\nt z well z m deeply seat$4 ,9 consequ5ce ( ^! displacem5ts !re 7 local increases ( /ress1 caus+ num]\s small slips )9 or ne> bo? pr9cipal foci2 &1 if we may judge f "s slight %ocks felt at ,la ,sala1 accompani$ also by o!r m9or slips 9 ! int]m$iate region ( ! fault4 ,,ref]5ce4 ,,mallet1 ,r4--,! ,great ,neapolitan ,e>?quake ( #aheg3 ,! ,fir/ ,pr9ciples ( ,obs]vational ,seismology1 etc4 #b vols #ahfb4 ,,footnotes3 #c ,iri% ,acad4 ,trans41 vol4 xxi41 #ahdh1 pp4 #ea-aje 7read ,feb4 #i1 #ahdf74 #d ,brit4 ,assoc4 ,reports1 #ahej1 pp4 #a-hg2 #ahea1 pp4 #bgb-ccj2 #aheb1 pp4 #a-agf2 #ahec1 pp4 #aag-bab2 #ahed1 pp4 #a-cbf2 #aheh1 pp4 #a-acf4 #e ,a ,manual ( ,sci5tific ,enquiry1 edit$ by ,sir ,j4,f4,w4 ,h]s*el1 #ahdi1 pp4 #aif-bbc4 #f ,iri% ,acad4 ,trans41 vol4 xxii41 #ahee1 pp4 #cig-daj4 #g ,! l9e> dim5sions ( ! isoseismal l9es are obta9$ by measurem5ts f ,mallet's maps4 ,! areas are giv5 by him 9 geographical squ>e miles4 #h ,mallet1 by "s accid5t1 omitt$ ! losses at ,polla & neighb\r+ t[ns f ?is e/imate4 ,m]calli 7,geologia d',italia1 pte4 #c1 p4 #cbd7 gives ! numb] ( kill$ z m ?an #ab1cjj4 #i ,mallet does n make use ( ! t]m epic5tre2 he speaks ( ! l9e ,,fe z ! seismic v]tical4 ,! mod]n & accept$ t]ms are us$ above #aj ,japan ,seismol4 ,soc4 ,trans41 vol4 xi41 #ahhg1 pp4 #age-agg4 #aa ,ital4 ,seismol4 ,soc4 ,boll41 vol4 ii41 #ahif1 pp4 #ahj-ahh4 #ab ,pr(essor ,omori gives ! mean direction z ,s4 #ga ,w41 b ?is 0 obta9$ f obs]vation on lamps ) squ>e1 z well z ) circul> bases4 #ac ,twelve measurem5ts *os5 at r&om f ,pr(essor ,omori's li/ gave a mean direction ( ,s4 #gh ,w4 #ad ,:5 ! accuracy ( all ! obs]vations seem$ equally probable1 he adopt$ ! mean ( ! two extremes z ! true direction4 #ae ,if a be ! amplitude ( a simple h>monic vibration1 ,t its complete p]iod1 v its maximum velocity1 & f its maximum accel]ation1 we h v#b99pi99a_/,t & f#d99pi#b99;a_/,t#b #af ,e>?quakes & o!r ,e>? ,movem5ts1 pp4 #ha-hb4 #ag ,obta9$ f ! =mula3 ,t#b99pi99a_/v#b99pi99x997#a_/c7_/ab #ah ,if we take ! maximum velocity to be #ab feet p] second1 & ! p]iod to be "o second1 ! amplitude w\ld be ab\t #aa-a_/b in*es4 #ai ,vol4 ii41 p4 #bii4 ,! punctuation ( ! orig9al is n foll[$ 9 ! above extract4 #bj ,briti% ,association ,report1 #ahea1 pp4 #bgb-cbj4 ,,*apt] ,,iii4 ,,! ,,is*ian ,,e>?quakes ,,( ,,m>* #d,,?1 #ahha1 ,,& ,,july #bh,,?1 #ahhc4 ,sep>at$ f ,italy by a di/ance ( n m ?an six miles1 ,is*ia & ! int]m$iate isl& ( ,procida /rictly =m "p ( ! ,phlegran ,fields1 ! well-kn[n volcanic di/rict to ! nor? ( ,naples4 ,is*ia1 ! l>g] ( ! two isl&s1 is six miles long f ea/ to we/1 & five miles f nor? to s\?1 & conta9s an area ( tw5ty-six squ>e miles4 ,9 #ahha1 ! total population 0 #bb1agj1 t ( ,casamicciola1 ! l>ge/ t[n1 be+ #c1ifc4 ,,volcanic ,,hi/ory ,,( ,,is*ia4 ,! c5tral feature ( ,is*ia is ! great crat] ( ,epomeo 7a1 ,fig4 #ad74 ,on ! s\? side1 & p>tly also on ! ea/1 ! crat]-wall has be5 brok5 d[n & remov$2 ! portion rema9+ is ab\t #a-a_/b mile 9 diamet] f ea/ to we/1 & rea*es a height ( #b1fjj feet above ! sea-level4 ,all ! upp] "p ( ! m\nta9 is compos$ ( a pumice\s tufa1 ri* 9 sanid9e & ( a *>act]i/ic gre5i% col\r4 ,at two po9ts1 to ! we/ ne> ,=io & to ! nor? betwe5 ,lacco & ,casamicciola1 ?is tufa is se5 rea*+ d[n to ! sea2 b1 9 all o!r p>ts1 x is cov]$ by /reams ( tra*itic lava1 by m rec5t tufas1 or by a deposit ( m>ly appe>ance1 :i* is reg>d$ by ,fu*s z result+ f ! decomposition ( ! ,epomean tufa4 ,!re are two di/9ct p]iods 9 ! geological hi/ory ( ,is*ia4 ,! fir/1 a subm>9e p]iod1 probably began ) ! dawn ( ! quat]n>y epo*1 = all ! m>9e fossils ( ! isl& belong to exi/+ species4 ,ab\t ?is "t1 ,epomeo seems to h orig9at$ 9 eruptions occurr+ 9 a sea at lea/ #a1gjj feet 9 dep?--eruptions t prec$$ ! =mation ( ,monte ,somma & 7 ei!r contemporane\s or alt]nat+ ) ^? t gave rise to ! olde/ tra*itic tufas ( ! ,phlegran ,fields4 ,! de/ruction ( ! s\? wall may h occurr$ mu* lat] ?r\gh "s great eruptive p>oxysm1 b m probably1 z ,pr(essor ,m]calli sugge/s1 ?r\gh e>ly m>9e erosion & subsequ5t suba]ial d5udation4 ,to ! subm>9e p]iod mu/ also be assign$ ! =mation ( ! tra*itic masses :i* compose ,monti ,trippiti1 ,vetta1 & ,g>(oli 7b1 c1 d1 ,fig4 #ad71 on ! ea/ side ( ,epomeo2 &1 9 "p only1 ^? ( ,monte ,campagnano & ,monte ,vezza 7f1 g74 ,at or ne> ! close ( ! elevation1 _m viol5t eruptions occurr$ on ! s\?-we/ ( ,epomeo1 dur+ :i* 0 =m$ ! s\?-we/ corn] ( ! isl&1 includ+ ,monte ,imp]atore & ,capo ,sant' ,angelo 7h1 i74 ,9 ! second or t]re/rial p]iod1 :5 ! isl& _h practically atta9$ its pres5t altitude1 ! eruptive activity 0 almo/ conf9$ to ! ea/]n & nor!rn flanks ( ,epomeo4 ,at ! beg9n+ ,monte ,lo ,toppo 7j7 0 =m$ by a lat]al eruption4 ,9 ! nor?-we/ corn] ( ! isl&1 ,monte ,m>ecocco & ,monte ,zale 7k & l7 owe _! orig9 to a gigantic fl[ ( sanid9ic tra*ite1 issu+ probably f ! depression :i* n[ exi/s betwe5 !m4 ,la/ly1 t[>ds ! nor?-ea/1 are ! rec5t lat]al crat]s ( ,rot>o1 ,montagnone1 ,bagno1 & ,cremate 7m1 n1 p1 s71 ! fir/ two be+ ! mo/ regul> & be/ pres]v$ 9 ! isl&4 ,illu/ration3 ,,fig4 #ad4--;,geological sket*-map ( ,is*ia4 7,m]calli47#ba ,! e>lie/ eruption ( ! hi/oric1 or r human1 p]iod appe>s to h tak5 place f ,montagnone1 & probably also at ab\t ! same "t f ! second>y crat] ( ,porto d',is*ia 7u71 ab\t ! beg9n+ ( ! elev5? c5tury ,b4,c4 ,! eruptions ( ,m>ecocco & ,zale are ref]r$ to ab\t ,b4,c4 #dgj2 & ^? ( ,rot>o & ,tabor 7q7 to betwe5 ! ye>s #djj & #ceb ,b4,c4 ,ano!r eruption is said to h occurr$ 9 ,b4,c4 #hi1 b ! site ( x is unkn[n2 & ?ree o!rs are record$ on d\btful au?ority ab\t ! ye>s ,a4,d4 #gi-ha1 #ach-afa1 & #bhd-cje4 ,! la/ outbur/ ( all took place aft] ! s]ies ( e>?quakes 9 #acjb f a new crat]1 t ( ,cremate 7s71 :i* op5$ on ! nor?-ea/ flank ( ,epomeo1 & f :i* a /ream ( lava1 call$ ! ,arso 7t71 fl[$ d[n rapidly &1 aft] a c\rse ( two miles1 rea*$ ! sea4 ,aft] ! fir/ eruptions to :i* x ow$ its orig91 ! c5tral crat] ( ,epomeo app>5tly rema9$ inactive4 ,all ! lat] eruptions occurr$ ei!r on ! ext]nal flanks ( ! m\nta9 or on radial fractures ( ! cone4#bb ,trippiti1 ,lo ,toppo1 ,montagnone & ! ,lago del ,bagno 7b1 j1 n1 p7 lie 9 "o l9e1 ,vetta & ,cremate 7c1 s7 on ano!r1 & ,g>(oli & ,vatoli]e 7d1 e7 on a ?ird1 all pass+ ?r\gh a po9t ne> ! t[n ( ,fontana1 :i* occupies ! c5tre ( ! old crat] ( ,epomeo4 ,pr(essor ,m]calli po9ts out t ! lat]al eruptions ( ,epomeo diff] 9 "o respect f ^? ( ,etna & ,vesuvius4 ,9 ^! volcanoes ! lava asc5ds to a consid]able height 9 ! c5tral *imney1 & by its own weight r5ds op5 ! flanks ( ! cone4 ,9 ,epomeo1 x appe>s to trav]se lat]al passages at "s dep?1 p]haps f> bel[ ! level ( ! sea1 & to r5d ! m\nta9 by means ( ! ela/ic =ce ( ! aque\s vap\r1 etc41 :i* x conta9s4 ,x w be se5 h[ important is ! be>+ ( ?is diff]5ce on ! occurr5ce ( ! ,is*ian e>?quakes4 ,! eruptions t h tak5 place dur+ ! la/ ?ree ?\s& ye>s agree 9 sev]al p>ticul>s4 ,!y ei!r occurr$ sudd5ly1 or1 at any rate1 7 n prec$$ by a /age ( mod]ate ,/rombolian activity2 !y 7 always accompani$ by viol5t e>?quakes2 & all succe$$ int]vals ( long repose4 ,z ! eruption ( #acjb happ5$ aft] at lea/ a ?\s& ye>s ( re/1 ! lapse ( six m c5turies does n ju/ify u 9 conclud+ t ,epomeo is at la/ ext9ct4 ,we seem1 on ! contr>y1 to be draw+ ne> ano!r epo* ( activity4 ,dur+ ! f\r & a half c5turies t foll[$ ! eruption ( #acjb1 we h no record ( ,is*ian e>?quakes4#bc ,!n1 sudd5ly1 on ! night ( ,july #bh-bi1 #agfb1 ,casamicciola 0 visit$ by sixty-two %ocks1 "s ( :i* 7 v /rong & damag$ build+s4 ,on ,m>* #ah?1 #agif1 ano!r sev]e %ock took place1 b de/ructive only 9 ! neighb\rhood ( ,casamicciola1 :]e sev5 p]sons 7 kill$4 ,on ,febru>y #bnd1 #ahbh1 ! area ( damage1 ?\gh conc5tric ) ! =m]1 enl>g$ its b\nd>ies2 #cj p]sons 7 kill$ & #ej w\nd$4 ,on ,m>* #f?1 #ahda1 & dur+ ! night ( ,augu/ #ae-af1 #ahfg1 fur!r %ocks injur$ h\ses at ,casamicciola1 b )\t caus+ any loss ( life4 ,slight tremors occurr$ at v>i\s dates 9 #ahgd1 #ahge1 #ahgi1 & #ahhj1 lead+ up to ! disa/r\s e>?quakes "h describ$1 ^? ( ,m>* #d?1 #ahha1 :5 #abg p]sons 7 kill$1 & ,july #bh?1 #ahhc1 :i* result$ 9 ! dea? ( #b1cac p]sons & ! w\nd+ ( _m o!rs4 ,,e>?quake ,,( ,,m>* #d,,?1 #ahha4 ,! ,is*ian e>?quakes h be5 =tunate 9 _! inve/igators4 ,9 ! spr+ ( #ahha1 ,dr4 ,h4,j4 ,john/on-,lavis1 ! *ronicl] = _m ye>s ( ,vesuvian ph5om5a1 0 resid+ 9 ,naples4 ,impress$ by a rec5t p]usal ( ,mallet's report on ! ,neapolitan e>?quake1 & wi%+ to te/ ! value ( ! me?ods expla9$ 9 ! la/ *apt]1 he cross$ ov] to ,is*ia on ,m>* #e?2 & to 8 unwe>i$ inquiries ext5d+ ov] m ?an ?ree weeks & la/+ f ?irte5 to sixte5 h\rs a day1 we are indebt$ = mo/ ( :at we "k ab\t ! e>?quake ( #ahha4 ,on ,m>* #d?1 at #a4e ,p4,m41 ! great %ock occurr$ abruptly1 )\t any w>n+ tremors4 ,its effects 7 aggravat$ by ! faulty con/ruction ( ! h\ses4 ,! walls are ( great ?ickness1 loosely put toge!r1 & connect$ by mort> ( ! poore/ quality4 ,! *imneys & ro(s also are massive1 & ! raft]s are s slightly ins]t$ 9 ! walls t !y 7 drawn out ) ! rock+ ( ! h\ses4 ,9 su* cases1 ! de/ruction 0 (t5 s complete t no fissures 7 left available = measurem5t4 ,,isoseismal ,,l9es ,,& ,,di/urb$ ,,area4 ,! isoseismal l9es z drawn by ,dr4 ,john/on-,lavis are repres5t$ by ! curves 9 ,fig4 #ae4 ,! isoseismal m>k$ #a b\nds ! area ( complete de/ruction2 x is ab\t #a mile long f ea/ to we/1 #b_/c ( a mile broad1 & conta9s an area ( n m ?an half a squ>e mile4 ,! next isoseismal 7#b7 m>ks ! area ( p>tial1 b /ill s]i\s1 de/ruction2 ?is is ne>ly #b miles long f ea/ to we/1 #a-a_/d miles broad1 & #b squ>e miles 9 area4 ,)9 ! isoseismal #c1 build+s 7 m or less slightly damag$4 ,! c\rse ( ?is curve is some:at d\btful1 b1 z drawn1 x is ab\t #c miles long1 #b miles wide1 & #e squ>e miles 9 area4 ,illu/ration3 ,,fig4 #ae4--;,isoseismal l9es ( ! ,is*ian e>?quake ( #ahha4 7,john/on-,lavis47 ,outside ! la/ curve1 ! %ock dim9i%$ rapidly 9 int5sity4 ,at ,monte ,tabor & ,bagno1 x 0 v slight2 9 ! t[n ( ,is*ia1 only ab\t half ! p 7 consci\s ( any movem5t2 & at ,capella1 a small village to ! s\?1 x 0 n felt at all4 ,aga91 ! %ock 0 p]ceptible1 ?\gh only fa9tly1 9 ! neighb\rhood ( ,campagnano1 at ,s]r>a to ! s\? ( ,epomeo1 & at ,panza ne> ! s\?-we/ corn] ( ! isl&4 ,on ! o!r h&1 at ,fontana1 :i* occupies approximately ! c5tre ( ! crat] ( ,epomeo1 !re 7 evid5ces ( a di/9ctly /rong] %ock4 ,no h\se actually fell1 & side walls 7 b little injur$2 b ! ro(s1 :i* are ( great weight1 suff]$ consid]able injury4 ,9 ! adjac5t isl& ( ,procida1 ! %ock 0 felt di/9ctly by _m p1 & by "s1 ?\gh slightly1 at ,monte di ,procida1 ,mis5um1 & ,bacoli1 on ! coa/ ( ,italy4 ,no record :atev] 0 giv5 by ! seismographs 9 ! univ]sity ( ,naples & ! obs]vatory on ,vesuvius4 ,we h ( c\rse no means ( e/imat+ ! exact size ( ! di/urb$ area1 b 9 ?is respect1 disa/r\s z ! e>?quake 0 9 ! neighb\rhood ( ,casamicciola1 x 0 cle>ly inf]ior to all b ! v weake/ e>?quakes felt 9 ! ,briti% ,isl&s4 ,,position ,,( ,,! ,,epic5tre4 ,9 det]m9+ ! position ( ! epic5tre1 ,mallet's me?od 0 closely foll[$4 ,fissures 9 build+s 7 us$ = ! mo/ "p1 9 two out ( e ?ree cases2 & occasional measurem5ts 7 made f objects ov]?r[n1 project$1 or %ift$1 & also f ! p]sonal exp]i5ces ( obs]v]s4 ,! attempt to apply ! me?od 01 h[ev]1 fraught ) difficulties4 ,! het]og5e\s /ructure ( ! isl& 0 no d\bt responsible = _m div]g5t azimu?s2 ! irregul>ity ( ! build+s bo? 9 =m & mat]ial & _! v>iety ( site furni%$ o!r s\rces ( error2 ev5 ! smallness ( ! area 0 a disadvantage 9 less5+ ! numb] ( tru/wor?y records4 ,measurem5ts 7 made at #ee places altoge!r1 b 9 mo/ cases !y 7 ! results ( isolat$ obs]vations1 n ! means ( sev]al at ea* place4 ,on ?is acc\nt1 ,i h n reproduc$ 9 ,fig4 #ae ! azimu?s %[n 9 ,dr4 ,john/on-,lavis's map ( ! e>?quake4 ,a l>ge numb] ( !m cle>ly conv]ge t[>ds an area ly+ to ! we/ ( ,casamicciola2 &1 f _! arrangem5t1 ,dr4 ,john/on-,lavis concludes1 ?\gh ! evid5ce does n seem to me q /rong en\gh = ! purpose1 t !y emanat$ f a fracture runn+ f a little we/ ( nor? to a little ea/ ( s\?4 ,?is conclusion is1 h[ev]1 ju/ifi$ by o!r evid5ce4 ,9 ! c5tre ( ! injur$ di/rict1 ,dr4 ,john/on-,lavis has trac$ a meizoseismal b&1 9 :i* ! %ock mu/ h be5 ne>ly or q v]tical4 ,! damage inflict$ on build+s includ$ )9 ?is b& 01 he says1 v *>act]i/ic ( ! nature ( ! %ock2 ! walls hav+ receiv$ b slight injury1 :il/ almo/ e floor & ceil+ _h be5 totally de/roy$4 ,9 fact1 he adds1 _m h\ses w\ld h requir$ no o!r repairs ?an ! replac+ ( ! divisions betwe5 ! diff]5t /oreys4 ,! %ad$ c5tral area 9 ,fig4 #ae repres5ts ?is b&1 pass+ 9 a ne>ly nor? & s\? direction f a po9t midway betwe5 ,campo & ! upp] "p ( ,lacco on ! nor?1 ?r\gh ! we/ "p ( ,casam5ella & ,campo1 to a po9t ne> ,frasso on ! s\?2 ! l5g? ( ! b& be+ ?us ab\t two-?irds ( a mile4 ,if ! c5tral l9e ( ?is b& is produc$ t[>ds ! s\?1 z indicat$ by ! dott$ l9e1 x grazes ! we/ side ( ,fontana1 :]e1 z we h se51 !re 0 a second meizoseismal area1 mu* small] ?an ! o!r & surr\nd$ by a di/rict 9 :i* h\ses 7 almo/ un9jur$4 ,t ! %ock 9 ?is t[n 0 v]tical or ne>ly s1 is %[n by ! nature ( ! damage 7p4 #eb7 & also by ! te/imony ( ! inhabitants4 ,i w give ,dr4 ,john/on-,lavis's explanation ( ?is deta*$ meizoseismal area :5 discuss+ ! orig9 ( ! ,is*ian e>?quakes2 b ! evid5ce seems to me to fav\r ei!r ! exi/5ce ( two di/9ct foci or1 m probably p]haps1 ! ext5sion ( ! fissure to ! s\? ) an increas$ impulse b5ea? ! c5tre ( ,epomeo4 ,,dep? ,,( ,,! ,,seismic ,,focus4 ,at n9e places1 ,dr4 ,john/on-,lavis 0 able to make measurem5ts ( ! angle ( em]g5ce1 9 e case f fissures 9 build+s1 & !re=e liable to s\rces ( error already ref]r$ to4 ,on ! o!r h&1 ow+ to ! small dep? ( ! focus1 !re w\ld probably be less g5]al refraction ( ! wave-pa?s ?an 9 ! ,neapolitan e>?quake4 ,! dep?s indicat$ by ^! obs]vations v>y betwe5 ab\t #fae & #b1hhe feet1 a diff]5ce t is no great] ?an might be expect$1 z ! size ( ! focus 0 no d\bt comp>able ) t ( ! di/rict 9 :i* obs]vations 7 made4 ,! mean dep? ,dr4 ,john/on-,lavis f9ds to be ab\t #a1gjj feet1 or a little less ?an "o-?ird ( a mile4 ,,nature ,,( ,,! ,,%ock4 ,! limit$ dep? ( ! focus is also evid5t f ! nature ( ! %ock4 ,x 0 only )9 ! actual meizoseismal b& t ! %ock 0 subsultory or v]tical ?r\gh\t2 at a %ort di/ance f ! epic5tre1 ! movem5t 0 bo? subsultory & undulatory2 :ile ne> ! ?ird isoseismal1 & 9 mo/ ( ! region outside1 ! movem5t 0 entirely undulatory or lat]al4 ,an obs]v] at ,p]rone 7:i* lies #a-b_/c miles ea/ ( ! epic5tre7 gives ! foll[+ acc\nt ( ! %ock3--,i 0 /&+ on my balcony 7?is faces ,casamicciola7 admir+ ! sc5e 444 :5 ,i felt ! h\se rock1 feel+ at ! same "t z if some?+ 0 roll+ along b5ea? ! gr\nd4 ,?is movem5t 0 accompani$ by a s\nd l ?is1 ,boob1 boob -- boob -- -- boob -- -- -- boob -- -- -- -- boob4 ,bo? noise & movem5t seem$ to come f ,casamicciola4444 ,9 a few seconds1 9 ! di/ance ov] ! t[n arose a t]rific cl\d ( :ite du/1 s t ,i imag9$ ! t[n on fire4444 ,i felt h>dly any1 if any1 subsultory movem5t1 b z ,i leant ^u ! balcony rails1 ,i 0 alt]nately press$ aga9/ !m & !n drawn away4 ,at ,fontana1 h[ev]1 ! undulatory %ock 0 replac$ by a v]tical "o4 ,?is 0 ! univ]sal exp]i5ce1 ?\gh "o or two p]sons felt a slight lat]al movem5t imm$iately aft]4 ,at ,valle 7ne> ,b>ano7 & ,piejo1 bo? places ab\t a mile f ,fontana1 ! v]tical compon5t 0 also p]ceptible4 ,,aft]-,,%ocks4 ,! aft]-%ocks 7 few & ( slight int5sity4 ,dr4 ,john/on-,lavis gives ! foll[+ dates3 ,m>* #g?1 #ab4e ,a4,m4 & midday2 ,m>* #aa-ab1 #ae-af1 #ag-ah1 #bg 7871 ,april #e? & #f?1 & ,july #ah?1 #h4cj ,p4,m4 ,! only %ock ( ! s]ies m>k$ z /rong occurr$ at midnight on ,m>* #ae-af at ,casamicciola4 ,! la/ ( all1 t ( ,july #ah?1 consi/$ ( a rumble & slight %ock1 & 0 mo/ p]ceptible at ,fango4 ,,e>?quake ,,( ,,july #bh,,?1 #ahhc4 ,undet]r$ by ! exp]i5ce ( #ahha or by ! w>n+s ( seismologi/s1 ,casamicciola 0 rebuilt1 only to suff] m complete disa/]4 ,on ,july #bh?1 #ahhc1 at #i4be ,p4,m41 occurr$ ! mo/ de/ructive e>?quake ( :i* we h any record 9 ,is*ia4 ,! %ock la/$ ab\t fifte5 seconds1 & be=e x 0 ov] cl\ds ( du/ 7 ris+ above ! ru9s ( ,casamicciola1 ,lacco1 & ,=io2 #a1bjj h\ses 7 de/roy$1 #b1cac p]sons 7 kill$1 ne>ly #a1hjj 9 ,casamicciola alone1 & m ?an #hjj s]i\sly w\nd$4 ,no bett] idea1 says ,dr4 ,john/on-,lavis1 ( ! absolute de/ruction ( build+s c\ld be conceiv$ ?an :at 0 actually realis$ at ,casamicciola & ,campo4 ,look+1 on ! foll[+ ,monday1 ov] ! field ( de/ruction1 ,i c\ld discov] 7) few exceptions7 ! wall-/umps only rema9+4 ,dr4 ,john/on-,lavis aga9 sp5t ab\t ?ree weeks 9 ! isl&1 exam9+ ! effects ( ! new %ock ) equal zeal & wid] exp]i5ce4 ,8 monograph is n[ our *ief "w ( ref]5ce on ,is*ian e>?quakes4 ,inquiries 7 also made by sev]al ,italian seismologi/s1 among o!rs by ,pr(essor ,m4,s4 de ,rossi1 ! organis] ( e>?quake-/udies 9 ! p59sula2 by ,pr(essor ,l4 ,palmi]i1 ! f\nd] ( ! ,vesuvian obs]vatory2 & especially by ,pr(essor ,g4 ,m]calli1 ^: valuable memoir supplem5ts ! report ( ,dr4 ,john/on-,lavis 9 "s important p>ticul>s4 ,,prep>atory ,,signs4 ,! int]val betwe5 ,july #ah?1 #ahha1 :5 ! la/ %ock ( t ye> 0 felt1 & ,july #bh?1 #ahhc1 0 "o ( almo/ complete quiesc5ce4 ,e>ly 9 ,m>* #ahhb1 a few slight %ocks 7 notic$ at ,casamicciola4 ,on ,july #bd?1 #ahhc1 a wat* hang+ f a nail 9 a wall 0 se5 to sw+ at #f ,a4,m4 & #i ,a4,m41 &1 on ! same morn+1 at ab\t #h4cj1 a slight %ock1 accompani$ by a rumbl+ s\nd1 0 felt at ,casamicciola4 ,aga91 on ! #bh?1 ab\t a qu>t] ( an h\r be=e ! great %ock1 "o obs]v] at ,casamicciola /ates t an und]gr\nd noise 0 he>d1 & t "s p]sons 9 consequ5ce left _! h\ses4 ,_m ass]tions h be5 made ) reg>d to v>iations witness$ a day or two be=e ! %ock 9 ! hot spr+s1 su* z an increase ( fl[ or temp]ature & *anges 9 _! volume & purity4 ,fum>oles are alleg$ to h bur/ out ) viol5ce1 & ev5 flames to h be5 se54 ,! /atem5ts1 ?\gh widely quot$1 c h>dly be said to re/ on satisfactory evid5ce4 ,on ! o!r h&1 ,dr4 ,john/on-,lavis arriv$ 9 ! isl& )9 tw5ty-f\r h\rs aft] ! %ock1 &1 be=e ano!r day _h elaps$1 he _h exam9$ mo/ ( ! places :]e ! ph5om5a 7 said to h occurr$1 b c\ld f9d no rem>kable *ange nor any signs ( su* hav+ tak5 place4 ,x is also kn[n1 z he rem>ks1 t ! temp]ature ( ! ,is*ian spr+s & fum>oles sometimes v>ies consid]ably )\t any e>?quake foll[+1 t ( ! wat] ( ,gurgitello occasionally *ang+ by z mu* z #cj or #dj4 ,we may !re=e1 ,i ?9k1 conclude t1 except = "o or two %ocks & und]gr\nd noises too slight to cause g5]al al>m1 !re 7 no decisive h]alds ( ! great e>?quake4 ,,isoseismal ,,l9es ,,& ,,di/urb$ ,,area4 ,! curves 9 ,fig4 #af repres5t ! isoseismal l9es z drawn by ,dr4 ,john/on-,lavis4 ,z 9 ! e>?quake ( #ahha1 !y b\nd respectively ! areas ( complete de/ruction1 p>tial de/ruction & slight damage to build+s1 ! c\rse ( ! out] l9e be+ to a great ext5t conjectural ow+ to ! small ext5t ( l& trav]s$ by x4 ,! fir/ isoseismal is ab\t #b-a_/b miles long1 #a-a_/b miles broad1 & #c squ>e miles 9 area2 ! second ab\t #d miles long1 #c-a_/b miles broad1 & #aa squ>e miles 9 area2 & ! ?ird ab\t #f-a_/b miles long1 #f miles broad1 & #cj squ>e miles 9 area4 ,! curve drawn by ,pr(essor ,m]calli 7,fig4 #ad7 co9cides ne>ly ) ! second ( ^! l9es4 ,at ,fontana1 ! damage exce$$ t 9 ! surr\nd+ c\ntry1 ?\gh ! diff]5ce 0 ( c\rse less m>k$ ?an on ! previ\s occasion4 ,illu/ration3 ,,fig4 #af4--;,isoseismal l9es ( ! ,is*ian e>?quake ( #ahhc4 ,outside ,is*ia1 ! %ock 0 felt di/9ctly 9 all ! isl& ( ,procida & 9 ,viv>a2 on ! ma9l&1 by "s z f> z ,pozzuoli & by sev]al p]sons 9 ,naples1 :i* is tw5ty miles f ,casamicciola4 ,! seismograph at ! univ]sity ( ?is city regi/]$ two small %ocks1 ! fir/ at #i4aj ,p4,m41 & ! second & /rong] at #i4be ,p4,m42 & ,de ,rossi /ates t at ab\t #i4cj ,p4,m4 ! seismographs at ,ceccano1 ,velletri1 & ,rome record$ a %ock consi/+ ( v sl[ undulations4 ,!re are aga9 no mat]ials = e/imat+ ! size ( ! di/urb$ area1 b !re c be no d\bt t x 0 mu* less ?an t ( a mod]ately /rong ,briti% e>?quake4 ,,position ,,( ,,! ,,epic5tre4 ,ow+ to ! limit$ size ( ! di/urb$ area1 "t-obs]vations1 ev5 _h !y be5 available1 w\ld n h suffic$ to det]m9e ! position ( ! epic5tre1 & bo? ,dr4 ,john/on-,lavis & ,pr(essor ,m]calli !re=e _h rec\rse to ,mallet's me?od1 ! =m] rely+ *iefly1 z be=e1 on fissures 9 damag$ build+s1 & ! latt] on ! ov]?r[ or displacem5t ( columns & o!r objects4 ,dr4 ,john/on-,lavis measur$ ! azimu? ( ! wave-pa?s at sixty-five places1 & at ab\t "o-?ird ( ^! 0 able to make two or m obs]vations4 ,! azimu?s conv]ge t[>ds ! same region z 9 #ahha1 b ! area cov]$ by _! int]sections is l>g]4 ,! meizoseismal b& ( maximum v]tical de/ruction indicat$ by %ad+ 9 ,fig4 #af is also ( ! same =m & slightly great] ext5t1 rea*+ f ! upp] "p ( ,lacco to a little s\? ( ,frasso1 & be+ !re=e ne>ly a mile 9 l5g?4 ,! c5tre ( maximum impulse 0 9 ! same position z 9 #ahha1 or possibly a little m to ! s\?4 ,pr(essor ,m]calli's obs]vations 7 made at =ty-eight places1 & 9 only six cases 7 !y ! same z ^? us$ by 8 pr$ecessor4 ,he also notices t mo/ ( ! azimu?s conv]ge t[>ds ,casam5ella1 & int]sect )9 an elongat$ area4 ,?is area runs 9 ! same direction z ,dr4 ,john/on-,lavis's meizoseismal b&1 b is less elongat$1 & situat$ a %ort di/ance f>!r to ! s\?1 ?\gh on ! :ole ! agreem5t betwe5 ! two areas is rem>kably close4 ,!re 0 aga9 app>5tly a second epic5tre at ,fontana4 ,9 ?is t[n1 accord+ to ,dr4 ,john/on-,lavis1 !re 7 two di/9ct types ( damage4 ,z 9 #ahha1 !re 0 evid5ce ( a v]tical bl[1 ! only "o t absolutely ru9$ h\ses2 b1 9 addition1 !re 0 ano!r indep5d5t set ( fissures1 q z widely di/ribut$ z ! o!rs1 ?\gh evid5tly caus$ by a less viol5t movem5t4 ,^! indicat$ a wave-pa? ) a l[ angle ( em]g5ce com+ f betwe5 nor? & nor?-nor?-we/1 or almo/ exactly 9 ! l9e ( meizoseismal b&4 ,to ! s\? ( ,fontana1 h[ev]1 !re is a gr\p ( places1 includ+ ,panza1 ,s]r>a1 ,b>ano1 etc41 :]e ! azimu?s div]g$ r widely f ! epic5tre at ,casam5ella4 ,^! azimu?s are twelve 9 numb]1 & x is wor?y ( notice t !y all int]sect$ ! crat] ( ,epomeo1 :ile half ( !m pass$ )9 a few hundr$ y>ds ( ,fontana4 ,,dep? ,,( ,,! ,,seismic ,,focus4 ,measurem5ts ( ! angle ( em]g5ce 7 made by ,dr4 ,john/on-,lavis at tw5ty-f\r places1 & 9 e case f fissur$ walls4 ,! great] "p ( ! diagram on :i* 8 results are depict$ is reproduc$ 9 ,fig4 #ag4 ,! horizontal l9e1 z 9 ,fig4 #ac1 repres5ts ! level ( ! sea1 ! long] v]tical l9e "o pass+ ?r\gh ! epic5tre1 & ! %ort] ano!r ?r\gh ,fontana4 ,! %ort l9es on ! left ( ! =m] %[ ! incipi5t wave-pa?s to places ly+ ea/ ( ! epic5tre2 ^? on ! "r1 ) "o exception1 repres5t ! wave-pa?s to places we/ ( ! same m]idian4 ,small horizontal m>ks are ins]t$ on ! v]tical l9es to %[ ! dep? 9 t5?s ( a mile bel[ ! level ( ! sea4 ,illu/ration3 ,,fig4 #ag4--;,diagram ( wave-pa?s at seismic v]tical ( ,is*ian e>?quake ( #ahhc4 7,john/on-,lavis47 ,! six angles ( em]g5ce t w\ld give ! greate/ dep? bel[ ! epic5tre 7 all measur$ at places 9 ! s\? ( ! isl& close to ! l9e jo9+ ,panza & ,b>ano1 & x w be notic$ t five ( ^! app>5t dep?s are mu* great] ?an ^? obta9$ f ! o!r wave-pa?s4 ,exclud+ ^! obs]vations1 ! rema9+ eighte5 give dep?s rang+ f ab\t #dej to ab\t #c1cej feet1 & a mean dep? ( #a1gcj feet1#bd or ne>ly "o-?ird ( a mile1 t is1 almo/ exactly ! same z ! mean dep? f\nd f ! e>?quake ( #ahha4 ,! six exceptional angles ( em]g5ce come f ! di/rict ( div]g5t azimu?s to ! s\? ( ,epomeo4 ,?ree ( ! correspond+ azimu?s pass )9 "o-qu>t] ( a mile f ! c5tre ( ,fontana1 & none ( ! o!r ?ree m ?an ?ree-qu>t]s ( a mile f ! same po9t4 ,?\gh disbeliev+ 9 a subsidi>y focus bel[ ?is t[n1 ,dr4 ,john/on-,lavis has calculat$ its mean dep?1 suppos+ x to exi/1 & f\nd x to be ab\t #a1efj feet bel[ ! sea level1 a result :i* is rem>kably close to ! calculat$ mean dep? ( ! focus ne> ,casam5ella4 ,,nature ,,( ,,! ,,%ock4 ,9 ! meizoseismal b&1 prelim9>y tremor & rumbl+ s\nd 7 alike abs5t4 ,s sudd51 inde$1 0 ! onset ( ! e>?quake1 t ! survivors g5]ally f\nd !mselves b5ea? ! ru9s ( _! h\ses be=e !y 7 consci\s ( any %ock4 ,! de/ruction1 practically in/antane\s1 0 wr\ght by f\r or five v]tical bl[s1 s p[]ful t1 accord+ to "s obs]v]s1 ,casamicciola seem$ to jump into ! air4 ,!n foll[$ undulations1 n notic$ by all1 t appe>$ to come f e direction4 ,! %ock la/$ altoge!r fifte5 seconds or m1#be & 0 accompani$ by a rumbl+ noise1 9 ! mid/ ( :i* 7 detonations z ( ?und] or ( great bl[s giv5 ^u an empty b>rel4 ,9 ! imm$iate neighb\rhood ( ! meizoseismal area1 at ,p]rone1 ,p5nella1 & ,l[] ,lacco1 ! subsultory movem5t 0 /ill ! m prom95t2 b1 f>!r away1 z at ,panza1 ,te/ac*io1 ,b>ano1 ,is*ia1 & ,bagno1 ! subsultory motion 0 foll[$ by di/9ctly horizontal undulations1 :ile outside ! isl& ( ,is*ia only sl[ undulatory movem5ts 7 p]ceptible4 ,,l&slips4 ,! dott$ areas 9 ,fig4 #af indicate ! sites ( ! only l&slips ( importance t 7 precipitat$ by ! e>?quake ( #ahhc4 ,two ( ^! occurr$ on ! nor? slope ( ,epomeo1 & ! ?ird on ! we/ flank ( ,monte ,rot>o4 ,! mat]ials ( ! ,epomean l&slips _h evid5tly be5 sep>at$ = "s "t by %all[ fissures f ! adjo9+ rock1 = ! surfaces ( ! fissures 7 discol\r$ by fum>olic action4 ,imm$iately aft] ! e>?quake a cl\d ( du/ 0 se5 to rise f ! spots2 ! masses1 already deta*$ lat]ally1 7 m]ely set 9 motion by ! %ock2 & !y cont9u$ to slide d[n dur+ ! foll[+ days ei!r ?r\gh ! action ( ! aft]-%ocks or ( ! heavy ra9s t foll[$4 ,all ov] ! isl&1 h[ev]1 fissures & m9or l&slips occurr$4 ,at two places on ! nor? coa/ ! /eep cliffs ( incoh]5t tufa 7 s mu* damag$ t1 accord+ to ,dr4 ,john/on-,lavis1 l>ge quantities ( _! mat]ials 7 ?r[n into ! sea4 ,! wat] !n sort$ out ! pieces ( pumice1 :i* 9 _m cases 7 ( v l>ge size1 & 7 se5 float+ ab\t 9 ! neighb\rhood = "s days1 giv+ rise to ! supposition t a subm>9e eruption _h tak5 place to ! nor? ( ! isl&4 ,,aft]-,,%ocks4 ,! aft]-%ocks 9 #ahhc 7 mu* m num]\s ?an 9 #ahha4 ,betwe5 #i4be ,p4,m4 on ,july #bh? & noon on ,augu/ #crd1 tw5ty-"o slight %ocks 7 record$ at ,casamicciola4 ,at #b4ae ,p4,m4 on ,augu/ #crd1 a viol5t %ock occurr$ t caus$ fur!r damage at ,=io1 & ev5 at places s f> f ! epic5tre z ,fiaiano1 ,b>ano1 & ,fontana1 & increas$ ! displacem5ts ( ! l&slips on ,epomeo4 ,?is %ock 0 also regi/]$ at ! obs]vatory on ,vesuvius4 ,aft] ?is ! %ocks became less frequ5t & slight]1 twelve be+ felt at ,casamicciola dur+ ! rema9d] ( ! ye>1 & six 9 ! fir/ half ( #ahhd4 ,sev]al %ocks & rumbl+ noises 7 also obs]v$ 9 o!r p>ts ( ! isl&4 ,among !m may be m5tion$ noises he>d at ,fontana on ,augu/ #ab? & #ae?1 & a slight %ock at ! same place on ,augu/ #ag?2 also on ,septemb] #d?1 at #aj4cj & #aj4dj ,a4,m41 slight %ocks at ,b>ano1 ,s]r>a1 & ,=io4 ,on ,m>* #bg?1 #ahhd1 at #b4g ,p4,m41 ano!r /rong %ock occurr$2 /ronge/ at ,s]r>a1 :]e ! %ock 0 subsultory & accompani$ by noise2 & less /rong1 ?\gh /ill subsultory1 at ,ciglio1 ,panza1 ,=io1 ,fiaiano1 & ,casamicciola1 & v slight at ,is*ia4 ,! s]ies seems to h end$ dur+ ! foll[+ summ]1 ) a slight %ock at ,casamicciola on ,july #ba/1 & a /rong] "o on ,july #bcrd1 felt f ,casamicciola on ! nor? to ,s]r>a on ! s\?4 ,mo/ ( ! aft]-%ocks mu/ h orig9at$ 9 ! neighb\rhood ( ,casamicciola1 b x is wor?y ( notice t m ?an "o c5tre 0 9 action4 ,sev]al 7 record$ at ,is*ia only4 ,o!rs1 z m5tion$ above1 affect$ *iefly ! s\? "p ( ! isl&1 & especially ! small t[ns ( ,s]r>a & ,fontana4 ,,*>act]i/ics ,,( ,,is*ian ,,e>?quakes4 ,aft] ! eruption ( #acjb1 !re succe$$ a p]iod ( comp>ative repose 9 ,is*ia4 ,! revival ( activity dates f #agfb1 &1 s9ce t ye>1 !re h be5 f\r great e>?quakes1 namely1 ^? ( #agif1 #ahbh1 #ahha1 & #ahhc4 ,9 e respect b t ( increas+ int5sity1 ^! e>?quakes 7 app>5tly id5tical2 ea*1 z ,pr(essor ,m]calli says1 0 m]ely a replica on a diff]5t scale ( ^? t prec$$ x4 ,! pr9cipal features 9 :i* !y resemble "o ano!r1 & diff] f ! av]age tectonic e>?quake1 are ! co9cid5ce ( ! epic5tres1 ! small dep? ( ! foci1 & ! sudd5 onset ( ! pr9cipal %ock4 #a4 ,co9cid5ce ( ,epic5tres4--,9 ,fig4 #ad1 :i* is copi$ f ,pr(essor ,m]calli's map1 are %[n ! areas 9 :i* build+s 7 s]i\sly damag$ by ^! f\r e>?quakes4 ,! curves = #agif1 #ahbh1 & #ahha are approximately conc5tric4 ,9 #agif1 ! %ock 0 disa/r\s only to ! we/ ( ,casamicciola2 9 #ahbh1 accord+ to ,covelli1 ! gr\nd mo/ injur$ 0 n precisely ! region ( ,casamicciola1 b t :i* lies betwe5 ! di/rict call$ ,fango & t kn[n z ,casam5ella1 situat$ to ! we/ ( ,casamicciola1 & a %ort di/ance f x4#bf ,! epic5tres may h v>i$ slightly 9 size1 b1 9 position1 x is cle> t all f\r 7 ne>ly or q co9cid5t4 ,! meizoseismal b&s 9 #ahha & #ahhc 7 also simil> 9 =m & elongat$ 9 ! same direction4 ,9 ! la/ two e>?quakes !re 01 z we h se51 v di/9ct evid5ce ( a second>y meizoseismal area surr\nd+ ,fontana1 & x is rem>kable t ?is 0 also noticeable 9 ! e>?quake ( #ahbh4 ,besides ! c5tre ( vibration 9 ! di/rict ( ,fango1 says ,covelli1 ano!r less p[]ful c5tre %[$ itself 9 ! locality ( ,fontana2 ?is made itself felt m heavily ?an 9 surr\nd+ localities2 z if ano!r c5tre ( movem5t _h tak5 place f t "p1 indep5d5t ( ! =m]4 #b4 ,small ,dep? ( ! ,foci4--,mallet's me?od1 z not$ above1 _c be tru/$ to yield accurate e/imates ( ! focal dep?1 or to indicate m ?an its ord] ( magnitude4 ,b x is rem>kable t ! dep?s calculat$ by ,dr4 ,john/on-,lavis = ! la/ two e>?quakes are bo? only a little less ?an a ?ird ( a mile1 & x is probable t ! actual dep? did n diff] v greatly f ?is am\nt4 ,! nature ( ! %ock1 v]tical or ne>ly s close to ! epic5tre & horizontal at a %ort di/ance f x1 is m]ely p]sonal te/imony ( ! same "* z fissures 9 masonry1 & ( c\rse po9ts to ! same result4 ,illu/ration3 ,,fig4 #ah4--;,diagram %[+ connection betwe5 dep? ( focus & rate ( decl9e 9 int5sity4 ,b ! mo/ conclusive evid5ce on :i* we h to rely is ! extraord9>y int5sity ( ! %ock at ! c5tre ( a v small di/ribut$ area4 ,9 ,great ,brita91 an e>?quake felt ov] a di/rict ( equal size w\ld h>dly at ! c5tre exce$ ! trembl+ produc$ 9 a /ation plat=m by a pass+ tra94 ,! curves 9 ,fig4 #ah %[ h[ ! rate ( decl9e 9 int5sity dep5ds on ! dep? ( ! focus4 ,!y are drawn on ! supposition t ! int5sity at any po9t on ! surface v>ies inv]sely z ! squ>e ( its di/ance f ! focus2 ! curves a1 b1 c correspond+ to foci situat$ at dep?s ( "o-?ird ( a mile1 "o mile1 & two miles respectively1 & ! figures bel[ ! horizontal l9e d5ot+ ! di/ance 9 miles f ! epic5tre4 ,?us1 ! rapid decl9e ( int5sity f ! epic5tre outw>ds %[s t1 9 ea* ( ! f\r great ,is*ian e>?quakes1 ! dep?s ( ! focus mu/ h be5 v small4 #c4 ,sudd5ness ( ! ,%ocks4--,9 #agif1 we h no record ( prep>atory %ocks1 b ! evid5ce is scanty2 9 #ahbh & #ahha1 none are m5tion$2 9 #ahhc1 "o or two tremors & und]gr\nd noises1 possibly ( seismic orig91 gave w>n+ to a few4 ,=e-%ocks1 = all practical purposes1 7 conspicu\s by _! abs5ce4 ,/ill m rem>kable is ! sudd5 adv5t ( ! great %ocks4 ,!re 7 no prelim9>y tremors or rumbl+ s\nd1 no animals %[$ signs ( uneas9ess & no birds flutt]$ scream+ f trees or gr\nd4 ,! %ock ( #ahbh1 says ,covelli1 0 ann\nc$ by ?ree p[]ful bl[s com+ almo/ v]tically1 f bel[ upw>ds2 & ! same words apply equally well to ! e>?quakes ( #ahha & #ahhc4 ,! de/ruction ( h\ses 9 e case 0 practically in/antane\s1 & co9cid5t ) ! fir/ vibration4 ,9 all respects1 tectonic e>?quakes diff] widely f ! ,is*ian %ocks4 ,! epic5tres ( successive e>?quakes are r>ely co9cid5t1 b %[ a di/9ct t5d5cy to migration along c]ta9 l9es2 ! decl9e 9 int5sity outw>ds f ! epic5tre is ne>ly always v gradual1 & !re=e indicative ( a comp>atively deep-seat$ focus2 !y are almo/ inv>iably prec$$ ei!r by a s]ies ( slight %ocks & rumbl+ s\nds1 or1 9 an un/able di/rict1 by a m>k$ increase 9 _! frequ5cy4 ,di/9ctions1 s great z ^! are1 evid5tly remove ! ,is*ian %ocks f ! category ( tectonic e>?quakes4 ,,orig9 ,,( ,,! ,,is*ian ,,e>?quakes4 ,on ! o!r h&1 ! ,is*ian e>?quakes possess sev]al features :i* connect !m closely ) true volcanic e>?quakes4 #a4 ,!y orig9ate b5ea? ! nor!rn slope ( ,epomeo--a volcano t we h no reason to consid] absolutely ext9ct1 b r z "o subject to eruptions at long int]vals ( "t--9 a region z yet unoccupi$ by p>asitic crat]s1 b hav+ ! same relation to ! c5tral cone ( ,epomeo z ^? 9 :i* ! rec5t crat]s ( ,monte ,rot>o1 ,montagnone & ,cremate are situat$4 #b4 ,9 bo? ! e>?quakes ( #ahha & #ahhc1 ! epic5tre is an elongat$ b&1 ! axis ( :i*1 if produc$1 w\ld pass ?r\gh ! c5tre ( ! old crat] ( ,epomeo4 ,along ! l9e ( ?is b&1 occur ! fum>oles ( ,monte ,cito & ,ignazio ,v]de & ! !rmal spr+s ( ! ,rita & ,capitello4 ,^! facts1 z ,pr(essor ,m]calli sugge/s1 lead u to believe t ! foci ( ! e>?quakes co9cide ) a radial fracture ( ! volcano1 ! c\rse ( :i*1 z trac$ by him1 is repres5t$ by ! cont9u\s l9e 9 ,fig4 #ad4bg #c4 ,except 9 _! relations ) actual eruptions1 ! ,is*ian e>?quakes resemble closely ! true volcanic e>?quakes :i* f "t to "t %ake ! flanks ( ,etna4 ,^! are m>k$ by great int5sity ( ! %ock at ! c5tre ( a comp>atively small di/urb$ area1 epic5tres (t5 elongat$ radially to ! cone1 frequ5t repetition ) simil> *>act]s 9 ! same di/ricts2 & z a rule !y prec$e by a %ort int]val1 b sometimes accompany or foll[1 volcanic eruptions4#bh ,two o!r ph5om5a may be ref]r$ to z probably indicat+ "s connection betwe5 ,is*ian e>?quakes & ! /ructure & hi/ory ( ,epomeo4 ,we h se5 t1 9 ! ?ree e>?quakes ( #ahbh1 #ahha1 & #ahhc1 !re is di/9ct evid5ce ( a second meizoseismal area at ,fontana1 )9 :i* ! %ock 0 ma9ly subsultory4 ,dr4 ,john/on-,lavis1 ?\gh recognis+ ! possibility ( ! exi/5ce ( two epic5tres1 pref]s ano!r explanation4#bi ,b ! wide ext5sion ( ! s\!rn b\nd>y ( ! area ( de/ruction 9 #ahhc1 & ! limitation ( sev]al ( ! aft]-%ocks to ! s\? ( ! isl&1 seem to me to fav\r ! exi/5ce ( a second focus b5ea? ! crat] ( ,epomeo1 ?\gh1 x may be1 n entirely deta*$ f ! *ief focus b5ea? ,casam5ella4 ,aga91 z ,pr(essor ,m]calli rem>ks1 all hi/oric eruptions on ! flanks ( ,epomeo 7 accompani$ by v viol5t e>?quakes2 :ile1 previ\sly to #acjb1 only "o disa/r\s e>?quake1 s f> z kn[n1 occurr$ 9 ! isl& )\t be+ att5d$ by an eruption4 ,x %\ld be notic$ also t ! pr9cipal %ocks dur+ ! rec5t revival ( activity 7i4e41 s9ce #agfb7 %[ a cont9ual increase 9 int5sity1 :e!r ?is be measur$ by ! damage to build+s1 ! loss ( life1 or ! ext5t ( ! area ( de/ruction 7,fig4 #ad74 ,x !re=e seems legitimate to conclude t1 9 ! rec5t ,is*ian e>?quakes1 we h m]ely s _m unsuccessful attempts to =ce a new volcanic eruption4 ,! passages once exi/+ ?r\gh ,epomeo & its p>asitic crat]s hav+ become block$1 ! highly heat$ magma b5ea? is compell$ to f9d a new outlet4 ,its t5sion sl[ly increas+1 ! cru/ above is at la/ r5t1 or an incipi5t r5t is enl>g$1 ! fluid rock is inject$ almo/ in/antane\sly ) great =ce into ! op5 fissure1 & its sudd5 arre/ by ! conta9+ walls is ! ultimate cause ( an e>?quake4 ,) ! expansion ( ! magma1 its t5sion is at once correspond+ly r$uc$1 & "s "t mu/ elapse be=e x c aga9 rea* ! critical po9t at :i* a fur!r rupture1 result+ 9 a second %ock1 takes place4#cj ,?us1 ) ea* great ,is*ian e>?quake1 we are1 ,i believe1 advanc+ a /ep ne>] ! "t1 :i* may be close at h& or may be v remote1 :5 ! fracture w at la/ rea* ! surface1 & above ! site ( ,casam5ella a new p>asitic cone w rise1 f :i*1 z f ,cremate 9 #acjb1 a /ream ( lava may fl[ d[n t[>ds ! sea4 ,,ref]5ces4 #a4 ,,baldacci1 ,l4--,alcune oss]vazioni sul t]remoto avv5uto all' ,isola d',is*ia il #bh luglio #ahhc4 ,ital4 ,com4 ,geol4 ,boll41 vol4 xiv41 #ahhc1 pp4 #aeg-aff4 #b4 ,,daubr,e1 ,a4--,rapport sur le tremblem5t de t]re ress5ti ,is*ia le #bh juillet1 #ahhc2 causes probables des tremblem5ts de t]re4 ,p>is1 ,acad4 ,sci41 ,compt4 ,r5d41 vol4 xcvii41 #ahhc1 pp4 #gfh-ggh4 #c4 ,,du ,,bois1 ,f4--,! ,e>?quakes ( ,is*ia4 ,japan ,seism4 ,soc4 ,trans41 vol4 vii41 pt i41 #ahhc-hd1 pp4 #af-db4 #d4 ---- ,f>!r ,notes on ! ,e>?quakes ( ,is*ia4 ,ibid41 vol4 viii41 #ahhe1 pp4 #ie-ii4 #e4 ,,john/on-,,lavis1 ,h4,j4--,monograph ( ! ,e>?quakes ( ,is*ia 7#ahhe74 #f4 ,,m]calli1 ,g4--,vulcani e f5om5i vulcanici 9 ,italia 7vol4 iii4 ( ,geologia d',italia1 by ,g4 ,negri1 ,a4 ,/oppani1 & ,g4 ,m]calli71 #ahhc1 pp4 #df-ej1 #cca-ccb4 #g4 ---- ,l',isola d',is*ia ed il t]remoto del #bh luglio #ahhc 7,milano1 #ahhd74 #h4 ,,palmi]i1 ,l41 ,e ,a4 ,,oglialoro4--,sul t]remoto dell' ,isola d',is*ia della s]a del #bh luglio #ahhc4 ,napoli1 ,r4 ,accad4 ,atti1 vol4 i41 #ahhd1 pp4 #a-bh4 #i4 ,,rossi1 ,m4,s4 ,,de4--,il t]remoto di ,casamicciola del #d m>zo #ahha4 ,bull4 del ,vulc4 ,ital41 anno viii41 #ahha1 pp4 #e-ab4 7,9 ! same volume are brief notices by diff]5t writ]s on pp4 #bb1 #ch-db1 #eb-ec1 #fg-fh1 #gj-gd47 #aj4 ---- ,raccolta di fatti1 relazioni1 bibliografie sul t]remoto di ,casamicciola del #bh luglio #ahhc1 con brevi oss]vazioni4 ,bull4 del ,vulc4 ,ital41 anno xi41 #ahhd1 pp4 #fe-agb4 #aa4 ---- ,intorno all' odi]na fase dei t]remoti 9 ,italia e segnatam5te sul t]remoto 9 ,casamicciola del #d ,m>zo #ahha4 ,ital4 ,soc4 ,geogr4 ,boll41 #ahha4 #ab4 ,,s]pi]i1 ,a4--,sul t]remoto d',is*ia il #bh luglio #ahhc4 ,scritti di ,sismologia1 ,pte4 ii41 pp4 #bjg-baf4 #ac4 ---- ,sul t]remoto dell' ,isola d',is*ia il #bh luglio #ahhc4 ,ibid41 pp4 #bag-bcb4 ,,footnotes3 #ba ,! %ad$ areas indicate ! pr9cipal tra*ytic masses1 ! brok5 l9es repres5t ! b\nd>ies ( ! crat]s t are /ill recognisable1 & ! dott$ l9es ! b\nd>ies ( ! areas )9 :i* build+s 7 damag$ by ! e>?quakes ( #agif1 #ahbh1 #ahha1 & #ahhc 7accord+ to ,m]calli74 ,! cont9u\s curv$ l9e %[s ! position ( ! radial fracture ) :i* ! e>?quakes 7 probably connect$4 ,! tra*ytic masses & crat]s are d5ot$ by ! foll[+ tables3-- a4 ,epomeo4 b4 ,trippiti4 c4 ,vetta4 d4 ,g>(oli4 e4 ,vatoli]e4 f4 ,campagnano4 g4 ,vezza4 h4 ,imp]atore4 i4 ,c4 ,/4 ,angelo4 j4 ,lo ,toppo4 k4 ,m>ecocco4 l4 ,zale4 m4 ,rot>o4 n4 ,montagnone4 p4 ,bagno4 q4 ,tabor4 r4 ,p4 ,ca/iglione4 s4 ,cremate4 t4 ,arso4 u4 ,porto d',is*ia4 #bb ,x is possible t ,monte ,campagnano may =m an exception to ?is /atem5t4 #bc ,%ocks 7 felt 9 ! isl& 9 #aeei & #afei1 b "o at lea/ 0 ( ext]nal orig94 #bd ,pr(4 ,m]calli1 f ! five e/imates ( ! angle ( em]g5ce :i* he consid]$ mo/ reliable1 f\nd ! mean dep? to be ab\t #c1bhj feet4 #be ,pr(essor de ,rossi e/imat$ ! mean duration z n mu* exce$+ t5 seconds4 ,dr4 ,john/on-,lavis1 on ! o!r h&1 consid]s ! g5]al e/imate ( fifte5 seconds z f> too l[4 ,9 "o case1 at ,casamicciola1 he ranks x z high z ?irty-"o seconds4 #bf ,quot$ f ! useful translation ( ,covelli's memoir giv5 by ,dr4 ,john/on-,lavis4 #bg ,baldacci supposes t ! !rmal spr+s & fum>oles ( ,=io1 ,/5nec*ia1 ,montecito1 ,casamicciola1 & ,ca/iglione lie along a tang5tial fracture />t+ f ,=io & pass+ by ,casamicciola to ne> ,punta di ,ca/iglione4 ,m]calli1 h[ev]1 argues =cibly aga9/ ?is inf]5ce4 #bh ,pr(essor ,m]calli adds1 z a f\r? po9t ( contact betwe5 ,is*ian e>?quakes & volcanic ph5om5a1 ! *anges 9 ! fum>oles & hot spr+s :i* prec$$ or accompani$ or foll[$ ! e>?quakes ( #ahbh1 #ahha1 & #ahhc4 #bi ,fontana1 he says1 occupies ! c5tre ( ! great crat] ( ,epomeo4441 & !re=e lies imm$iately ov] ! anci5t *imney1 :i* 9 all probability is fill$ by an old plug ( consolidat$ tra*yte1 :i* mu/ desc5d to ! igne\s res]voir4 ,any mass ( igne\s matt]1 t might det]m9e ! fur!r rupture ( a collat]al fissure1 w\ld result 9 ! conduction ( any *anges ( pressure or vibrations1 along ! column ( highly ela/ic tra*yte2 :il/ ! same e>?-waves w\ld be annull$ or absorb$ by ! inela/ic tufas surr\nd+ x1 s t ! bl[ w\ld be /ruck p]p5dicul>ly to ! surface1 & 9 a small area ) well def9$ limits4 ,! undulatory s5sations1 aft] ! pr9cipal local %ock1 7 ^? t arriv$ f ! great c5tre ( impulse b5ea? ,casam5ella4 #cj ,! above p>agraph is a summ>y ( ! reason+ /at$ ) admirable cle>ness by ,dr4 ,john/on-,lavis4 ,x %\ld be m5tion$ t ! late ,pr(essor ,palmi]i1 rely+ on ! extremely limit$ di/urb$ area1 diss5t$ f ?is view2 b 8 difficulty is met by suppos+ ! focus to be small z well z %all[1 a supposition t is support$ by ! %ortness ( ! meizoseismal b&1 z well z by ! elongation ( ! isoseismal l9es 9 ! direction p]p5dicul> to ?is b&4 ,,*apt] ,,iv4 ,,! ,,&alusian ,,e>?quake ,,( ,,decemb] #be,,?1 #ahhd4 ,9 mo/ c\ntries ! pr9cipal seismic di/ricts are ( limit$ ext5t4 ,?us1 9 c5tral ,japan1 ! ea/ coa/ is frequ5tly visit$ by e>?quakes1 :ile ! we/ coa/ is relatively undi/urb$4 ,( ! e>?quakes felt 9 ! k+dom ( ,greece dur+ ! ye>s #ahic-ih1 #fc p] c5t4 7 obs]v$ 9 ,zante1 & 7 = ! mo/ "p conf9$ to t isl&4 ,9 ! int]ior ( ! ,ib]ian p59sula--9 ,leon & 9 ,new & ,old ,ca/ile--de/ructive e>?quakes are practically unkn[n2 :ile ! littoral regions ( c5tral & s\!rn ,portugal1 ,&alusia1 & ,catalonia are not$ = _! disa/r\s %ocks4 ,dur+ ! eighte5? c5tury seismic activity 0 *iefly conc5trat$ 9 ,portugal1 & culm9at$ 9 ! great ,lisbon e>?quake ( #agee4 ,9 ! foll[+ c5tury ! seat ( di/urbance 0 transf]r$ f ! we/ to ! s\? ( ! p59sula2 ,portugal rema9$ ?r\gh\t 9 comp>ative repose1 :ile ,alm]ia exp]i5c$ de/ructive %ocks 9 #ahjd1 #ahfj1 & #ahfc1 & ,murcia 9 #ahbh-bi & #ahfd1 lead+ up to ! ,&alusian e>?quakes ( #ahhd-he1 describ$ 9 ! pres5t *apt]4 ,! prep>ation = ! pr9cipal e>?quake ( ,decemb] #be?1 #ahhd1 0 unusually indi/9ct4 ,= a day or two be=e1 %ocks 7 felt "h & !re 9 ,&alusia1 b s weak 7 !y t !y pass$ almo/ unp]ceiv$4 ,dur+ ! night ( ,decemb] #bd-be1 "o slight %ock 0 notic$ at ,colmear 7,fig4 #ai7 & ano!r at ,zaf>raya4 ,on ! #be?1 a fa9t movem5t ( ! gr\nd 0 notic$ at ,malaga1 & a few weak tremors at ,p]iana2 & %ortly aft] came ! great %ock at ab\t #h4ej ,p4,m4 mean "t ( ,malaga1 or ab\t #i4h ,p4,m4 ,gre5wi* mean "t4 ,?is e>?quake 0 inve/igat$ by no few] ?an ?ree (ficial committees4 ,! fir/ 9 ! field 0 nom9at$ by ! ,spani% ,gov]nm5t on ,janu>y #g?1 #ahhe1 & consi/$ ( f\r memb]s1 ! ,presid5t be+ ,seor ,m4,f4 de ,ca/ro1 ! director ( ! ,geological ,survey ( ,spa94 ,! report ( ?is commission 0 pres5t$ to ! ,m9i/] ( ,agriculture1 etc41 on ,m>* #ab?4 ,e>ly 9 ,febru>y a ,fr5* ,commission1 appo9t$ by ! ,academy ( ,sci5ces1 proce$$ to ! sc5e ( ! disa/]4 ,) ,pr(essor ,f4 ,f\qu z *ief1 & ,,mm4 ,lvy1 ,b]tr&1 ,b>rois1 ,(fret1 ,kilian1 ,b]g]on1 & ,bron z memb]s1 ?is committee resolv$ itself aft] a "t into "o = /udy+ ! geology ( ! c5tral area2 &1 ( _! volum9\s report ( m ?an #gjj qu>to pages 7publi%$ 9 #ahhi71 only #ee are imm$iately conc]n$ ) ! e>?quake4 ,at ! beg9n+ ( ,april1 ,pr(essors ,t>amelli & ,m]calli1 s5t by ! ,italian ,gov]nm5t1 arriv$ 9 ,&alusia2 & _! memoir1 read a few mon?s lat] be=e ! ,reale ,accademia dei ,l9cei1 =ms by f> ! mo/ valuable contribution to our k ( ! e>?quake4 ,,damage ,,caus$ ,,by ,,! ,,e>?quake4 ,! meizoseismal area 7see ,figs4 #ai & #bj7 lies 9 a m\nta9\s di/rict1 almo/ equidi/ant f ! cities ( ,malaga & ,granada4 ,9 ?is area1 :i* conta9s ne>ly #ijj squ>e miles1 ! %ock 0 disa/r\s to all b well-built h\ses4 ,:ole villages 7 ov]?r[n4 ,9 ! surr\nd+ zone _m build+s escap$ s]i\s damage1 & only a few 7 completely de/roy$4 ,x is e/imat$ by ! ,spani% ,commission t1 9 ! prov9ce ( ,granada1 #c1cdb h\ses 7 totally1 & #b1ach p>tially1 ru9$2 9 ! prov9ce ( ,malaga1 #a1jeg h\ses 7 totally1 & #d1agh p>tially1 ru9$2 :ile 9 ! two prov9ces toge!r #f1dfc h\ses 7 damag$2 mak+ a total ( #ag1agh build+s m or less s]i\sly injur$4 ,z usual 9 ! ,s\? ( ,europe1 bad con/ruction & n>r[ /reets 7 l>gely responsible = ! loss ( prop]ty1 h\ses t 7 regul>ly built & made ( good mat]ials be+ only slightly injur$4 ,b1 9 ?is case1 ! great slope ( ! gr\nd1 ! bad quality ( ! f\ndations1 & ! nature ( ! und]ly+ rocks 7 contribut+ factors4 ,_m build+s also _h be5 damag$ by previ\s %ocks1 & _! ru9 0 only complet$ by ! e>?quake ( #ahhd4 ,! total loss ( life is v>i\sly e/imat$4 ,accord+ to ! ,spani% ,commission1 #fij p]sons 7 kill$ & #a1dbf w\nd$ 9 ! prov9ce ( ,granada1 :ile #ee 7 kill$ & #ei w\nd$ 9 t ( ,malaga1 mak+ a total ( #gde p]sons kill$ & #a1dhe w\nd$4 ,! ,italian seismologi/s1 hav+ additional mat]ials at _! disposal1 raise ! total figures to #gej p]sons kill$ & #a1eed sev]ely w\nd$4 ,c>eful inquiries 7 also made on ?is subject by ! conductors ( ! newspap] ,el ,def5sor de ,granada4 ,9 ,granada alone1 !y reckon t #hbh p]sons 7 kill$ & #a1afd w\nd$4 ,f ! table giv5 9 ! ,italian report1 x appe>s t #ccj p]sons 7 kill$ at ,alhama1 #aah at ,ar5as del ,rey1 #ajb at ,albuuelas1 #gg at ,v5tas de ,zaf>raya1 & #dj at ,p]iana2 ! p]c5tage ( mortality be+ #i at ,ar5as del ,rey1 ab\t ! same at ,v5tas de ,zaf>raya1 & #c or #d at ,alhama1 ,albuuelas & ,p]iana4 ,comp>+ ^! latt] figures ) ! dea? rates ( #ga p] c5t4 at ,montemurro1 caus$ by ! ,neapolitan e>?quake1 & ( ab\t #de p] c5t4 at ,casamicciola1 by ! ,is*ian e>?quake ( #ahhc1 x w be se5 t ! loss ( life dur+ ! ,&alusian e>?quake 0 comp>atively small--an exemption :i* is attribut$ by ! ,italian commission]s to ! abs5ce ( inhabit$ places f ! imm$iate neighb\rhood ( ! epic5tre1 & to ! fact t ! de/ructive vibrations occurr$ t[>ds ! end ( ! %ock1 ?us all[+ opportunity = escape4 ,,isoseismal ,,l9es ,,& ,,di/urb$ ,,area4 ,fig4 #ai %[s ! pr9cipal isoseismal l9es z drawn by ! ,italian commission]s4 ,! meizoseismal area1 :i* includ$ all places at :i* ! %ock 0 disa/r\s1 is b\nd$ by an ellipse 7m>k$ #a on ! map7 #dj miles long f ea/ to we/1 #bh miles wide1 & ab\t #hhf squ>e miles 9 area4 ,! next isoseismal 7#b7 includes ! places 9 :i* "s build+s 7 ru9$1 b n z a rule completely1 & 9 :i* !re 0 no loss ( life4 ,its b\nd+ l9e is also elliptical1 ! long] axis be+ ab\t #ga miles long & runn+ ne>ly ea/ & we/4 ,t[>ds ! s\? ?is zone is int]rupt$ by ! sea4 ,x w be notic$ t ^! isoseismals are n conc5tric1 ! second ext5d+ mu* f>!r to ! we/ & s\?-we/ ?an 9 ! opposite direction4 ,a ?ird isoseismal 7n %[n 9 ! map7 encloses ! di/rict 9 :i* ! %ock 0 v /rong1 or j capable ( produc+ cracks 9 ! walls ( h\ses4 ,x is simil> 9 =m to ! second isoseismal1 rea*+ z f> z ,e/epone to ! s\?-we/1 ,osuna1 ,cordova1 & ,seville to ! we/1 ,ja5 to ! nor?1 :ile t[>ds ! ea/ x /ops %ort ( ,alm]ia4 ,illu/ration3 ,,fig4 #ai4--;,isoseismal l9es ( ,&alusian e>?quake4 7,t>amelli & ,m]calli47 ,! ,fr5* ,commission h also publi%$ a map ( ! e>?quake1 &1 ?\gh ! "w ( an exp]i5c$ seismologi/ l ,pr(essor ,m]calli is probably m tru/wor?y1 x is int]e/+ to comp>e 8 isoseismal l9es ) ^? obta9$ by 8 ,fr5* colleagues1 :i* are reproduc$ 9 ,fig4 #bj4 ,! curves 9 ?is figure are drawn s z to include ! places t 71 respectively1 ru9$1 s]i\sly damag$1 & slightly damag$1 by ! %ock4 ,!y %\ld !re=e correspond ) ! l9es 9 ,fig4 #ai4 ,x w be se5 t !y diff] consid]ably 9 =m1 b at ! same "t !y pres5t c]ta9 po9ts ( agreem5t1 su* z ! ea/ & we/ elongation ( ! meizoseismal area1 & ! great ext5sion ( ! two out] isoseismals t[>ds ! we/ & s\?-we/ ,! greate/ diff]5ce is to be f\nd 9 ! ea/]n portion ( ! ?ird isoseismal1 :i*1 accord+ to ! ,italians1 ext5ds beyond ! limits includ$ 9 ,fig4 #bj1 &1 accord+ to ! ,fr5*1 is bay$ back by ! great masses ( ! ,si]ra ,nevada4 ,outside ,&alusia ! e>?quake 0 s5sibly felt to ! nor? z f> z ,madrid & ,segovia1 to ! we/ at ,huelva1 ,crc]es & ,lisbon1 & to ! ea/ at ,val5cia & ,murcia4 ,t[>ds ! s\?1 ! great] "p ( ! di/urb$ area 0 cut (f by ! ,m$it]ranean1 & !re are no records =?com+ f ! opposite coa/ ( ,africa4 ,! total area di/urb$ by ! e>?quake is r\ghly e/imat$ by ! ,fr5* ,commission at ab\t #aed1jjj squ>e miles1 & by ! ,italian ,commission at ab\t #agd1jjj squ>e miles2 b1 z ! %ock 0 /rong en\gh to /op clocks & r+ bells at ,madrid1 x is evid5t t ev5 ! great] ( ^! values is too small4 ,illu/ration3 ,,fig4 #bj4--;,isoseismal l9es ( ,&alusian e>?quake4 7,f\qu1 etc47 ,,! ,,unfelt ,,e>?quake4 ,f> beyond ! limits ( ! di/urb$ area1 h[ev]1 ! long sl[ waves sp$ ov] ! surface1 di/urb+ magnetographs & o!r delicate in/rum5ts4 ,m ?an a c5tury be=e1 ! great ,lisbon e>?quake ( #agee _h caus$ oscillations 9 ,scotti% lakes1 & on o!r occasions ! effects ( remote e>?quakes _h be5 witness$ at isolat$ places4 ,b1 9 #ahhd1 ! concurr5t regi/ration ( ! ,&alusian e>?-waves at di/ant obs]vatories attract$ g5]al att5tion1 & 9 "p sugge/$ ! _w-wide network ( seismological /ations1 ! f\ndation ( :i* 0 laid be=e ano!r decade _h pass$4 ,9 ,italy1 probable records ( ! e>?quake 7 obta9$ at two obs]vatories1 b1 ow+ to ! approximate times giv51 _! connection ) x is n e/abli%$4 ,at ,velletri1 ne> ,rome1 ,pr(essor ,galli's seismodynamograph regi/]$ a v slight movem5t at #aj ,p4,m41 & at ,rome itself ,pr(essor de ,rossi f\nd a tromomet] mak+ unusual oscillations at #aj4ae ,p4,m4#ca ,! mo/ int]e/+ records1 h[ev]1 are ^? furni%$ by ! magnetographs at ,lisbon1 ,p>c ,sa9t-,maur 7ne> ,p>is71 ,gre5wi*1 & ,wilhelm%av54 ,at ,lisbon1 ! records are extremely cle>4 ,! curves ( ! decl9ation1 horizontal =ce & v]tical =ce magnets1 z se5 9 ,fig4 #ba1 are abruptly brok5 at #h4cc ,p4,m4 7,lisbon "t1 or #i;h4 #im4 #des41 ,g4,m4,t474 ,! di/urbances1 :i* are greate/ on ! decl9ation curve & lea/ on ! v]tical =ce curve1 la/$ 9 all ?ree = ab\t #ab m9utes1 & are q di/9ct f ! ord9>y magnetic p]turbations4 ,at ,p>c ,sa9t-,maur1 ! magnetographs seem to be ill-adapt$ to act z seismographs1 = only a slight m>k 0 discov]$ on a re-exam9ation ( ! curves1 beg9n+ at #i4bd ,p4,m4 7,p>is "t1 or #i;h4 #adm4 #cis41 ,g4,m4,t47 ,at ,gre5wi*1 ,mr4 ,w4 ,ellis writes1 !re 0 a small simultane\s di/urbance ( ! decl9ation & horizontal =ce magnets1 occurr+ at #i;h4 #aem4444 ,bo? magnets 7 at ?is "t set into slight vibration1 ! ext5t ( vibration 9 ! case ( decl9ation be+ ab\t #b' ( arc1 & 9 horizontal =ce equival5t to 4#jja ( ! :ole horizontal =ce ne>ly4 ,( ! ?ree in/rum5ts at ,wilhelm%av51 only "o %[$ any movem5t at ! "t ( ! e>?quake4 ,! decl9ation magnet 0 undi/urb$1 ! horizontal =ce curve 0 accid5tally int]rupt$1 b ! v]tical =ce curve indicat$ a v p]ceptible %ock4 ,beg9n+ at #i4eb ,p4,m4 7,wilhelm%av5 mean "t1 or #i;h4 #bim4 #bis41 ,g4,m4,t471 ! curve 0 brok5 = f\r m9utes1 = ! rapid sw++ ( ! ne$le c\ld n be regi/]$ until ! motion became fa9t]4 ,fur!r di/urbances also occurr$ at #i4ei1 #aj1 #aj4b1 & #aj4e ,p4,m4#cb ,illu/ration3 ,,fig4 #ba4--,magnetograph records ( ,&alusian e>?quake at ,lisbon4 7,f\qu1 etc47 ,,position ,,( ,,! ,,epic5tre4 ,! inn]mo/ isoseismal be+ too l>ge1 & ! "t-records too inaccurate1 to give ! position ( ! epic5tre1 bo? ,commissions resort$ to obs]vations ( ! direction1 ,pr(essor ,f\qu & 8 colleagues dep5d+ *iefly on ! oscillation ( hang+ lamps1 & ,pr(essors ,t>amelli & ,m]calli on ! fall or displacem5t ( /atues & o!r objects1 & all avoid+ z f> z possible ! evid5ce ( fissures 9 build+s4 ,! ,italian obs]v]s po9t out t1 among ! div]g5t directions visible at any place1 !re is g5]ally "o m di/9ctly m>k$ ?an ! o!rs1 & ?is1 !y consid]1 corresponds to ! movem5t com+ almo/ directly f ! c5tre ( di/urbance4 ,plott+ ^! directions 7#cf 9 numb]71 !y f9d t !y conv]ge z a rule )9 ! triangle =m$ by jo9+ ,v5tas de ,zaf>raya1 ,alhama1 & ,jat>1 :ile a l>ge numb] ( !m trav]se ! elliptical area1 ^: b\nd>y is repres5t$ by ! dott$ l9e 9 ,fig4 #ai4 ,?is area is ab\t #i miles long & #b-a_/b miles wide1 its long] axis runs ne>ly ea/ & we/1 & its c5tre co9cides ) ! we/]n focus ( ! ellipse :i* =ms ! b\nd>y ( ! meizoseismal area4 ,x lies1 moreov]1 close to ,v5tas de ,zaf>raya & ,ar5as del ,rey1 ! two places :]e ! seismic dea?-rate 0 highe/1 :ile its major axis almo/ co9cides ) ! l9e jo9+ !m4 ,! evid5ce ( hang+ lamps collect$ by ! ,fr5* ,commission 0 m consi/5t ?an t ( ! fall5 objects4 ,at e place1 ! plane 9 :i* ! lamps oscillat$ 0 ne>ly con/ant1 ! deviations be+ g5]ally attributable to irregul>ities 9 ! mode ( susp5sion4 ,! azimu?s aga9 int]sect )9 an elliptical area1 :i*1 accord+ to ! ,commission1 diff]s little f ! c5tral region ( ! e>?quake 7,fig4 #bj74 ,x ,is cle>1 h[ev]1 f ! map accompany+ ! ,fr5* report1 t ! majority conv]ge t[>ds a n>r[ b& ext5d+ ea/ & we/ f ne> ,ar5as del ,rey to ne> ,v5tas de ,zaf>raya1 & !re=e agree+ closely ) ! epic5tral area z det]m9$ by ,pr(essors ,t>amelli & ,m]calli4#cc ,,dep? ,,( ,,! ,,seismic ,,focus4 ,if ! dep? ( ! seismic focus am\nts to sev]al miles1 "o ( ! mo/ s]i\s objections to ,mallet's me?od lies 9 ! v>y+ refractive p[] ( ! diff]5t /rata trav]s$ by ! e>?-waves 7p4 #bh74 ,at pres5t we h no way ( meet+ ?is objection1 & all calculations ( ! dep? ( ! focus are !re=e m or less d\btful4 ,a difficulty 9 practice has also be5 urg$1 dep5d+ on ! widely diff]+ incl9ations ( ! fractures at any place2 b ! ,italian obs]v]s f\nd t ! errors f ?is s\rce 7 greatly r$uc$ by avoid+ all fissures 9 poorly-built h\ses1 or :i* />t f w9d[s or o!r ap]tures1 & select+ only ^? :i* occur 9 homog5e\s walls direct$ t[>ds ! epic5tre4 ,! be/ angles ( em]g5ce ?us measur$ by !m are ?irte5 9 numb]1 all made at places ly+ )9 #e & #bc miles f ! c5tre ( ! epic5tral area1 &1 ) two exceptions1 inside ! meizoseismal zone 7,fig4 #ai74 ,! dep?s correspond+ to ! diff]5t wave-pa?s v>y f #e4c to #bc4j miles1 ! mean dep? ( ! focus giv5 by all ?irte5 obs]vations be+ #g4f miles4 ,! only e/imate made by ! ,fr5* ,commission--& x is "o t !y rightly reg>d$ ) consid]able d\bt--0 bas$ on a me?od devis$ by ,falb4 ,z ! s\nd g5]ally prec$es ! %ock1 ,falb assumes t x travels ) a great] velocity4 ,if ! velocities ( bo? s]ies ( waves are kn[n1 & if !y />t at ! same in/ant & f ! same region1 ! int]val t elapses betwe5 ! arrivals ( ! s\nd & %ock %\ld give ! di/ance trav]s$ by !m & consequ5tly ! dep? ( ! focus4 ,x is unnecess>y to m5tion m ?an two ( ! s]i\s objections to ?is me?od4 ,! duration ( ! prelim9>y s\nd %\ld increase rapidly ) ! di/ance f ! focus1 & ( ?is !re is n ! slighte/ evid5ce4 ,moreov]1 ! s\nd-vibrations t are fir/ he>d d n necess>ily come f ! same "p ( ! focus z ^? :i* cause ! %ock1 b1 z w be se5 9 ,*apt] ,,viii41 probably f its ne>] lat]al m>g94 ,! ,fr5* ,commission1 f9d+ ! av]age duration ( ! =e-s\nd ne> ! epic5tre to be #e seconds1 e/imate ! dep? ( ! focus at ab\t #g miles--a result :i* agrees rem>kably ) t obta9$ f ! angles ( em]g5ce1 b :i* is n1 on t acc\nt1 entitl$ to cr$it4 ,,nature ,,( ,,! ,,%ock4 ,9 ! nature ( ! %ock1 !re 0 a s+ul> uni=mity ?r\gh\t ! :ole di/urb$ area1 ! *ief v>iation notic$ be+ evid5tly dep5d5t on ! obs]v]'s di/ance f ! epic5tre4 ,= in/ance1 9 ! meizoseismal area 7,fig4 #ai71 at ,v5tas de ,zaf>raya1 a l\d s\nd l ?und] 0 fir/ he>d1 & be=e x ceas$ !re came a viol5t subsultory movem5t prec$$ by a v brief oscillation1 !n a pause ( "o or two seconds1 & la/ly a m int5se & long] s]ies ( undulations1 ! :ole movem5t la/+ #ab seconds4 ,at ,cac91 ?ree phases 7 di/+ui%$1 ! fir/ a slight undulatory movem5t co9cid5t ) ! s\nd1 foll[$ imm$iately by ! subsultory motion1 a pause1 & /rong] undulations1 ! total duration be+ #ae seconds4 ,! v>iations noticeable 9 ?is zone seem to h be5 app>5t only1 s5sitive obs]v]s p]ceiv+ a tremul\s motion be=e ! v]tical vibrations1 & 9 ! pause betwe5 !m & ! conclud+ undulations4 ,9 bo? phases1 ! int5sity increas$ to a maximum & !n gradually decreas$4 ,! movem5t at ,v5tas de ,zaf>raya & ,cac9 is repres5t$ by ,pr(essors ,t>amelli & ,m]calli by ! curves a & b 9 ,fig4 #bb4 ,9 ! second zone 7,fig4 #ai71 ! same two phases 7 univ]sally obs]v$1 b ! subsultory movem5t 0 less pron\nc$ or ! movem5t 0 p>tly subsultory & p>tly undulatory1 & occasionally bo? phases are describ$ z undulatory4 ,! motion ne> ,malaga is repres5t$ by ! curve c 9 ,fig4 #bb4 ,illu/ration3 ,,fig4 #bb4--,nature ( %ock ( ,&alusian e>?quake4 7,t>amelli & ,m]calli47 ,outside ! ru9\s zone1 ! fir/ phase rapidly lo/ :at rema9$ ( its subsultory =m1 & ! pause betwe5 ! two p>ts 0 noticeably long] ?an ne> ! epic5tre4 ,?us1 at ,seville & ,cordova1 two %ocks 7 felt1 sep>at$ by an int]val ( "s seconds2 ! second accord+ to "s obs]v]s at ,seville1 t]m9at+ ) v]tical tremors4 ,at ,madrid1 also1 ! two p>ts 7 p]ceiv$1 ! int]val betwe5 !m be+ #c or #d seconds 9 l5g?2 b1 z a rule1 outside ,&alusia1 only a s+le undulatory %ock 0 felt1 )\t any prelim9>y s\nd4 ,t ! *anges obs]v$ 9 ! %ock 7 m]ely an effect ( less or great] di/ance1 w be obvi\s f ,fig4 #bc1 9 :i* ! int5sity at any mom5t is t repres5t$ by ! di/ance ( ! correspond+ po9t on ! curve f ! diff]5t base-l9es1 ! base-l9e a correspond+ to a place ne> ! epic5tre1 & b1 c1 d1 etc41 to places at gradually increas+ di/ances4 ,?us1 at a place correspond+ to ! base-l9e b1 ! int5sity ( ! tremors dur+ ! int]v5+ pause 7repres5t$ by ! %ort l9e ,,pn7 0 s slight t !y frequ5tly escap$ notice1 :ile ! prelim9>y tremors obs]v$ by "s ne> ! epic5tre 7 altoge!r imp]ceptible4 ,at ! places correspond+ to ! base-l9es c1 d1 e1 f1 ! duration ( ! :ole %ock & ( ea* "p gradually dim9i%$1 :ile ! int]val betwe5 ! two p>ts increas$ ow+ to ! gradual ext9ction ( ! f9al vibrations ( ! fir/ "p & ( ! initial vibrations ( ! second4 ,at ! f>!/ ( ^! places 7f7 ! fir/ "p 0 s weak t x sometimes pass$ unobs]v$4 ,la/ly1 at a place correspond+ to ! base-l9e g1 ! fir/ "p 0 imp]ceptible to all obs]v]s1 & ! %ock consi/$ ( a s+le s]ies ( horizontal undulations4 ,illu/ration3 ,,fig4 #bc4--;,diagram to illu/rate v>iation 9 nature ( %ock ( ,&alusian e>?quake4 ,orig9 ( ! ,d\ble ,%ock4--,if ! d\ble %ock 7 obs]v$ at only a few places1 we %\ld naturally look = "s local explanation ( ! peculi>ity4 ,! second %ock1 = in/ance1 might be a subt]ranean e*o1 ! e>?-waves be+ reflect$ at ! b\nd+ surface ( two diff]5t k9ds ( rock4 ,9 ! case ( ! ,&alusian e>?quake1 su* an explanation is preclud$ by ! almo/ univ]sal obs]vation ( ! d\ble %ock1 ! great] int5sity ( ! second "p1 & ! long] p]iod ( its vibrations4 ,! ,italian obs]v]s1 :o paid consid]able att5tion to ! d\ble %ock1 give a m g5]al explanation4 ,!y reg>d ! two p>ts ( ! %ock z correspond+ 9 ! ma9 to longitud9al & transv]sal waves />t+ simultane\sly f ! same focus 7see p4 #ac74 ,! =m] vibrations w\ld be v]tical at ! epic5tre & w\ld gradually become horizontal 9 spread+ outw>ds2 ! latt] w\ld be horizontal at ! epic5tre & at a di/ance f x 7e4g4 at ,seville7 ne>ly v]tical4 ,also1 z ! longitud9al waves travel m rapidly ?an o!rs1 ! int]val betwe5 ! two p>ts ( ! %ock w\ld increase ) ! di/ance f ! orig94 ,ow+ aga91 to ! l>ge size ( ! focus1 ! fir/ "p ( ! %ock w\ld at no place be in/antane\s1 & its lat] vibrations might coalesce ) ! e>li] transv]se vibrations1 s t1 )9 & ne> ! meizoseismal area1 ! second "p ( ! %ock might be /rong] ?an ! fir/4 ,a simil> result might be produc$ 9 ! same di/rict if ! transv]se vibrations co9cid$ ) reflect$ longitud9al vibrations1 & ,pr(essors ,t>amelli & ,m]calli ?9k t su* reflection w\ld occur f ! old cry/all9e rocks ( ! ,si]ra de ,almij>a & possibly also f ! calc>e\s & cry/all9e rocks to ! s\?-we/ ( ,c>tama4 ,satisfactory z x seems to be 9 "s respects1 ?is explanation is op5 to s]i\s objections1 ( :i* ,i w m5tion only two4 ,! fir/ is t1 ?\gh ! pause betwe5 ! two p>ts ( ! %ock does increase ) ! di/ance1 x does n increase rapidly en\gh2 at ,seville1 x %\ld be two or ?ree m9utes1 in/ead ( "s seconds 9 l5g?4 ,a m fatal objection1 h[ev]1 is t1 if ! explanation 7 correct1 e e>?quake-%ock %\ld consi/ ( two p>ts1 & ?is is only ! case ) a small m9ority4 ,on ! o!r h&1 if ! velocities ( ! waves compos+ ea* "p 7 ! same1 ! slight increase 9 ! l5g? ( ! int]val is readily acc\nt$ =1 z we h se51 by ! gradual ext9ction ( its weak t]m9al vibrations4 ,b 9 any case1 ! long int]val t elaps$ betwe5 ! beg9n+s ( ! two p>ts at a place s ne> ! epic5tre z ,v5tas de ,zaf>raya1 %[s t ea* "p 0 due to a di/9ct impulse2 &1 judg+ f ! directions ( ! respective movem5ts1 x w\ld seem t ! focus ( ! fir/ impulse 0 situat$ at a great] dep? ?an ! focus ( ! second4 ,:e!r ! epic5tres correspond+ to ! two foci 7 co9cid5t or m or less sep>ate is n cle> f ! nature ( ! %ock2 b x is probable t !y 7 ne>ly or q deta*$1 & t a second epic5tre 0 situat$ ne> ! ea/]n focus ( ! ellipse b\nd+ ! meizoseismal area4 ,,s\nd-,,ph5om5a4 ,9 ! ,neapolitan e>?quake1 ! s\nd 0 only he>d 9 a di/rict ( ab\t #c1cjj squ>e miles imm$iately surr\nd+ ! epic5tres1 :ile ! :ole area di/urb$ by ! %ock 0 n less ?an #ci1jjj squ>e miles4 ,a simil> limitation 0 notic$ 9 ! ,&alusian e>?quake4 ,accord+ to ! ,spani% ,commission1 ! s\nd 0 he>d at only "o place 7,cordova7 outside ! prov9ces ( ,granada & ,malaga2 & its audibility 0 a rule conf9$ to ! area )9 :i* build+s 7 damag$ by ! %ock4 ,x 0 comp>$ at diff]5t places to ! noise ( a pass+ tra9 or a c>riage heavily lad5 runn+ on a pav$ road1 ( di/ant ?und]1 a great /orm1 or ! dis*>ge ( heavy guns4 ,at e place :]e ! s\nd 0 he>d1 x di/9ctly prec$$ ! %ock1 frequ5tly all[+ "t = escape f h\ses t 7 aft]w>ds ru9$4 ,its duration )9 ! meizoseismal area 0 on an av]age ab\t five or six seconds1 r>ely p]haps did x exce$ t5 seconds4 ,at "s places 9 ! same area1 x ov]lapp$ ! beg9n+ ( ! %ock1 b g5]ally x 0 sep>at$ f ! latt] by a v %ort int]val1 e/imat$ at a second4 ,f ?is prec$5ce ( ! s\nd1 ! ,italian ,commission conclude t ! s\nd-waves travell$ m rapidly ?an ^? :i* =m$ ! %ock1 an inf]5ce t dep5ds on ! assumption t bo? waves />t$ simultane\sly f )9 precisely ! same focal limits4 ,a diff]5t explanation1 n bas$ on ^! assumptions1 w be consid]$ m fully 9 ,*apt] ,,viii1 deal+ ) ! rec5t e>?quakes ( ,h]e=d & ,inv]ness4 ,,velocity ,,( ,,! ,,e>?-,,waves4 ,if1 9 a highly-civilis$ c\ntry1 ! "t-records ( an e>?quake v>y )9 wide limits1 x is n surpris+ t ^? giv5 = ! ,&alusian e>?quake %\ld be :olly untru/wor?y4 ,ev5 ! clocks 9 public build+s & railway /ations diff]$ by z mu* z #be m9utes 9 _! indications4 ,an int]e/+ obs]vation is1 h[ev]1 describ$ 9 ! ,fr5* report & is wor? repeat+1 ?\gh x does n lead to any accurate result4 ,at ! "t ( ! pr9cipal %ock1 two telegraph-cl]ks 7 9 communication1 "o at ,malaga & ! o!r at ,velez-,malaga4 ,! latt]1 surpris$ by ! %ock1 sudd5ly /opp$ 8 message2 &1 ab\t six seconds lat]1 ! arrival ( ! e>?-waves at ,malaga expla9$ ! int]ruption to 8 colleague4 ,z1 accord+ to ! ,fr5* report1 ,velez-,malaga is #i kms4 7or ab\t #e-a_/b miles7 ne>] ?an ,malaga to ! mean epic5tral po9t1 x foll[s t ! velocity ( ! e>?-waves mu/ h be5 ab\t #a4e kms41 or ne>ly a mile1 p] second4#cd ,! only obs]vations ( any real value 9 det]m9+ ! velocity are ^? giv5 by ! /opp$ clock at ! obs]vatory ( ,san ,f]n&o 7,cadiz7 & by ! magnetographs at ,lisbon1 ,p>c ,sa9t-,maur1 ,gre5wi*1 & ,wilhelm%av54 ,tak+ ! times at ,cadiz1 ,lisbon1 ,gre5wi*1 & ,wilhelm%av5 at #i4ah1 #i4ai1 #i4be1 & #i4bi ,p4,m4 respectively 7,p>is mean "t7 & ! mean epic5tral po9t z co9cid+ ) ,alhama1 ! ,fr5* ,commission e/imates r\ghly ! mean surface-velocity betwe5 ,cadiz & ,lisbon at #c4f kms4 p] second1 betwe5 ,cadiz & ,gre5wi* at #d4e kms4 p] second1 betwe5 ,cadiz & ,wilhelm%av5 at #c4a kms4 p] second1 & betwe5 ,gre5wi* & ,wilhelm%av5 at #a4f kms4 p] second4 ,dr4 ,agam5none1 h[ev]1 notices t ! di/ances f ,alhama are n correctly measur$1 & sub/itutes = ! above figures #d4hc1 #c4dc1 #b4hb1 & #a4ge kms4 p] second respectively4 ,^! results app>5tly %[ a decrease 9 ! velocity ) ! outw>d spread ( ! e>?-waves1 b1 z ,dr4 ,agam5none aga9 po9ts out1 a comp>atively small error 9 ! "t at ,cadiz w\ld neutralise ! app>5t decrease4 ,x is n to be suppos$ t ! a/ronomical clock at ?is obs]vatory 0 wrong by m ?an a second or two1 b ! behavi\r ( clocks dur+ an e>?quake is s irregul>--"s /opp+ at once1 o!rs /agg]+ on = "s seconds be=e arre/--t ! ,cadiz "t may diff] f ! true "t by sev]al seconds4 ,besides ?is possible error1 !re is also consid]able unc]ta9ty 9 ! records f ! magnetic obs]vatories1 ow+ to ! sl[ rate at :i* ! photographic pap] travels4 ,at ,p>c ,sa9t-,maur ?is rate is only #aj mm4 p] h\r1 & at ! o!r obs]vatories ab\t #ae mm4 p] h\r4 ,all[+1 !re=e1 = an error ( half-a-m9ute 9 ! "t-record at ,cadiz1 ( "o m9ute 9 ^? ( ,lisbon1 ,gre5wi*1 & ,wilhelm%av51 & ( two m9utes 9 t at ,p>c ,sa9t-,maur1 & tak+ ! mean epic5tral po9t z det]m9$ by ! ,italian obs]v]s1 ,dr4 ,agam5none1 apply+ ! me?od ( lea/ squ>es1 f9ds ! probable value ( ! velocity ( propagation to be #c4ae kms4 7or ne>ly #b miles7 p] second1 ) a possible error ( 4#ai kms4 p] second4 ,?is result agrees closely ) ! value f\nd = ! long sl[ undulations ( m rec5t e>?quakes4 ,,miscellane\s ,,ph5om5a4 ,connection betwe5 ,geological ,/ructure & ! ,int5sity ( ! ,%ock4--,:ile a great "p ( ! injury to build+s mu/ be attribut$ to _! faulty con/ruction1 ! connection betwe5 ! nature ( ! und]ly+ rock & ! am\nt ( damage 0 v cle>ly m>k$4 ,o!r conditions be+ ! same1 h\ses built on alluvial gr\nd suff]$ mo/ ( all2 & ! de/ruction 0 also great 9 ^? /&+ on s(t s$im5t>y rocks su* z clays & friable lime/ones4 ,on ! o!r h&1 :5 compact lime/ones or anci5t s*i/s =m$ ! f\ndation-rock1 ! am\nt ( damage 0 conspicu\sly less ?an 9 o!r cases4 ,! memb]s ( bo? ! ,fr5* & ! ,italian ,commissions agree 9 ascrib+ ! peculi> =m & relative positions ( ! isoseismal l9es to geological conditions4 ,to ! ea/ ( ! epic5tre1 ! s*i/s & cry/all9e lime/ones =m a deep1 uni=m1 & compact mass2 :ile1 to ! we/1 ! old cry/all9e rocks are cov]$ by jurassic1 cretace\s1 & eoc5e =mations1 con/itut+ a less homog5e\s & less ela/ic mass1 9 :i* ! int5sity ( ! %ock w\ld fade (f mu* m rapidly1 ) ! result t ! epic5tre occupies ! we/]n focus ( ! elliptical b\nd>y ( ! meizoseismal area 7,fig4 #ai74ce ,t m\nta9-ranges h an important influ5ce on ! =m ( isoseismal l9es is evid5t f bo? maps 7,figs4 #ai & #bj71 b especially f t publi%$ by ! ,fr5* ,commission 7,fig4 #bj74 ,! resi/ance (f]$ by ! ,si]ra ,nevada to ! propagation ( ! e>?-waves is %[n 9 ! =m] map by ! approximation ( ! fir/ & second isoseismals at ! ea/ end1 & 9 ! latt] by ! great bay 9 ! ?ird isoseismal l9e4 ,:i*ev] int]pretation ( ! evid5ce is ! m accurate1 ! action ( ! m\nta9\s mass is cle>ly to less5 rapidly ! int5sity ( ! %ock--an effect :i* is probably due to ! abrupt *anges 9 ! direction & nature ( ! /rata enc\nt]$ normally by ! e>?-waves4 ,on ! opposite side ( ! epic5tre1 ! waves meet ! ,si]ra de ,ronda obliquely4 ,9 trav]s+ ?is range1 ! %ock lo/ a great "p ( its /r5g?1 :ile x cont9u$ to be felt sev]ely along its ea/]n foot1 ?us giv+ rise to ! s\?-we/]ly ext5sion ( ! ?ird isoseismal 9 ,fig4 #bj1 &1 ?\gh to a less ext5t1 t ( ! second 9 ,fig4 #ai4 ,fissures1 ,l&slips1 etc4--,! e>?quake result$ 9 _m sup]ficial *anges1 su* z fissures1 l&slips1 & d]angem5t ( ! und]gr\nd wat]-sy/em--all *anges ( ! same ord] z ! de/ruction ( build+s--b1 s f> z kn[n1 9 no fault-sc>ps or o!r ext]nal evid5ce ( deep-seat$ movem5ts4 ,"s ( ! fissures 7 ( great l5g?4 ,"o ( ! mo/ rem>kable occurr$ at ,guevej>1 a village built on ! s\?-we/ slope ( ! ,si]ra de ,cogollos4 ,x 0 9 ! =m ( a horse-%oe1 & 0 ab\t two miles long1 f t5 to fifty feet wide1 & ( great dep?4 ,9 its neighb\rhood1 innum]able small cracks appe>$1 "s p]p5dicul> & o!rs p>allel to ! great fissure4 ,! gr\nd )91 a b$ ( clay re/+ on lime/one1 also slid d[n t[>ds ! riv]4 ,h\ses ne> ! c5tre ( ! fissur$ tract 7 %ift$ z mu* z ?irty y>ds )9 ! fir/ mon?1 & o!rs ne> its extremity ab\t t5 feet2 :ile ! accumulation ( ! mat]ial at ! s\? end ( ! fissure result$ 9 ! =mation ( a small lake1 ( ab\t #bej to #cej squ>e y>ds 9 area & ab\t #cj feet deep4 ,all /reams )9 ! fissur$ zone disappe>$1 & ! spr+1 :i* provid$ ! dr9k+-wat] ( ! village1 ceas$ to fl[4 ,! und]gr\nd wat]-sy/em 0 g5]ally affect$ ?r\gh\t ! c5tral area4 ,9 "s places1 m9]al spr+s disappe>$2 9 o!rs1 new spr+s broke out or old ones fl[$ m abundantly4 ,at ,alhama1 ! increas$ fl[ 0 accompani$ by a p]man5t rise 9 temp]ature f #dg to #ej ,c41 & by a m>k$ *ange 9 "*4 ,,aft]-,,%ocks4 ,frequ5t aft]-%ocks are a *>act]i/ic ( ! e>?quakes ( ,s\!rn ,spa94 ,aft] ! ,cordova e>?quake ( #aagj1 !y cont9u$ = at lea/ ?ree ye>s4 ,! ,murcian e>?quake ( #ahbh 0 foll[$ by #cjj m9or %ocks dur+ ! next tw5ty-f\r h\rs1 & = m ?an a ye> slight tremors 7 (t5 felt4 ,= "s "t aft] ! great e>?quake ( #ahhd1 ! movem5ts ( ! gr\nd 7 extremely num]\s 9 ! imm$iate neighb\rhood ( ! epic5tre1 f>!r away !y 7 r>] & ( less int5sity1 & outside ! area ( damag$ build+s !y 7 ne>ly abs5t4 ,?us1 dur+ ! night ( ,decemb] #be-bf1 #aaj aft]-%ocks 7 c\nt$ at ,jat>1 f #ad to #ag at ,alcauc91 ,v5tas de ,huelma1 ,motril1 ,cac91 ,durcal1 ,malaga1 etc42 ab\t #aa at ,la ,mala & ,albuuelas2 #i at ,velez-,malaga & ,l5teje2 & f #e to #g at ,frigiliana1 ,riogordo1 & ,c>tama4 ,! /ronge/ ( ^! %ocks occurr$ at #b4bj ,a4,m41 &1 ?\gh none 0 viol5t1 sev]al help$ to complete ! ru9 ( _m h\ses t _h be5 damag$ by ! pr9cipal %ock4 ,f ?is "t1 aft]-%ocks occurr$ almo/ daily until ! end ( ,may1 aft] :i* !y became mu* less frequ5t4 ,accord+ to ! li/ giv5 9 ! ,italian report1 :i* closes at ! end ( ,janu>y #ahhf1 #bcg %ocks 7 felt1 #bc up to ! end ( ,decemb]1 #cj 9 ,janu>y #ahhe1 #be 9 ,febru>y1 #bg 9 ,m>*1 #df 9 ,april1 & #dc 9 ,may4 ,9 ,june #ahhe1 only ?ree are record$1 & ! av]age numb] dur+ ea* ( ! foll[+ sev5 mon?s lies betwe5 five & six4 ,?is li/1 h[ev]1 does n include ! v weak %ocks1#cf = ne>ly all ^? conta9$ 9 x 7 felt z f> z ,malaga or its neighb\rhood4 ,! %ocks v>i$ consid]ably 9 int5sity z well z 9 frequ5cy1 five ( !m be+ mu* m viol5t ?an ! re/4 ,"o t occurr$ on ,decemb] #cj? 0 felt /rongly 9 all ! damag$ area1 two o!rs on ,janu>y #crd & #e? caus$ fre% injury to build+s1 a f\r?1 on ,febru>y #bg?1 di/urb$ an area b\nd$ r\ghly by ! second isoseismal ( ! pr9cipal e>?quake 7,fig4 #ai71 :ile ! fif? & /ronge/1 t ( ,april #aa?1 0 felt ov] a l>ge "p ( ! zone beyond4 ,at places )9 & ne> ! meizoseismal area1 e>?-s\nds 7 sometimes he>d )\t any s5sible %ock2 occasionally1 also1 tremors 7 felt ) no att5dant s\nd2 b1 z a rule1 ! %ocks 7 accompani$ by s\nd1 & 9 e su* case1 z 9 ! pr9cipal e>?quake1 ! s\nd prec$$ ! %ock1 or at mo/ 0 p>tly contemporane\s ) x4 ,sev]al ( ! aft]-%ocks resembl$ ! pr9cipal e>?quake 9 _! division into two p>ts sep>at$ by an int]val ( re/ or weak] movem5t f half a second to a second 9 l5g?1 ?\gh ! :ole duration ( ! %ock itself 9 no case exce$$ five or six seconds4 ,occasionally1 ! lik5ess 0 /ill clos]1 9 ! succession ( s\nd1 subsultory motion & conclud+ horizontal undulations4 ,,geology ,,( ,,! ,,meizoseismal ,,area ,,& ,,orig9 ,,( ,,! ,,e>?quakes4 ,! meizoseismal area & surr\nd+ zones lie 9 ! mid/ ( ! m\nta9\s region t sep>ates ! bas9 ( ! ,guadalquiv] f t ( ! ,m$it]ranean1 ! ess5tial /ructure ( :i*1 accord+ to ! geologi/s ( ! ,fr5* ,commission1 is outl9$ 9 ,fig4 #bd4 ,9 ?is sket*-map1 ! lightly-%ad$ b&s correspond to an upp] s]ies ( cry/all9e s*i/s1 & ! cross-%ad$ b&s to ! l[] s]ies ( mica-s*i/s & dolomites t =m ! anticl9al folds ( ! ,si]ra de ,ronda1 ! ,si]ra de ,mijas1 & ! ,si]ra ,tej$a4 ,9 addition to ! fault+ & int5se fold+ 9 ! direction ( _! /rikes1 ^! rocks are also int]sect$ by ?ree ne>ly p>allel transv]se faults ( po/-,triassic age1 :i*1 aid$ by subsequ5t d5udation1 h cut up ! :ole range into a numb] ( di/9ct si]ras4 ,!y are repres5t$ by ! brok5 l9es 9 ,fig4 #bd4 ,illu/ration3 ,,fig4 #bd4--,/ructure ( meizoseismal area ( ,&alusian e>?quake4 7,f\qu1 etc47 ,"o ( ^! faults1 t :i* passes ne> ,motril1 trav]ses ! meizoseismal area1 ^: b\nd>y1 z laid d[n by ! ,fr5* ,commission1 is indicat$ by ! dott$ l9e on ! sket*-map4#cg ,9 ! neighb\rhood ( ,zaf>raya1 ! fault int]sects ! brok5 anticl9al fold ( ! ,si]ra ,tej$a1 & ! epic5tre is ?us situat$ 9 "o ( ! mo/ di/urb$ tracts ( ! :ole region4 ,! evid5ce1 bo? seismic & geological1 is insuffici5t to support any precise view z to ! orig9 ( ! e>?quake1 b !re c be little d\bt t x 0 closely connect$ ) movem5ts along "o or m ( ! sy/em ( faults t int]sect n f> f ,zaf>raya4 ,,ref]5ces4 #a4 ,,agam5none1 ,g4--,alcune consid]azioni sui diff]5t metodi f9o ad oggi adop]ati nel calcol>e la velocit di propagazione del t]remoto &aluso del #be dicembre #ahhd4 ,roma1 ,r4 ,accad4 ,l9cei1 ,r5d41 vol4 iii41 #ahid1 pp4 #cjc-caj4 #b4 ---- ,velocit sup]ficiale di propagazione delle onde sismi*e 9 occasione della gr&e scossa di t]remoto dell' ,&alusia del #be dicembre #ahhd4 ,ibid41 vol4 iii41 #ahid1 pp4 #cag-cbe4 #c4 ,,ca/ro1 ,m4,f4 de4--,t]remotos de ,&aluca3 ,in=me de la comision nombrada p>a su e/udio d&o cu5ta del e/ado de los trabajos en #g de m>zo de #ahhe4 7,madrid1 #ahhe2 #ajg pp47 #d4 ,,f\qu1 ,f41 etc4--,mission d',&al\sie3 tudes relatives au tremblem5t de t]re du #be dcembre #ahhd1 et la con/itution gologique du sol branl p> les sec\sses4 ,p>is1 ,acad4 ,sci4 ,mm41 vol4 xxx41 pp4 #a-ggb4 #e4 ,,macph]son1 ,j4--,tremblem5ts de t]re en ,espagne4 ,p>is1 ,acad4 ,sci41 ,compt4 ,r5d41 vol4 c41 #ahhe1 pp4 #cig-cii4 #f4 ,,nogu,s1 ,a4,f4--,phnomnes gologiques produits p> les tremblem5ts de t]re de l',&al\sie1 du #be dcembre #ahhd au #af janvi] #ahhe4 ,ibid41 pp4 #bec-bef4 #g4 ,,rossi1 ,m4,s4 de4--,gli odi]ni t]remoti di ,spagna ed il loro eco 9 ,italia4 ,bull4 ,vulc4 ,ital41 anno xii41 #ahhe1 pp4 #ag-ca4 #h4 ,,t>amelli1 ,t41 & ,g4 ,,m]calli4--,i t]remoti ,&alusi com9ciati il #be dicembre #ahhd4 ,roma1 ,r4 ,accad4 ,l9cei1 ,mem41 vol3 iii41 #ahhe1 pp4 #aaf-bbb4 #i4 ,p>is1 ,acad4 ,sci41 ,compt4 ,r5d41 vol4 c41 #ahhe1 pp4 #bd-bg1 #acf-ach1 #aif-aig1 #bef-beg1 #eih-fja1 #aaac-aabj1 #adcf 7! la/ ?ree by ,f4 ,f\qu74 ,,footnotes3 #ca ,^! times correspond to ab\t #i4aj & #i4be ,p4,m41 ,gre5wi* mean "t4 ,! e>?quake /opp$ a clock at ! ,royal ,obs]vatory ( ,san ,f]n&o 7,cadiz71 at #h;h4 #dcm4 #ed4es4 mean local "t1 correspond+ to #i;h4 #hm4 #dds41 ,g4,m4,t4 #cb ,! e>?quake is also said to h be5 regi/]$ at ! obs]vatory ( ,moncali]i1 ne> ,tur91 b ,i h n be5 able to asc]ta9 ! "t ( occurr5ce4 ,a movem5t felt at ab\t #aj4bj ,p4,m4 at ,ramsbury1 9 ,wilt%ire1 0 attribut$ to ! e>?quake1 ?\gh ! "t is ab\t an h\r too late4 ,on ,decemb] #bf?1 an a/ronomical clock 0 /opp$ at ,brussels & its pill> displac$2 &1 on ! ev5+ ( ! same day1 ! l>ge telescope at ! obs]vatory 0 also f\nd to h be5 %ift$4 ,^! effects1 x is sugge/$1 7 caus$ by ! ,&alusian e>?quake1 b ! connection betwe5 !m seems to me v d\btful4 #cc ,! ,fr5* obs]v]s h also appli$ a me?od dep5d+ on ! "t ( occurr5ce ( ! %ock4 ,jo9+ places :]e ! record$ times 7 ! same1 !y notice t ! p]p5dicul> bisectors ( ^! l9es int]sect )9 an area :i* agrees practically ) t det]m9$ by ! azimu?s4 ,! inaccuracy ( ! "t-records mu/1 h[ev]1 less5 ! significance ( ?is result4 #cd ,dr4 ,agam5none po9ts out t1 accord+ to ! ,italian report1 ! diff]5ce 9 di/ance is #bb kms4 7or #ac-c_/d miles71 lead+ to a velocity ( ab\t #c4f kms41 or #b4c miles p] second4 #ce ,x %\ld be rememb]$ t x is n improbable t !re 7 two deta*$ epic5tres1 co9cid+ r\ghly ) ! two foci ( ?is curve4 #cf ,only eight are record$ dur+ ! night ( ,decemb] #be-bf4 ,on sev]al occasions dur+ ,april & ,may #ahhe1 gr\ps ( slight %ocks 7 felt2 b z _! individual times are n giv51 !y are reg>d$ z equival5t to "o %ock ea* 9 ! above totals4 #cg ,! b\nd>y1 z drawn 9 ?is figure1 diff]s slightly f t giv5 9 ,fig4 #bj4 ,,*apt] ,v4 ,,! ,,*>le/on ,,e>?quake ,,( ,,augu/ #ca,,/1 #ahhf4 ,! ,*>le/on e>?quake /&s alone among ! great e>?quakes describ$ 9 ?is volume1 & inde$ among ne>ly all great e>?quakes1 9 visit+ a region :]e seismic di/urbances 7 almo/ unkn[n4 ,calabria & ,is*ia1 ! ,rivi]a & ,&alusia1 ,assam & ! prov9ces ( ,m9o & ,ow>i 9 ,japan1 are all regions :]e e>?quake-%ocks are m or less frequ5t & occasionally ( de/ructive viol5ce4 ,b1 f ! f\ndation ( ,*>le/on 9 #afhj until #ahhf1 t is1 = m ?an two c5turies1 x is probably n too mu* to say t few c\nties 9 ,great ,brita9 7 s free f e>?quakes z ! ,/ate ( ,s\? ,c>ol9a4#ch ,! practical isolation ( ! e>?quake ( #ahhf left its trace on ! "* ( ! inve/igation4 ,n only 7 ! obs]v]s untra9$1 b ! inve/igators !mselves 7 unprep>$4 ,= in/ance1 ! scale ( int5sity us$ 9 draw+ ! isoseismal l9es 0 n adopt$ until aft] ! fir/ lett]s ( inquiry 7 issu$4 ,on ! o!r h&1 no?+ c\ld exce$ ! en]gy & ability ) :i* ! epic5tral tracts 7 exam9$ by ,mr4 ,e>le ,sloan & ! collection ( "t-records made by ,mr4 ,ev]ett ,hayd54 ,to !m1 & to ,major ,c4,e4 ,dutton1 ^: valuable monograph sup]s$es all o!r acc\nts1 we are indebt$ = ! two *ief additions to our k result+ f ! /udy ( ! ,*>le/on e>?quake4 ,^! are ! det]m9ation ( ! d\ble epic5tre1 & ! measurem5t ( ! velocity ) :i* ! e>?-waves travell$4 ,,damage ,,caus$ ,,by ,,! ,,e>?quake4 ,! l&-area di/urb$ by ! e>?quake & ! isoseismal l9es are %[n 9 ,fig4 #be1 ! small black oval area 7:i* ,includes ,*>le/on7 be+ t )9 :i* ! greate/ damage to build+s occurr$4 ,! *ief "p ( ! epic5tre1 h[ev]1 lies f #ab to #ae miles to ! we/ & nor?-we/ ( ,*>le/on1 9 a =e/-clad di/rict1 conta9+ only two villages & v>i\s scatt]$ h\ses4 ,! city ( ,*>le/on1 ^: population betwe5 #ahhj & #ahia increas$ f fifty to fifty-five ?\s&1 is built on a p59sula betwe5 ! ,coop] ,riv] on ! ea/ & ! ,a%ley ,riv] on ! s\?-we/4 ,orig9ally1 ?is 0 an irregul> tract ( comp>atively high & dry l&1 int]sect$ by num]\s creeks1 :i*1 z ! city grew1 7 fill$ up to ! g5]al level ( ! high] gr\nd4 ,x is on ?is made l& z a rule t ! m s]i\s damage to build+s occurr$4 ,at #i4ea ,p4,m4 7/&>d "t ( ! #ge? m]idian71 ! great e>?quake occurr$1 &1 "o m9ute lat]1 !re 0 left h>dly a build+ 9 ! city t 0 n injur$ m or less s]i\sly4 ,! de/ruction1 z ,major ,dutton rem>ks1 0 n ( t sweep+ & unmitigat$ ord] :i* has befall5 o!r cities1 & 9 :i* e /ructure built ( mat]ial o!r ?an wood has be5 levell$ completely to ! e>? 9 a *aos ( brok5 rubble1 beams1 tiles1 & plank+1 or left 9 a condition practically no bett]4 ,! numb] ( h\ses entirely demoli%$ 0 n great1 b sev]al hundr$ lo/ a l>ge "p ( _! walls1 & _m 7 condemn$ z unsafe & aft]w>ds pull$ d[n4 ,a bo>d ( inspectors1 appo9t$ to inve/igate ! condition ( ! h\ses1 report$ t n "o hundr$ out ( f\rte5 ?\s& *imneys exam9$ by !m escap$ damage1 & t #ie p] c5t4 ( ^? injur$ 7 brok5 (f at ! ro(4 ,! total co/ ( ! necess>y repairs1 x 0 e/imat$1 w\ld am\nt to ab\t "o million p\nds4 ,accord+ to ! (ficial records1 #bg p]sons 7 kill$ 9 ,*>le/on dur+ ! e>?quake1 b1 by cold1 exposure1 etc41 ?is numb] 0 br\ght up to n less ?an #hc4 ,! numb] ( p]sons w\nd$ 0 nev] asc]ta9$4 ,,isoseismal ,,l9es ,,& ,,di/urb$ ,,area4 ,9 draw+ ! isoseismal l9es 7repres5t$ by ! cont9u\s curves 9 ,fig4 #be71 ,major ,dutton made use ( ! well-kn[n ,rossi-,=el scale ( seismic int5sity1 a translation ( :i* is giv5 bel[4#ci ,! curves range f ! highe/ degree1 #aj1 correspond+ to disa/r\s effects on build+s1 d[n to ! l[e/ b "o1 #b1 :i* w\ld be appli$ to a %ock felt only by a small numb] ( p]sons at re/4 ,x is evid5t1 ,i ?9k1 t ^! l9es _c be reg>d$ z drawn ) great accuracy4 ,! numb] ( records 7ne>ly #djjj1 f ab\t #a1fjj places71 great z x is1 is h>dly suffici5t = ! purpose2 & _m 7 collect$ f newspap]s4 ,! circul>s ( inquiry also conta9$ no di/9ct que/ions correspond+ to ! diff]5t degrees ( ! scale employ$1 & !re=e x is n always c]ta9 t ! int5sity record$ 0 ! maximum obs]v$4 ,b1 if ! curves might h v>i$ 9 detail ) a l>g] & m accurate s]ies ( obs]vations1 !y mu/ repres5t 9 _! ma9 features ! di/ribution ( seismic int5sity ?r\gh\t ! di/urb$ area4 ,"o po9t ( importance is ! p>tial e>?quake-%ad[ 9 ! region ( ! ,appala*ian ,m\nta9s %[n by ! s\?w>d incurv+ ( ! isoseismals #d1 #e1 & #f1 & especially by ! fir/ two ( ^! l9es4 ,ano!r is ! close gr\p+ ( ! isoseismals 9 ! ,/ate ( ,mississippi1 illu/rat+ a rapid fad+ ( int5sity z ! e>?-waves cross$ ! unconsolidat$ mat]ials ( ! ,mississippi delta4 ,illu/ration3 ,,fig4 #be4--;,isoseismal l9es ( ,*>le/on e>?quake4 7,dutton1 etc47 ,ow+ to ! %ort di/ance betwe5 ! epic5tre & ! sea-coa/1 x is impossible to make m ?an a r\gh e/imate ( ! ext5t ( ! di/urb$ area4 ,ev5 :5 ! b\nd>y lies on l&1 x trav]ses "s di/ricts :i* are ?9ly populat$ & o!rs :]e ! inhabitants are unobs]vant1 & unlikely to notice ! sl[ oscillations :i* 7 alone p]ceptible at great di/ances4 ,! %ock 01 h[ev]1 felt at ,bo/on 7#hjj miles f ! epic5tre71 ,la ,crosse on ! upp] ,mississippi 7#iej miles to ! nor?-we/71 at sev]al places 9 ,cuba 7betwe5 #gjj & #gaj miles71 & 9 ,b]muda 7#iej miles74 ,to ! s\?1 ! limits are unkn[n1 !re be+ no report f ,yucatan1 ! ne>e/ po9t ( :i* is di/ant ab\t #icj miles4 ,if we assume ! di/urb$ area to h a mean radius ( #iej miles1 !n x mu/ h cov]$ no less ?an #b1hjj1jjj squ>e miles4 ,&1 t ?is e/imate is n excessive1 w be evid5t f ! fact t ! l&-area di/urb$ 7includ+ p>ts ( ! great lakes & inlets 9 ! sea-coa/7 am\nt$ to ab\t #ibj1jjj squ>e miles4 ,,prep>ation ,,= ,,! ,,e>?quake4 ,! prep>ation = ! e>?quake seems to h begun ab\t ?ree mon?s be=e4 ,dur+ ,june1 & ev5 e>li]1 slight b und\bt$ tremors are said to h be5 felt 9 ,*>le/on1 b no record ( !m 0 kept until ab\t #h ,a4,m4 on ,augu/ #bg?1 :5 a decid$ e>?quake occurr$ at ,summ]ville1 a village tw5ty-two miles to ! nor?-we/4 ,! %ock & s\nd 7 simultane\s1 ! %ock a s+le jolt or heavy j>1 ! s\nd l\d & sudd52 !y 7 su* z might h be5 caus$ by ! fir+ ( a heavy cannon or ! explosion ( a boil] or bla/ ( gunp[d]4 ,at #d4de ,a4,m4 on ,augu/ #bh?1 ! %ock & s\nd 7 repeat$1 only m /rongly1 ! =m] be+ di/9ctly felt z f> z ,*>le/on4 ,dur+ t day & ! next1 !re 7 sev]al o!r %ocks at ,summ]ville1 & !n re/ & quiet succe$$ until ! ev5+ ( ,augu/ #ca/4 ,,nature ,,( ,,! ,,%ock4 ,at #i4ea ,p4,m4 7to take "o ( ! be/ descriptions71 ! att5tion ( an obs]v] 9 ,*>le/on 0 vaguely attract$ by a s\nd t seem$ to come f ! (fice bel[1 & 0 suppos$ = a mom5t to be caus$ by ! rapid roll+ ( a heavy body1 z an iron safe or a heavily-lad5 truck1 ov] ! floor4 ,accompany+ ! s\nd !re 0 a p]ceptible tremor ( ! build+1 n m m>k$1 h[ev]1 ?an w\ld be caus$ by ! passage ( a c> or dray along ! /reet4 ,= p]haps two or ?ree seconds ! occurr5ce excit$ no surprise or comm5t4 ,!n by swift degrees1 or all at once--x is difficult to say :i*--! s\nd deep5$ 9 volume1 ! tremor became m decid$1 ! e> caught ! rattle ( w9d[-sa%es1 gas-fixtures1 & o!r movable objects2 ! m5 9 ! (fice 444 glanc$ hurri$ly at ea* o!r & sprang to _! feet4444 ,& !n all 0 bewild]m5t & confusion4 ,! long roll deep5$ & spread into an awful ro>1 t seem$ to p]vade at once ! tr\bl$ e>? & ! /ill air above & ar\nd4 ,! tremor 0 n[ a rude1 rapid quiv]1 t agitat$ ! :ole l(ty1 /rong-wall$ build+ z ?\gh x 7 be+ %ak5--%ak5 by ! h& ( an immeasurable p[]1 ) int5t to te> its jo9ts asund] & scatt] its /ones & bricks abroad4444 ,!re 0 no int]mission 9 ! vibration4444 ,f ! fir/ to ! la/ x 0 a cont9u\s j>1 add+ =ce ) e mom5t1 &1 z x approa*$ & rea*$ ! climax ( its manife/ation1 x seem$ = a few t]rible seconds t no "w ( human h&s c\ld possibly survive ! %ocks4 ,! floors 7 heav+ "u-foot1 ! surr\nd+ walls & p>titions visibly sway$ to & fro1 ! cra% ( fall+ masses ( /one & brick & mort> 0 he>d ov]head & )\t4444 ,= a second or two x seem$ t ! wor/ _h pass$1 & t ! viol5t motion 0 subsid+4 ,x increas$ aga9 & became z sev]e z be=e4 ,none expect$ to escape4 ,a sudd5 ru% 0 simultane\sly made to endeavor to atta9 ! op5-air & fly to a place ( safety2 b1 be=e ! door 0 rea*$ all /opp$ %ort1 z by a common impulse1 feel+ t hope 0 va9--t x 0 only a "q ( dea? )9 ! build+ or )\t1 ( be+ buri$ b5ea? ! s9k+ ro( or cru%$ by ! fall+ walls4 ,! upro> sl[ly di$ away 9 seem+ di/ance4 ,! e>? 0 /ill1 & oh6 ! bless$ relief ( t /illness4 ,if some:at s5sational 9 =m1 ?is report gives an extremely vivid & g5]ally accurate acc\nt ( ! great %ock4 ,o!r obs]v]s 9 ,*>le/on concur 9 divid+ ! movem5t into five phases4 ,! prelim9>y tremors & murmur+ s\nd la/$ ab\t twelve seconds1 &1 al?\gh !y increas$ 9 /r5g?1 !y 7 succe$$ some:at sudd5ly by ! viol5t oscillations ( ! second phase1 foll[$ by a ?ird phase ( mu* less int5sity & a f\r? ( /rong] oscillations1 ^! ?ree phases la/+ altoge!r ab\t fifty seconds4 ,! fif? phase1 9 :i* ! tremors di$ out r rapidly1 cont9u$ ab\t eight seconds2 s t ! total duration ( ! e>?quake 0 n less ?an sev5ty seconds4 ,! v>iation ( ! int5sity ) ! "t is repres5t$ r\ghly by ! curve 9 ,fig4 #bf4 ,illu/ration3 ,,fig4 #bf4--;,curve ( int5sity at ,*>le/on4 7,dutton47 ,at ,*>le/on1 !re 7 ?us two decid$ maxima ( int5sity1 ne>ly equal 9 /r5g?1 ?\gh ! fir/ seems to h be5 slightly m p[]ful ?an ! second4 ,z 9 ! ,&alusian e>?quake1 ! int]v5+ tremors 7 imp]ceptible at a di/ance f ! epic5tre1 & ! e>?quake appe>$ 9 ! =m ( two di/9ct %ocks1 sep>at$ by an int]val ! av]age duration ( :i* 0 e/imat$ at slightly less ?an half a m9ute4 ,at mo/ places1 ! fir/ %ock is describ$ z ! /rong]1 b ! diff]5ce 9 int5sity ( ! two p>ts c\ld n h be5 great1 = bo? 7 notic$ at sev]al places m ?an #fjj miles f ! epic5tre4 ,visible ,e>?-,waves4--,_m p]sons 9 ! meizoseismal area ass]t t !y saw waves mov+ along ! surface ( ! gr\nd4 ,at ,*>le/on1 accord+ to an obs]v] :o 0 fac+ a /reet-lamp at ! "t1 ! progress ( ! waves z !y pass$ ! h\se1 go+ t[>ds ! s\?-ea/1 0 pla9ly obs]v$1 al?\gh !y travell$ ) incomp>able swiftness4 ,! %ad[ ( ea* mov+ ridge ca/ f ! gas-light 0 di/9ctly se54 ,! waves 7 n 9 long roll]s1 b _h r ! appe>ance ( 'gr\nd-swells' 9 deep wat]1 ! height ( :i* f cre/ to tr\gh he e/imat$ at n less ?an two feet4 ,9 ! words ( ano!r obs]v]1 ,! vibrations increas$ rapidly & ! gr\nd began to undulate l ! sea4 ,! /reet 0 well light$1 hav+ ?ree gas-lamps )9 a di/ance ( #bjj feet1 & ,i c\ld see ! e>? waves z !y pass$ z di/9ctly z ,i h a ?\s& times se5 ! waves roll along ,sullivan's ,isl& bea*4 ,! fir/ wave came f ! s\?-we/1 & z ,i attempt$ to make my way 444 ,i 0 borne irresi/ibly across f ! s\? side to ! nor? side ( ! /reet4 ,! waves seem$ !n to come f bo? ! s\?-we/ & nor?-we/1 & cross$ ! /reet diagonally1 int]sect+ ea* o!r1 & lift+ me up & lett+ me d[n z if ,i 7 /&+ on a *op sea4 ,i c\ld see p]fectly1 & made c>eful obs]vations1 & ,i e/imate t ! waves 7 at lea/ two feet 9 height4 ,,! ,,d\ble ,,epic5tre4 ,= seismological purposes1 x is un=tunate t ! epic5tral di/rict %\ld be "o conta9+ s few build+s & o!r objects t c\ld pres]ve ! effects ( ! %ock4 ,x is = ! mo/ "p a b>r51 =e/-clad region1 9 places swampy1 ) occasional scatt]$ h\ses4 ,b x is cross$ by ?ree l9es ( railway div]g+ f ,*>le/on1 & ! damage :i* !y suff]$ supplem5ts to "s ext5t ! defects aris+ f ! sc>city ( build+s4 ,^! railway l9es are ! ,s\? ,c>ol9a1 ! ,nor?-,ea/]n1 & ! ,*>le/on & ,savannah1 d5ot$ by ! lett]s ,a1 ,b1 & ,c1 respectively1 9 ,figs4 #bh & #bi4dj ,x w be conv5i5t to foll[ ,major ,dutton1 & trace ! v>iation ( int5sity exhibit$ along ea* l9e4 ,= six miles along ! ,s\? ,c>ol9a ,railway 7,a7 ! damage to ! l9e1 ?\gh indicative ( a /rong %ock1 0 ( little consequ5ce4 ,9 ! fir/ half ( ?is di/ance no repairs 7 requir$1 b at #c-b_/c miles ! rails 7 b5t & ! jo9ts betwe5 !m op5$2 at #e miles1 ! fi%-plates 7 torn f _! fa/5+s & ! jo9ts betwe5 ! rails op5$ sev5 in*es2 & at ne>ly #f miles ! jo9ts 7 aga9 op5$1 & ! road-b$ depress$ six in*es4 ,aft] ?is po9t1 deflections ( ! l9e & elevations & depressions ( ! road-b$ 7 no long] r>e4 ,ne> ! #i-mile po9t1 ! int5sity ( ! %ock seem$ to increase mo/ rapidly2 lat]al displacem5ts ( ! l9e became m frequ5t z well z great] 9 am\nt4 ,! di/ortions ( ! l9es 7 probably greate/ betwe5 #aj & #aa miles2 "h !y 7 (t5 displac$ lat]ally1 sometimes depress$ or elevat$1 & occasionally twi/$ into ,s-%ap$ curves1 :ile _m hundr$ y>ds ( ! track 7 %ov$ bodily t[>ds ! s\?-ea/4 ,! buckl+ always took place :5 ?is lat]al %ov+ enc\nt]$ a rigid ob/acle1 usually a long rigid tre/le4 ,at ! nor?-we/]n end ( ! tre/le ! accumulation ( rails result$ 9 a %>p k9k4 ,correspond+ ext5sions ( ! track by ! op5+ ( ! jo9ts & %e>+ ( ! fi%-plate bolts occurr$ "s di/ance to ! nor?-we/w>d4 ,at #aa-a_/b miles1 ! l9es 7 aga9 /ret*$ & ! jo9ts op5$ by ab\t sev5 in*es2 b1 f ?is po9t = m ?an f\r miles1 ! %>p k9ks reveal+ a slid+ ( ! track 7 entirely abs5t1 ?\gh !re 7 /ill long slight flexures 9 ! l9es & *anges ( level 9 ! road-b$4 ,! railway 9 ?is section trav]ses a di/rict :i* is p>tly a swamp & p>tly a rice-field2 & ?us x may be1 z ,major ,dutton sugge/s1 t ! gr\nd 0 less fitt$ to pres]ve ! effects ( ! %ock4#da ,at ab\t #ah miles1 ! l9e rea*es high] & firm] gr\nd2 &1 f "h to ,summ]ville 7#ba-b_/c miles71 !re 7 _m s9u\s flexures4 ,= six miles f>!r1 viol5t di/ortions ( ! rails ceas$ to occur1 ! rate ( decrease 9 int5sity be+ mo/ m>k$ ne> ! #bc-mile po9t4 ,! la/ flexure occurr$ at ,j$burgh 7#bg-a_/b miles7 at ! s\? end ( a long1 heavy tre/le 7,fig4 #bg74 ,illu/ration3 ,,fig4 #bg4--;,flexure ( rails at ,j$burgh4 7,dutton47 ,!re is ?us a c]ta9 symmetry 9 ! damage to ?is l9e ) respect to a po9t ab\t #ae or #af miles f ! ,*>le/on t]m9us4 ,! *anges ( int5sity are mo/ rapid at di/ances ( ab\t #i & #bc miles f ! t]m9us4 ,also1 on ! s\?-ea/ side ( ! #af-mile po9t1 ! longitud9al displacem5ts ( ! l9e are always to ! s\?-ea/2 on ! o!r side1 always to ! nor?-we/4 ,major ,dutton !re=e inf]s t ! epic5tre mu/ be on a l9e drawn ne>ly ?r\gh ! #af-mile po9t at "r angles to ! railway4 ,some:at simil> *anges 7 not$ along ! ,nor?-,ea/]n ,railway 7,b71 ! ,*>le/on t]m9us ( :i* is ab\t ?ree-qu>t]s ( a mile to ! s\?-ea/ ( t ( ! ,s\? ,c>ol9a ,railway4 ,slight flexures 9 ! l9e occurr$ at di/ances ( #a-a_/b & #d miles f ! t]m9us1 & at ab\t #f miles ! road-b$ 0 depress$1 9 "o "p by z mu* z #bb in*es4 ,at ab\t #f-a_/c miles1 ! jo9ts betwe5 ! rails 7 op5$ #ad in*es1 & !re 7 slight s9u\s flexures 9 ! l9e ne> ! #g-mile & #h-mile po9ts4 ,! indications ( great int5sity !n rapidly increas$1 ! rate ( *ange be+ greate/ ne> ! #i-mile po9t4 ,"h1 !re 0 a long lat]al flexure ) a %ift ( #d in*es ea/w>d4 ,half-a-mile f>!r1 ! fi%-plates 7 brok5 & ! rails p>t$ #h-a_/b in*es4 ,a little beyond ! #aj-mile po9t1 an embankm5t #ae feet high 0 pu%$ #d-a_/b feet ea/w>d along a *ord ( #aej feet4 ,at ! #ab-mile po9t & beyond1 fi%-plates 7 brok51 l9es 7 b5t & ! jo9ts op5$2 ! road-b$ 0 cut by a s]ies ( cracks1 "o ( :i* 0 #ba in*es wide1 :ile ! beg9n+ ( a long tre/le 0 %ift$ #h-a_/c feet to ! we/4 ,f #ab-a_/b to #ad-a_/b miles1 sev]al build+s 7 damag$ or de/roy$ by a movem5t :i* 0 cle>ly m v]tical ?an horizontal4 ,ne> ! #af-mile po9t1 ! gr\nd 0 fissur$ & ?r[n into ridges1 ! rails be+ simil>ly b5t 9 a v]tical plane4 ,soon aft] ?is1 ! l9e rea*es a broad1 s&y tract1 &1 ?\gh ! ?ickness ( ! s& is probably n mu* m ?an #dj feet 9 any place1 ! di/urbances dim9i% almo/ at once1 &1 = a di/ance ( m ?an two miles1 !re 0 little damage done to ! l9e4 ,at ,m\nt ,holly ,/ation 7#ah miles71 ! int5sity 0 s slight t ! h\ses suff]$ no injury m s]i\s ?an ! loss ( *imneys4 ,half-a-mile f>!r1 ! gr\nd becomes less s&y1 & ! effects ( ! %ock m di/9ct4 ,! l9es 7 b5t 9 places = ab\t a qu>t] ( a mile1 aft] :i* !y aga9 pass into ! s&y area ) a decrease ( damage1 ! la/ flexure be+ ne> ! #ba-mile po9t4 ,! rate ( *ange ( int5sity 9 ?is "p ( ! l9e appe>s to h be5 greate/ at a di/ance ( ab\t #ai-a_/b miles f ! t]m9us1 b ! exact di/ance is obvi\sly some:at unc]ta94 ,!re is aga9 a r\gh symmetry 9 ! damage to ! l9e1 ! c5tral po9t be+ ab\t #ad miles f ! ,*>le/on t]m9us4 ,a l9e drawn ?r\gh ?is po9t at "r angles to ! ,nor?-,ea/]n ,railway 7or r to t "p ( x betwe5 ! #i-mile & #ai-a_/b-mile po9ts7 %\ld pass ?r\gh ! epic5tre4 ,x meets ! correspond+ l9e = ! ,s\? ,c>ol9a ,railway 9 a po9t :i* is indicat$ 9 ,figs4 #bg & #bh by a small circle 7,w74 ,h\ses & o!r build+s are r>e 9 ! surr\nd+ di/rict2 b1 z ! int5sity ( ! %ock dim9i%$ outw>ds 9 all directions1 ?is po9t mu/ m>k approximately ! position ( ! epic5tre4 ,z x is close to ! ,wood/ock ,/ation on ! ,s\? ,c>ol9a ,railway1 x is call$ by ,major ,dutton ! ,wood/ock epic5tre4 ,! ,*>le/on & ,savannah ,railway 7,c7 uses ! same l9es z ! ,nor?-,ea/]n = ! fir/ sev5 miles f ,*>le/on1 & !n turns (f 9 a s\?-we/]ly direction4 ,= #d-a_/b miles f ! junction ! signs ( di/urbance 7 few & unimportant4 ,! railway !n crosses ! ,a%ley ,riv]1 ! banks ( :i* slid t[>ds "o ano!r & jamm$ ! drawbridge2 b = f\r miles f>!r !re 0 no s]i\s damage done to ! l9es4 ,at ab\t #af-a_/b miles ! effects ( ! %ock became rapidly m app>5t4 ,= ne>ly #a-a_/b mile ! entire railroad 0 deflect$ into an irregul> curve1 ! displacem5t be+ greate/ at ! bridge1 :]e x crosses ! ,/ono ,riv]4 ,"h1 x 0 z mu* z #cg in*es to ! s\?4 ,aft] ,rant[les ,/ation 7#ah miles71 !re 7 _m displacem5ts1 bo? lat]al & v]tical4 ,at #ah-a_/b miles1 a long s\?w>d deflection began1 ! am\nt ( :i* rea*$ #be in*es at ! #ai-mile po9t1 #ej in*es half-a-mile f>!r on1 & 0 /ill great] at #bj-b_/c miles4 ,= two miles m1 s9u\s flexures 7 cont9u\s1 b1 at ! #bb-b_/c-mile po9t1 !y rapidly disappe>$1 ! railroad pass+ on to high] & firm] gr\nd4 ,betwe5 #be & #bg miles1 !re 7 occasional slight flexures 9 ! l9e or depressions ( ! railroad2 b1 aft] ! #bg-a_/d-mile po9t1 !y seldom occur1 &1 :5 !y d1 are ( little consequ5ce4 ,"s ( ! effects describ$ 9 ! la/ p>agraph may1 z ,major ,dutton sugge/s1 be due to ! v>y+ nature ( ! surface-rocks4 ,x is important to notice1 h[ev]1 t di/urbances ( ! l9es 7 exce$+ly r>e 9 ! section t lies ne>e/ to ! ,wood/ock epic5tre1 & t !y increase 9 viol5ce = "s di/ance f t region1 ! maximum int5sity be+ rea*$ a mile or two to ! we/ ( ,rant[les ,/ation4 ,?is po9ts cle>ly to ! exi/5ce ( a second focus4 ,un=tunately1 !re are v few h\ses or o!r objects 9 ! neighb\rhood1 & ! position ( ! correspond+ epic5tre _c be det]m9$ accurately4 ,major ,dutton places x 9 ! position indicat$ by a small circle 7,r71 & calls x ! ,rant[les epic5tre f its vic9ity to ! /ation ( t "n4 ,if ! meizoseismal area _h be5 a ?ickly populat$ "o1 ! evid5ce ( ru9$ & damag$ h\ses w\ld h provid$ mat]ials = ! con/ruction ( isoseismal l9es surr\nd+ ! two epic5tres4 ,x is difficult1 z x is1 to gauge ! equality ( ! effects on objects s diff]5t z railway-l9es & build+s2 & ! isoseismals %[n 9 ,figs4 #bh & #bi c !re=e lay no claim to accuracy4 ,fig4 #bh %[s ! epic5tral isoseismals z !y are drawn by ,mr4 ,e>le ,sloan4 ,!y d n correspond to ! degrees ( any def9ite scale ( seismic int5sity2 b !y may be tak5 z repres5t+ ! impressions ( a v c>eful obs]v]1 :o trav]s$ ! di/rict imm$iately aft] ! occurr5ce ( ! e>?quake1 & :o1 :5 draw+ ^! l9es1 0 biass$ by no preconceiv$ !ory4 ,major ,dutton1 rely+ *iefly on ,mr4 ,sloan's writt5 notes1 int]prets ! evid5ce diff]5tly1 & obta9s ! s]ies ( curves %[n 9 ,fig4 #bi4 ,9 ?is case1 also1 ! isoseismals correspond to no express$ /&>d ( int5sity4 ,!y are int5d$ m]ely to repres5t ! =ms ( ! curves1 &1 by _! less or great] di/ance ap>t1 ! m or less rapid rate at :i* ! int5sity v>i$4 ,! *ief diff]5ce betwe5 ! two maps conc]ns ! =m ( ! ,wood/ock isoseismals4 ,major ,dutton draws !m approximately circul>1 leav+ ! map blank t[>ds ! nor?1 :]e h>dly any evid5ce 0 =?com+4 ,mr4 ,sloan attributes ! scant9ess ( effects "h to a dim9ution ( int5sity1 & makes ! l9es curve 9 t[>ds ! epic5tre4 ,!y c]ta9ly mu/ d s 9 cross+ ! ,nor?-,ea/]n ,railway2 & ! some:at s\!rly tr5d ( ,mr4 ,sloan's curves to ! ea/ ( ?is railway seems to me to furni% ! bett] repres5tation ( ! di/9ctly great] int5sity 9 t region4 ,illu/ration3 ,,fig4 #bh4--;,epic5tral isoseismal l9es ( ,*>le/on e>?quake accord+ to ,mr4 ,sloan4 7,dutton47 ,illu/ration3 ,,fig4 #bi4--;,epic5tral isoseismal l9es ( ,*>le/on e>?quake accord+ to ,major ,dutton4 7,dutton47 ,m important1 h[ev]1 ?an ?is div]g5ce ( op9ion is ! agreem5t 9 "o respect betwe5 ! two sets ( curves4 ,bo? %[ a m>k$ expansion ar\nd ! po9ts kn[n z ! ,wood/ock & ,rant[les epic5tres1 especially ab\t ! =m]1 & a contraction 9 ! int]m$iate region4 ,! evid5ce ( ^! isoseismals !re=e confirms t ( ! damag$ railway l9es1 & e/abli%es ,major ,dutton's inf]5ce t !re 7 two di/9ct foci1 ! epic5tres ( :i* 7 ab\t ?irte5 miles ap>t4 ,,orig9 ,,( ,,! ,,d\ble ,,%ock4 ,9 ! la/ *apt]1 x 0 %[n t ! d\ble %ock ( ! ,&alusian e>?quake c\ld be due only to two di/9ct impulses tak+ place ei!r )9 ! same focus or1 m probably1 9 two deta*$ foci4 ,simil> reason+ applies to ! ,*>le/on e>?quake4 ,! d\ble maximum or d\ble %ock 0 obs]v$ 9 no less ?an f\rte5 ,/ates4 ,moreov]1 ! int]val betwe5 ! two maxima at ,*>le/on appe>s f ,fig4 #bf to h be5 ab\t #cd seconds 9 l5g?4 ,?us1 ! duplication ( ! %ock _c h be5 a m]ely local ph5om5on1 nor c x h result$ f ! sep>ation into two p>ts ( ! e>?-waves proce$+ f a s+le di/urbance4 ,ea* maximum mu/ !re=e be connect$ ) a di/9ct impulse4 ,comb9+ ?is inf]5ce ) ,major ,dutton's discov]y ( ! d\ble focus1 no d\bt c rema9 z to ! orig9 ( ! repeat$ %ock4 ,x is cle>1 also1 t ! impulse at ! ,wood/ock focus 0 ! /rong] ( ! two2 = ! isoseismals spread out m widely r\nd ! correspond+ epic5tre1 & !re 0 no rapid decl9e ( int5sity f t po9t1 su* z might be associat$ ) a weak] di/urbance )9 a %all[ focus4 ,illu/ration3 ,,fig4 #cj4--,planes ( oscillation ( /opp$ p5dulum clocks at ,*>le/on4 ,aga91 s9ce ! e>li] "p ( ! %ock is almo/ uni=mly describ$ z ! /rong]1 x foll[s t ! ,wood/ock focus 0 ! fir/ 9 action4 ,a curi\s fact record$ by ,major ,dutton supports ?is inf]5ce4 ,9 ,*>le/on1 f\r clocks 7 /opp$ by ! %ock1 ! errors ( :i* at ! "t 7 c]ta9ly less ?an eight or n9e seconds4 ,! planes 9 :i* _! p5dulums oscillat$ are %[n by ! l9es lett]$ ,a1 ,b1 ,c1 & ,d 9 ,fig4 #cj1 ! brok5 l9es ,w & ,r repres5t+ respectively ! directions f ,*>le/on ( ! ,wood/ock & ,rant[les epic5tres4 ,clock ,a /opp$ at #i;h4 #eam4 #js41 ,b at #i;h4 #eam4 #aes41 ,c at #i;h4 #eam4 #afs41 & ,d 7:i* _h be5 reset to ! second e>li] 9 ! day7 at #i;h4 #eam4 #dhs4 ,n[1 if ! plane ( oscillation co9cid$ ne>ly ) ! direction ( ! %ock1 ! only effect w\ld be a tempor>y *ange 9 ! p]iod ( oscillation2 b if x 0 at "r angles to ! direction ( ! %ock1 ! clock might be /opp$ by ! po9t ( ! p5dulum cat*+ beh9d ! graduat$ arc 9 front ( :i* x oscillat$4 ,! planes ( ! fir/ ?ree clocks1 x w be se51 7 approximately at "r angles to ! direction ( ! ,wood/ock epic5tre1 & ,b & ,c 7 inde$ /opp$ 9 ! mann] j describ$2 :ile ! plane ( %ock ,d 0 ne>ly p]p5dicul> to ! direction ( ! ,rant[les epic5tre4 ,z ! p5dulums ( ,b & ,c might make a few /agg]+ oscillations be=e _! f9al arre/1 ,major ,dutton assigns #i;h4 #eam4 #abs4 z ! epo* ( ! fir/ maximum at ,*>le/on2 &1 z ! int]val betwe5 ! two maxima 0 ab\t #cd seconds1 ?is w\ld give ab\t #i;h4 #eam4 #dfs4 = ! epo* ( ! second maximum--a "t :i* agrees v closely ) t giv5 by clock ,d4 ,?us1 clocks ,a1 ,b1 & ,c mu/ h be5 /opp$ by ! ,wood/ock vibrations1 & clock ,d ab\t half-a-m9ute lat] by ^? com+ f ! ,rant[les focus4 ,,dep? ,,( ,,! ,,seismic ,,foci4 ,two me?ods ( e/imat+ ! dep? ( ! seismic focus h be5 describ$ 9 ! prec$+ pages--namely1 ,mallet's1 dep5d+ on ! angle ( em]g5ce1 & ,falb's1 bas$ on ! int]val betwe5 ! initial epo*s ( ! s\nd & %ock4 ,to ^!1 ,major ,dutton adds a ?ird me?od1 9 :i* he relies on ! rate at :i* ! int5sity ( ! %ock v>ies ) ! di/ance f ! epic5tre4 ,dutton's ,me?od ( det]m9+ ! ,dep? ( ! ,focus4--,if ! seismic focus is ei!r a po9t or a sph]e1 & ! initial impulse equal 9 all directions1 & if ! int5sity ( ! %ock dim9i%es inv]sely z ! squ>e ( ! di/ance f ! focus1 !n ! cont9u\s curve 9 ,fig4 #ca w repres5t ! v>iation ( int5sity along a l9e pass+ ?r\gh ! epic5tre ,e4 ,! =m ( ! curve on ^! assumptions does n dep5d 9 any way on ! initial int5sity ( ! impulse2 x is gov]n$ solely by ! dep? ( ! focus4 ,! deep] ! focus1 ! flatt] becomes ! curve1 z we h se5 9 discuss+ ! ,is*ian e>?quakes 7p4 #fh74 ,9 all directions f ! epic5tre1 ! int5sity at fir/ dim9i%es sl[ly2 b ! rate ( *ange ( int5sity ) ! di/ance soon becomes m rapid1 until x is a maximum at ! po9ts ,c1 ,c2 aft] :i* x aga9 dim9i%es & dies out v sl[ly :5 ! di/ance becomes great4 ,x w be evid5t f ,fig4 #ah t ! deep] ! focus ! great] also is ! di/ance ,,ec ( ! po9ts :]e ! int5sity ( ! %ock *anges mo/ rapidly4 ,x may be easily %[n1 inde$1 t ?is di/ance always be>s to ! dep? ( ! focus ! con/ant ratio ( #a to sqrt7#c71 or ab\t #a to #a4gc4db ,n[1 if a s]ies ( isoseismals c\ld be drawn correspond+ to int5sities :i* diff] by con/ant am\nts1 we %\ld h a s]ies ( circles l ^? surr\nd+ ! ,wood/ock epic5tre 9 ,fig4 #bi1 ! di/ance betwe5 successive l9es at fir/ decreas+ gradually until x is a m9imum at ! dott$ circle & aft]w>ds gradually increas+4 ,?is dott$ circle is obvi\sly t :i* passes ?r\gh all po9ts :]e ! int5sity ( ! %ock *anges mo/ rapidly4 ,major ,dutton calls x ! index-circle &1 :5 its radius is kn[n1 ! dep? ( ! focus is at once obta9$ by multiply+ ! radius by #a4gc4 ,9 #aheh1 ,mallet propos$ a me?od :i* be>s "s resemblance to ! above1#dc b dep5d+ only on ! int5sity ( ! longitud9al waves4 ,major ,dutton claims = 8 me?od t ! effects ( ! longitud9al & transv]se waves are n sep>at$1 t x takes acc\nt ( ! total en]gy irrespective ( direction or k9d ( vibration4 ,illu/ration3 ,,fig4 #ca4--;,diagram to illu/rate ,dutton's me?od ( det]m9+ dep? ( seismic focus4 ,objections to ,dutton's ,me?od4--,i h describ$ ?is me?od some:at fully1 ?\gh x seems to me op5 to m s]i\s objections ?an ,mallet's fir/ me?od :i* x is int5d$ to replace4 ,we h1 9 ! fir/ place1 no reason = suppos+ t ! focus is ei!r a po9t or a sph]e1 or t ! initial impulse is uni=m 9 all directions4 ,if ! e>?quake 7 caus$ by fault-slipp+1 bo? assumptions w\ld be untrue1 & x is = ^? :o employ ! me?od to prove _! validity4 ,b ( great] consequ5ce is ! fact t1 if ! me?od 7 correct1 all e>?quakes orig9at+ at ! same dep? mu/ h index-circles ( equal radii4 ,if ! dep? ( ! focus 71 say1 t5 miles1 !n ! index-circle mu/ h a radius ( ab\t six miles1 :e!r ! initial di/urbance be ( extreme viol5ce or s weak t x is n felt at ! surface at all1 mu* less s f> z six miles f ! epic5tre4 ,! law ( ! inv]se squ>e is ( c\rse only true = a p]fectly ela/ic & cont9u\s m$ium1 & ! real curve ( int5sity is n t ( ! cont9u\s l9e 9 ,fig4 #ca1 b some?+ ( ! =m repres5t$ by ! dott$ l9e4 ,9 ?is case1 ! rate ( *ange ( int5sity is greate/ at "s po9t ,c'1 ne>] ?an ,c to ! epic5tre1 & ! application ( ,major ,dutton's rule w\ld give a po9t ,f'1 ne>] ! surface ?an ,f1 = ! focus4 ,?us1 assum+ t ! me?od c be appli$ 9 practice--& ! te/ involv$ is "o s delicate t x w\ld be difficult to apply except ) ref9$ measurem5ts--!n all t we c ass]t is t ! calculat$ dep? is c]ta9ly less ?an ! true dep?4 ,dutton's ,e/imate ( ! ,dep? ( ! ,seismic ,foci4--,9 apply+ ! me?od1 ! *ief difficulty is to obta9 a s]ies ( isoseismal l9es correspond+ to equidi/ant degrees ( int5sity4 ,z already po9t$ out1 ^? giv5 9 ,fig4 #bi are m]ely diagrammatic2 b ! index-circle ( ! ,wood/ock focus1 repres5t$ by ! dott$ l9e1 is made to pass ?r\gh ! places :]e ! rate ( *ange ( int5sity 0 f\nd to be greate/4 ,! radius ( ?is circle be+ v ne>ly sev5 miles1 x foll[s t ! result+ dep? ( ! ,wood/ock focal po9t w\ld be ab\t twelve miles4 ,major ,dutton reg>ds ?is e/imate z probably correct )9 two miles4 ,9 ! neighb\rhood ( ! ,rant[les epic5tre1 ! isoseismals 9 bo? ,figs4 #bh & #bi are elongat$ 9 =m4 ,! index-circuit1 z x w\ld be call$ 9 su* a case1 _c be drawn completely1 b its radius p>allel to ! %ort] axis ( ! curves is ab\t #d-a_/b miles1 & ! result+ dep? ( ! ,rant[les focal po9t w\ld be ne>ly eight miles4 ,,velocity ,,( ,,! ,,e>?-,,waves4 ,! recognition ( ! d\ble epic5tre is1 f a geological po9t ( view1 ! mo/ important fact e/abli%$ by ! inve/igation ( ! ,*>le/on e>?quake4 ,b ( equal int]e/1 f a physical po9t ( view1 is ! e/imate ( ! velocity ( ! e>?-waves1 :i* is probably m accurate ?an t det]m9$ = any previ\s %ock4 ,ow+ to ! exi/5ce ( ! /&>d "t sy/em 9 ! ,unit$ ,/ates1 ! exact "t is transmitt$ once a day to e t[n & village )9 rea* ( a telegraph l9e2 & ! effect ( small errors 9 ! obs]vations is consid]ably less5$ by ! great di/ance trav]s$ by ! e>?-waves1 sixty good reports com+ f places m ?an #ejj miles f ! epic5tre1 & t5 f places m ?an #hjj miles di/ant4 ,! total numb] ( "t-records collect$ is #caf1 b ( ^! #acj _h to be reject$1 ei!r because !y 7 obvi\sly too e>ly or too late1 or because !y 7 only giv5 to ! ne>e/ five-m9utes' int]val4 ,!re rema9 #ahf obs]vations :i* are divid$ by ,major ,dutton into f\r classes accord+ to _! probable value4 ,9 an e>?quake ( su* great duration 7ab\t #gj seconds at ,*>le/on71 x is necess>y 9 ! fir/ place to select "s special phase ( ! movem5t z t to :i* ! records ma9ly ref]1 & !n to det]m9e z accurately z possible ! "t ( occurr5ce ( ?is phase at ! orig94 ,!re c be little d\bt z to :i* phase %\ld be *os54 ,! %ock began ) a s]ies ( tremors1 :i* pass$ some:at abruptly into ! oscillations t =m$ ! fir/ & /rong] maximum4 ,^! 7 cle>ly felt all ov] ! di/urb$ area1 &1 z ! beg9n+ ( ! fir/ maximum at places ne> ! epic5tre & ! beg9n+ ( ! %ock at di/ant /ations 7 probably due to ! same vibrations1 ?is p>ticul> phase may be fairly select$ z t to :i* ! "t-measurem5ts ref]4 ,! "t ( ?is phase at ! orig9 c only be asc]ta9$ f ! "t at :i* x rea*$ ,*>le/on1 & our k ( ?is dep5ds *iefly on ! evid5ce ( /opp$ clocks4 ,h[ unreliable ?is may be is well kn[n4 ,clocks may inde$ be /opp$ at almo/ any phase ( ! movem5t2 &1 :5ev] /opp$ clocks c be comp>$ ) really good p]sonal obs]vations1 !y almo/ inv>iably %[ a lat] "t4 ,at ,*>le/on ?ree good clocks 7 /opp$ by ! vibrations f ! ,wood/ock focus1 two ( !m be+ 9 close agreem5t 7p4 #aba72 &1 all[+ = a few oscillations be=e _! f9al arre/1 ,major ,dutton places ! "t ( arrival ( ! select$ phase at ,*>le/on at #i;h4 #eam4 #abs4 ,p4,m4 ,! evid5ce ( ^! clocks is also support$ by t ( o!r obs]vations1 :i* %[ t #i4ea 0 c]ta9ly ! ne>e/ m9ute to ! "t ( arrival1 & fav\r a some:at lat] in/ant mu* m /rongly ?an "o a little e>li]4 ,n[1 ! di/ance ( ,*>le/on f ! ,wood/ock epic5tre is sixte5 miles1 & f ! correspond+ focus 7) ! calculat$ value ( its dep?7 tw5ty miles4 ,a fir/ e/imate ( ! velocity gives a value ( a little m ?an ?ree miles a second1 & ! "t at ! ,wood/ock focus may !re=e be tak5 z #i;h4 #eam4 #fs4 ) a probable error ( a few seconds4#dd ,proce$+ to ! obs]vations at a di/ance1 we f9d !m1 ev5 aft] all rejections1 to be v diff]5t 9 value4 ,!y 7 !re=e divid$ into gr\ps consi/+ ( obs]vations :i* are z ne>ly z possible homog5e\s4 ,! fir/ gr\p conta9s five records f places betwe5 #deb & #fde miles f ! ,wood/ock epic5tre4 ,!y give ! "t to )9 #ae seconds1 obta9$ f an accurately kept clock1 or f a clock or wat* t 0 comp>$ ) su* )9 a few h\rs ( ! e>?quake4 ,! result+ velocity is #c4bcf plus or m9us 4#aje miles 7or #ebje plus or m9us #afh met]s7 p] second4#de ,9 ! second gr\p !re are elev5 obs]vations 7betwe5 di/ances ( #dch & #ggj miles7 :i* satisfy ! same conditions z ^? 9 ! fir/ gr\p1 except t ! "t is only giv5 to ! ne>e/ m9ute or half-m9ute4 ,! velocity obta9$ f !m is #c4bbf plus or m9us 4#adg miles 7or #eaib plus or m9us #bcf metres7 p] second4 ,! ?ird gr\p includ$ all b ! above records & ^? obta9$ f /opp$ clocks4 ,!y are #abe 9 numb] 7betwe5 di/ances ( #hj & #ibd miles71 b x is unc]ta9 :e!r !y correspond to ! select$ phase ( ! movem5t1 & ! errors ( ! clocks & wat*es us$ 7 unkn[n4 ,!y give a mean velocity ( #c4jac plus or m9us 4#jbg miles 7or #dhdh plus or m9us #dc metres7 p] second4 ,9 ! f\r? gr\p1 we h ! evid5ce ( #de /opp$ clocks 7at places betwe5 #bj & #hee miles71 :i* app>5tly give a velocity ( #b4fch plus or m9us 4#aje miles 7or #dbde plus or m9us 4#afh metres7 p] second4 ,at six places1 h[ev]1 ! times indicat$ by /opp$ clocks c be comp>$ ) good p]sonal obs]vations2 & ^! %[ t ! "t ( trav]se f ! orig9 obta9$ f ! =m] is on an av]age #a4bh times ! "t ( trav]se obta9$ f ! latt]4 ,if a simil> correction be made = all ! /opp$ clocks1 ! correct$ velocity ( ! e>?-waves w\ld be f #c4ag to #c4bc miles 7or #eajj to #ebjj metres7 p] second4 ,9 obta9+ ! mean value ( ! velocity f all ! obs]vations1 ^? ( ! f\r? gr\p are omitt$1 & ! weights ( ! fir/ ?ree gr\ps are tak5 inv]sely z ! squ>es ( ! probable errors--t is1 z #b3 #a3 #d4 ,! result+ mean velocity is #c4bba plus or m9us 4#jej miles 7or #eahd plus or m9us #hj metres7 p] second2 &1 ?\gh x does n foll[ t all o!r e/imates are errone\s 7= ! velocity may v>y ) ! /r5g? ( ! e>?quake & ) o!r conditions71 x is probable t ?is result is m ne>ly accurate ?an any o!r previ\sly obta9$4 ,,miscellane\s ,,ph5om5a4 ,fissures & ,s&-,crat]s4--,9 po9t ( size1 !re 0 no?+ rem>kable ab\t ! fissures 9 ! gr\nd produc$ by ! ,*>le/on e>?quake4 ,! l>ge/ 7 only a few hundr$ y>ds long1 &1 except ne> ! riv]-banks1 !y r>ely exce$$ an in* 9 wid?4 ,!y seem1 h[ev]1 to h be5 unusually abundant2 =1 )9 an area ( ne>ly #fjj squ>e miles surr\nd+ ! two epic5tres1 !y 7 almo/ univ]sal1 & ov] a mu* wid] area !y /ill occurr$ 9 great numb]s1 ?\gh ) some:at less cont9uity4 ,f _m ( ^! fissures wat] 0 eject$1 c>ry+ ) x l>ge quantities ( s& & silt1 & s abundantly t e /ream-b$1 ev5 ?\gh g5]ally dry 9 summ]1 0 flood$4 ,by ! passage ( ! wat]1 "s "p ( ! fissures 0 (t5 enl>g$ into a r\nd hole ( consid]able size1 end+ 9 a crat]let at ! surface4 ,c]ta9 belts )9 ! fissur$ area conta9$ l>ge numb]s ( ^! crat]lets1 ( all sizes up to tw5ty feet or m 9 diamet]4 ,"o ne> ,t5-,mile ,hill 0 tw5ty-"o feet across4 ,9 ?is di/rict1 !y 7 app>5tly l>g] & m num]\s ?an else:]e2 _m acres ( gr\nd be+ cov]$ ) s&1 :i*1 close to ! orifices1 0 two feet or m 9 dep?4 ,"h & !re1 ! wat] 0 eject$ ) consid]able viol5ce1 z 0 manife/ f ! heights to :i* x spurt$4 ,! te/imony ( witnesses on ?is po9t is ( c\rse d\btful1 = ! e>?quake occurr$ aft] nightfall1 b 9 a few places ! bran*es & leaves ( trees ov]hang+ ! orifices 7 smir*$ ) s& & mud up to a height ( fifte5 or tw5ty feet4 ,effects on ,human ,be+s4--,x is int]e/+ to notice ! behavi\r ( diff]5t races "u ! influ5ce ( a viol5t e>?quake1 & p]haps no great] contra/ c\ld be obs]v$ ?an betwe5 ! calmness exhibit$ by ! ,japanese 9 ! pres5ce ( disa/] & ! wild fe> m]g+ into helpless panic t *>act]is$ ! resid5ts1 & especially ! negroes1 ( ,*>le/on4 ,z we da%$ d[n ! /airway1 says a writ] already quot$ 7p4 #ajh71 & out into ! /reet1 f e qu>t] arose ! %rieks1 ! cries ( pa9 & fe>1 ! pray]s & wail+s ( t]rifi$ wom5 & *ildr51 comm+l$ ) ! ho>se %\ts ( excit$ m54444 ,on e side 7 hurry+ =ms ( m5 & wom51 b>ehead$1 p>tially dress$1 "s almo/ nude1 & all ne>ly craz$ ) fe> & excitem5t4444 ,a few /eps away1 "u ! gas-lamp1 a woman lies prone & motionless on ! pavem5t1 ) upturn$ face & out/ret*$ limbs1 & ! cr[d :i* has n[ ga!r$ 9 ! /reet passes h] by1 none paus+ to see :e!r %e is alive or dead 444 no "o kn[s :i* way to turn1 or :]e to (f] aid2 _m voices are speak+ at once1 b few he$ :at is said4 ,betwe5 ! selfi% ru% = safety "h describ$ & ! calm int]e/ ( ! mo/ di/ant obs]v]s1 ,major ,dutton records ne>ly e possible v>iety ( m5tal effects1 ! actions result+ f :i* may be r\ghly classifi$ z foll[s3 ,a4 ,no p]sons leave _! rooms4 ,b4 ,"s p]sons leave _! h\ses4 ,c4 ,mo/ p]sons run into ! /reets1 :i* are full ( excit$ p4 ,d4 ,p ru% wildly = op5 spaces & rema9 all night out-(-doors4 ,9 ! map ( ! isoseismal l9es 7,fig4 #be71 ! dott$ curves b\nd ! areas 9 :i* ! effects correspond+ to ! ?ree highe/ degrees ( ! above scale 7 obs]v$4 ,! curve = ! fir/ degree 7,a7 co9cides ( c\rse ) ! isoseismal l9e ( int5sity #b4 ,x w be se5 t !re is a c]ta9 r\gh correspond5ce betwe5 ^! curves & ! isoseismal l9es4 ,! curve ,d & ! isoseismal #h are close toge!r2 9 o!r words1 p ?\ght x wis] to camp out-(-doors = ! night if ! %ock 0 /rong en\gh to damage build+s slightly4 ,! curve ,c & ! isoseismal #f are simil>ly connect$2 t is1 if ! movem5t made pictures sw+1 etc41 p ru%$ into ! /reets4 ,on ! :ole1 ! curve ,b & ! isoseismal #c r\ghly co9cide1 or1 if ! %ock 0 n /rong en\gh to make doors & w9d[s rattle1 "s p]sons left _! h\ses & public meet+s 7 disp]s$4 ,feel+ ( ,nausea4--,a feel+ ( nausea 0 exp]i5c$ by _m p]sons at ! "t ( ! e>?quake1 some:at r>ely x appe>s 9 ! neighb\rhood ( ! epic5tre & ev5 outside ! isoseismal #g1 b m frequ5tly beyond ^! limits1 & p]ceptible z f> z ! brok5 l9e 9 ,fig4 #be4 ,! mo/ di/ant places at :i* x 0 notic$ are ,blue ,m\nta9 ,creek 7,new ,york7 & ,dubuque 7,i[a71 :i* are respectively #hbc & #hhf miles f ,*>le/on4 ,,aft]-,,%ocks4 ,z ,summ]ville lies six miles to ! nor?-we/ ( ! ,wood/ock epic5tre & ,*>le/on #af miles to ! s\?-ea/1 x is probable t _m ( ! aft]-%ocks 7 unfelt & a /ill great] numb] unrecord$4 ,9 ,*>le/on1 sev5 %ocks1 all mu* slight] ?an ! pr9cipal %ock1 7 felt dur+ ! night ( ,augu/ #ca--,septemb] #a1 & ?irty be=e ! end ( ,septemb]4 ,( ^!1 ! %ock ( ,septemb] #crd1 at #aa ,p4,m41 0 ! /ronge/1 b ^? :i* occurr$ on ,septemb] #a/1 #bnd1 #ba/1 & #bg? 7 also describ$ z sev]e1 & ! rema9d] z mod]ate or slight4 ,= weeks aft] ! great %ock1 curi\s s5sations 7 di/9ctly p]ceptible dur+ ! /ill h\rs ( ! night z ?\gh ! cru/ ( ! e>? 7 re/+ on a gelat9\s mass 9 con/ant motion4 ,! la/ %ock felt 9 ,*>le/on seems to h be5 "o record$ on ,m>* #ah?1 #ahhg4 ,at ,summ]ville1 _m %ocks occurr$ t 7 sc>cely p]ceptible 9 ,*>le/on1 & ^? notic$ 9 bo? places 7 usually /rong]1 & ! motion m ne>ly v]tical1 at ,summ]ville4 ,! peculi> *>act]i/ic ( all ( !m 0 ! deep1 solemn1 p[]ful boom1 l ! report ( a heavy cannon1 usually accompani$ by a quick1 %ort j>4 ,sometimes x 0 prolong$ into a heavy ro> or rumble1 z if _m reports 7 deliv]$ 9 a volley4 ,! numb] ( !m 0 nev] record$4 ,on ,septemb] #crd1 ,mr4 ,w4,j4 ,mc,gee1 ( ! ,unit$ ,/ates ,geological ,survey1 arriv$ at ,summ]ville4 ,dur+ ! ev5+ ( t day1 detonations 7 he>d at int]vals1 av]ag+ p]haps half-an-h\r1 accompani$ occasionally by v slight spasmodic tremors ( an in/ant's duration4 ,!y 7 mu* l peals ( ?und] at a di/ance ( half-a-mile or m1 ?\gh r m muffl$4 ,x 0 my impression1 ,mr4 ,mc,gee rem>ks1 t ! s\nd 0 sometimes ab\t z grave z ! e> c p]ceive1 resembl+ some:at ! tremul\s ro> sometimes accompany+ combu/ion 9 locomotives4 ,^! s\nds cont9u$1 b ) dim9i%+ frequ5cy1 ?r\gh\t ! rema9d] ( ! ye> & z late z ,july #a/1 #ahhg4 ,,orig9 ,,( ,,! ,,e>?quake4 ,major ,dutton's valuable monograph is a record ( ! e>?quake-ph5om5a4 ,he (f]s no !ory z to ! cause ( ! %ock1 & is !re=e 9 no way responsible = ! acc\nt giv5 9 ! rema9+ "p ( ?is *apt]4 ,t !re 7 two seismic foci he has %[n1 ,i ?9k1 conclusively2 & my object is n[ to trace out briefly ! probable nature ( ! movem5ts t produc$ ! d\ble %ock4 ,ref]r+ to ,figs4 #bh & #bi1 x w be se5 t1 accord+ to bo? ,mr4 ,sloan & ,major ,dutton1 ! isoseismals surr\nd+ ! ,rant[les epic5tre are di/ort$ along a l9e :i* runs f a few degrees ea/ ( nor? to a few degrees we/ ( s\?4 ,_! oval =m is 9 all probability connect$ ) a focus elongat$ 9 ab\t ! same direction4 ,ne> ! ,wood/ock epic5tre1 ! isoseismals are drawn diff]5tly 9 ! two maps1 & 9 nei!r case d !y (f] any sure guide z to ! =m ( ! seismic focus4 ,if1 h[ev]1 we foll[ ,mr4 ,sloan's int]pretation ( ! evid5ce1 & suppose ! e>?quake to h be5 fault-=m$1 !n x is probable t 9 ?is region ! fault b5ds r\nd slightly t[>ds ! ea/4 ,! only o!r evid5ce on ?is po9t is t af=d$ by ! regions ( defective int5sity1 real or app>5t1 along ! ?ree railway-l9es div]g+ f ,*>le/on4 ,"o ( ^! occurr$ ne> ,m\nt ,holly ,/ation on ! ,nor?-,ea/]n ,railway 7,b1 ,figs4 #bh & #bi71 ano!r = f\r miles />t+ f ! #aa-a_/b-mile po9t on ! ,s\? ,c>ol9a ,railway 7,a71 & a ?ird along ! ,*>le/on & ,savannah ,railway 7,c7 ov] a di/ance ( f\r miles f ! ,a%ley ,riv]4 ,9 ! fir/ two cases1 ,major ,dutton sugge/s t ! less am\nt ( damage 0 due to ! nature ( ! soil trav]s$ by ! railway2 b x is on ! s(t] gr\nd t ! effects ( an e>?quake-%ock are g5]ally ! m disa/r\s4 ,on ! :ole1 x seems to me probable t ! ?ree tracts ref]r$ to are really regions ( less int5sity1 & x is wor?y ( notice t !y lie along a ne>ly /raight l9e4 ,to %[ ! be>+ ( ^! rem>ks1 let ,,cd 7,fig4 #cb7 repres5t ! section ( a fault & ,,ef t ( ! surface ( ! e>?1 & suppose ! rock-mass ,a to slip slightly & sudd5ly d[nw>ds4 ,!n ! p>ticles ( ,a at ! surface ( ! fault w1 by impulsive friction1 be drawn %>ply upw>ds1 & ^? ( ,b correspond+ly d[nw>ds2 s t ! e>?-waves 9 ! two rock-masses w />t 9 opposite phases ( vibration4 ,along ! l9e ( fault1 e p>ticle ( rock1 be+ urg$ upw>ds & d[nw>ds almo/ equally1 w rema9 practically at re/4 ,?us1 regions ( defective int5sity may arise f p>tial int]f]5ce by ! spread+ ( ei!r e>?-wave 9 ! adjo9+ rock-mass4 ,illu/ration3 ,,fig4 #cb4--;,diagram to expla9 orig9 ( regions ( defective int5sity4 ,if ?is be ! correct explanation1 ! pa? ( ! orig9at+ fault may be tak5 z t indicat$ by ! brok5 l9e 9 ,fig4 #bh1 a l9e :i* is ne>ly p>allel to ! *ief bran*es ( ! isoseismal curves4#df ,z bo? epic5tres lie on ! we/ side ( ?is l9e1 ! fault mu/ hade or slope 9 ?is direction4 ,! di/ortion ( ! ,wood/ock isoseismals t[>ds ! nor?-we/ confirms ! latt] inf]5ce1 = ! int5sity ( ! %ock is great] on ! side t[>ds :i* ! fault hades4 ,f ! comp>ative abs5ce ( e>?quakes 9 ,s\? ,c>ol9a1 we may inf] t ! fault is "o subject to displacem5ts at wide int]vals ( "t4 ,! gradually increas+ /ress along its surface 0 reliev$ at "o or two po9ts 9 or ne> ! ,wood/ock focus on ,augu/ #bg? & #bh?1 & p]haps dur+ ! prec$+ mon?s4 ,b ! fir/ great slip took place sudd5ly 9 t focus1 & spread gradually s\?w>ds--= !re 0 no int]ruption 9 ! movem5t--until ab\t half-a-m9ute lat] x rea*$ ! ,rant[les focus1 :]e ! second great slip occurr$4 ,eight or t5 m9utes aft]w>ds !re 0 ano!r slip--9 :at "p ( ! fault is unc]ta9--& ?is 0 foll[$ at irregul> int]vals by _m small movem5ts gradually dim9i%+ 9 frequ5cy & 9 focal area4 ,)9 a ye> f ! fir/ di/urbance1 ! fault-sy/em atta9$ once m its usual condition ( re/4 ,,ref]5ces4 #a4 ,,dutton1 ,c4,e4--,! ,*>le/on ,e>?quake ( ,augu/ #ca/1 #ahhf4 ,am]4 ,geol4 ,survey1 ,n9? ,annual ,report1 pp4 #bji-ebh4 #b4 ,nature1 vol4 xxxv41 #ahhg1 pp4 #ca-cc2 vol4 lxiii41 #aija1 pp4 #afe-aff4 ,,footnotes3 #ch ,! au?orities = ?is /atem5t are ,mallet's ,catalogue ( ,record$ ,e>?quakes 7,brit4 ,assoc4 ,rep41 #aheb1 pp4 #a-agf2 #ahec1 pp4 #aag-bab2 #ahed1 pp4 #a-cbf71 :i* closes ) ! ye> #ahdb1 & ,fu*s' ,/ati/ik d] ,erdbeb5 von #ahfe-ahhe4 ,accord+ to ,mallet1 !re 0 an e>?quake 9 ,s4 ,c>ol9a 9 ,novemb] #aggf1 & ! ,new ,madrid e>?quake ( ,decemb] #af?1 #ahaa1 0 felt at ,*>le/on4 ,fu*s records two e>?quakes at ,*>le/on on ,may #ab?1 #ahgj1 & ,decemb] #ab?1 #ahgf2 & two 9 ,s4 ,c>ol9a on ,decemb] #ab? & #ac?1 #ahgi4 #ci #a4 ,record$ by a s+le seismograph1 or by "s seismographs ( ! same patt]n1 b n by sev]al seismographs ( diff]5t k9ds1 ! %ock felt by an exp]i5c$ obs]v]4 #b4 ,record$ by seismographs ( diff]5t k9ds2 felt by a small numb] ( p]sons at re/4 #c4 ,felt by sev]al p]sons at re/2 /rong en\gh = ! duration or direction to be appreciable4 #d4 ,felt by sev]al p]sons 9 motion2 di/urbance ( movable objects1 doors1 w9d[s2 creak+ ( floors4 #e4 ,felt g5]ally by e "o2 di/urbance ( furniture & b$s2 r++ ( "s bells4 #f4 ,g5]al awak+ ( ^? asleep2 g5]al r++ ( bells2 oscillation ( *&eli]s1 /opp+ ( clocks2 visible di/urbance ( trees & %rubs2 "s />tl$ p]sons leave _! dwell+s4 #g4 ,ov]?r[ ( movable objects1 fall ( pla/]1 r++ ( *ur* bells1 g5]al panic1 )\t damage to build+s4 #h4 ,fall ( *imneys1 cracks 9 ! walls ( build+s4 #i4 ,p>tial or total de/ruction ( "s build+s4 #aj4 ,great disa/]s1 ru9s1 di/urbance ( /rata1 fissures 9 ! e>?'s cru/1 rock-falls f m\nta9s4 #dj ,9 ord] to simplify ^! figures1 ! riv]s1 mo/ ( ! inlets1 & o!r details are omitt$4 ,small figures are add$ along ! railway l9es to d5ote ! di/ance 9 miles f ! /ations 9 ,*>le/on4 #da ,if ?is 7 s1 ! decrease 9 int5sity w\ld be only app>5t2 b x may h be5 real1 & a possible explanation on ?is supposition is giv5 lat] on 7p4 #ace74 #db ,if c be ! dep? ( ! focus1 a ! int5sity at unit di/ance f ! focus1 & y ! int5sity on ! surface at di/ance x f ! epic5tre1 !n ya_/7c#bx#b7 ,! incl9ation ( ! curve at any po9t is giv5 by dy_/dx-#b99;a99x_/7c#bx#b7b1 & ?is is a maximum :5 d#by_/dx#b or 7#c99x#b-;c#b7_/7;c#bx#b7c is z]o1 :i* is satisfi$ :5 cx99sqrt7#c7 #dc ,briti% ,association ,report1 #aheh1 pp4 #aja-ajc4 #dd ,! above "t w\ld h to be increas$ by "o second if ! dep? ( ! focus 7 v small1 & dim9i%$ by "o second if x 7 z great z #bc miles2 ! diff]5ce 9 ei!r case be+ less ?an ! probable error4 #de ,! me?od employ$ is z foll[s3 ,let t#j be ! comput$ "t 7#i;h4 #eam4 #fs47 at ! focus1 x seconds ! error 9 ?is e/imate1 t ! report$ "t at a giv5 place1 ,d its di/ance f ! focus 9 miles1 & y ! numb] ( seconds requir$ to travel "o mile2 !n1 assum+ t y does n v>y ) ! di/ance1 we h x,dytt#j4 ,an equation ( ?is =m is obta9$ f ea* obs]vation1 & ! me?od ( lea/ squ>es is !n appli$ to det]m9e ! mo/ probable values ( x & y4 #df ,?is seems to me ! m probable c\rse4 ,x is possible1 h[ev]1 t ! fault-l9e may pass f ,m\nt ,holly ,/ation to ! ea/ ( ! ,wood/ock epic5tre z %[n 9 ,fig4 #bh1 & !n to ! we/ ( ! ,rant[les epic5tre1 ! fault *ang+ its direction ( hade 9 ! int]m$iate di/rict4 ,,*apt] ,,vi4 ,,! ,,rivi]a ,,e>?quake ,,( ,,febru>y #bc,,rd1 #ahhg4 ,few e>?quakes h ar\s$ a m widespread int]e/ ?an ^? :i* /ruck ! ?rong$ cities ( ! ,rivi]a on ,febru>y #bcrd1 #ahhg4 ,! fir/ & greate/ ( ! %ocks occurr$ at ab\t #f4bj ,a4,m41 ! second n9e m9utes lat]1 & ! ?ird1 int]m$iate 9 /r5g?1 at ab\t #h4ea ,a4,m4#dg ,all ?ree %ocks 7 ( de/ructive viol5ce1 ! damage wr\ght by !m ext5d+ along ! coa/ & = a %ort di/ance inl& f ,nice to beyond ,savona4 ,mo/ ( ! injury to prop]ty & ne>ly all ! loss ( life 71 h[ev]1 conc5trat$ on ! ea/]n side ( ! fronti]2 & x !re=e fell to ! lot ( ! ,italian ,gov]nm5t to provide = ! sci5tific inve/igation ( ! e>?quakes1 z well z to meet ! wants ( ^? depriv$ ( home & support4 ,pr(essors ,t>amelli & ,m]calli1 :o two ye>s be=e _h /udi$ ! e>?quakes 9 ,&alusia1 7 aga9 nom9at$1 ! =m] to exam9e ! geology ( ! c5tral regions1 & ! latt] to report on ! seismic ph5om5a4 ,_! jo9t memoir =ms "o ( ! mo/ complete acc\nts t we possess ( any e>?quake1 & is ! *ief au?ority = ! description giv5 9 ?is *apt]4 ,ano!r valuable monograph is t prep>$ by ,pr(essor ,a4 ,issel1 ( ,g5oa1 :o receiv$ an indep5d5t appo9tm5t f ! same ,m9i/ry4 ,a ?ird (ficial commission 0 also s5t to e/imate ! am\nt ( damage caus$ by ! e>?quakes 9 ! ,italian t[ns & villages4 ,9 ,france1 ! de/ruction ( prop]ty 0 mu* less s]i\s1 & att5tion 0 conf9$ *iefly to ! records ( ! %ock provid$ by magnetographs & o!r in/rum5ts 9 di/ant obs]vatories4 ,9 ,switz]l&1 ! effects rem>k$ 7 m]ely ^? due to ! evanesc5t vibrations ( a remote e>?quake2 b _m int]e/+ records 7 collect$ by ! p]man5t seismological commission e/abli%$ 9 t c\ntry4 ,,damage ,,caus$ ,,by ,,! ,,e>?quakes4 ,ow+ to v>iations 9 ! nature1 f\ndation1 & site ( build+s1 !re is always great div]sity 9 ! de/ructive effects ( an e>?quake4 ,9 "o & ! same t[n1 mo/ ( ! h\ses may be raz$ to ! gr\nd1 :ile 9 _! mid/ may be f\nd "s t are %att]$ b /ill /&+1 & o!rs p]haps t are practically unh>m$4 ,! /rong] aft]-%ocks (t5 complete ! ru9 ( ! p>tially damag$ h\ses2 ?\gh 9 su* cases ! real loss is z a rule comp>atively small4 ,! close succession ( ! two /rong aft]-%ocks ( ,febru>y #bcrd made x impossible z a rule to sep>ate _! effects f ^? due to ! fir/ %ock2 b x has be5 r\ghly e/imat$ t ab\t "o-qu>t] ( ! total damage 0 caus$ by ! two aft]-%ocks toge!r4 ,to !m also mu/ be ref]r$ 9 "p ! comp>atively small numb] ( w\nd$1 _m p]sons buri$ b5ea? ! ru9s hav+ no d\bt p]i%$ f subsequ5t falls be=e !y c\ld be extricat$4 ,tak+ all ?ree %ocks toge!r1 ! total loss to prop]ty1 accord+ to ,pr(essor ,m]calli1 mu/ be valu$ at ab\t #bb million francs 9 ,italy alone4 ,= ! prov9ce ( ! ,alpes ,m>itimes 9 ,france1 full details are want+1 b ! loss !re _c fall f> %ort ( ?ree million francs4 ,! total am\nt ( damage mu/ !re=e be plac$ at ab\t a million p\nds4 ,f ! figures giv5 by ! (ficial commissions1 x appe>s t ! e>?quakes 7 mo/ disa/r\s at ,diano ,m>9a & ,diano ,ca/ello2 :ile o!r places1 su* z ,oneglia1 ,bussana1 ,bai>do1 ,pompeiana1 & ,vallecrosia1 suff]$ only a little less sev]ely4 ,at ,m5tone ab\t #aee h\ses1 & at ,nice ab\t #fa h\ses1 7 r5d]$ un9habitable1 & _m o!rs 7 badly injur$4 ,9 ,italy1 #fcc p]sons 7 kill$1 #dcb s]i\sly w\nd$1 & #ajd slightly w\nd$2 9 ,france1 #g p]sons 7 kill$ & #cj s]i\sly w\nd$1 ! numb] ( p]sons slightly w\nd$ be+ unkn[n4 ,! majority ( ! dea?s occurr$ 9 two or ?ree places4 ,?us1 at ,diano ,m>9a1 #aij p]sons 7 kill$ & #ajb w\nd$2 at ,bai>do1 #bbj 7 kill$ & #fj w\nd$2 at ,bussana1 !re 7 #ec kill$ & #bg w\nd$4 ,! dea?-rates 71 h[ev]1 comp>atively small1 am\nt+ = ! above places to n m ?an #h-a_/b1 #ad1 & #f-a_/b p] c5t41 respectively2 figures :i* only slightly exce$ ^? obta9$ = places 9 ! meizoseismal area ( ! ,&alusian e>?quake4 ,?\gh ! damage c h>dly be reg>d$ z excessive1 x 0 nev]!less l>gely due to ! peculi> ar*itecture preval5t 9 ! ,rivi]a4 ,ar*es 9 ! walls are common ev5 9 ! upp] /oreys1 &1 9 ,oneglia & ,diano ,m>9a1 if n also 9 o!r places1 ! floors are ne>ly always brick ar*es abutt+ aga9/ ! walls & )\t o!r lat]al support4 ,pr(essor ,m]calli believes t1 9 private h\ses1 m ?an #ij p] c5t4 ( ! dead bodies 7 cru%$ b5ea? ^! fall5 ar*es4 ,! height ( ! build+s is also great 9 proportion to ! f\ndation & to ! ?ickness ( ! walls2 & ! ma9 walls are int]rupt$ by num]\s ap]tures1 f ! corn]s ( :i* ne>ly all ! fissures sprang4 ,9 "s ( ! coa/ t[ns1 ! h\ses are built ( r\nd$ /ones ga!r$ f ! bea*1 or ( rubble ) /ones ( all %apes & sizes1 b\nd by cem5t ( ! poore/ quality4 ,la/ly1 z mu* ( ! damage due to previ\s e>?quakes _h be5 badly repair$1 x is evid5t t ! de/ructiv5ess ( ! ,rivi]a e>?quakes mu/ to a great ext5t be ref]r$ to prev5table causes4 ,! occurr5ce ( ! pr9cipal %ock %ortly aft] six on ! morn+ ( ,a% ,w$nesday mu/ also h increas$ ! dea?-rate2 = _m p]sons1 aft] a night ( amusem5t1 _h la9 d[n = a %ort "t & 7 sleep+ heavily2 :ile o!rs _h already ris5 & 7 collect$ 9 ! *ur*es2 ! circum/ances 9 ei!r case r5d]+ escape m difficult4 ,tak+ acc\nt1 h[ev]1 ( ?is accid5tal increase 9 ! numb] ( victims1 ,pr(essor ,m]calli consid]s t ! e>?quake ( #ahhg 0 ! mo/ disa/r\s ( all ^? :i* h visit$ ei!r ! ,rivi]a or nor!rn ,italy 9 ! la/ ?ree c5turies2 ?\gh1 dur+ ! n9ete5? c5tury1 !re 7 ?ree ,italian e>?quakes ( f> great] de/ructive p[]1 b all conf9$ to ! s\!rn "p ( ! p59sula--namely1 ! ,neapolitan e>?quakes ( #ahje & #aheg1 & ! ,is*ian e>?quake ( #ahhc4 ,,prep>ation ,,= ,,! ,,e>?quakes4 ,x is difficult1 z usual1 to specify ! exact mom5t :5 ! fir/ e>?quake ( ! #ahhg s]ies took place2 b x is evid5t t ! prep>ation = ! great %ock 0 v brief4 ,at ,oneglia1 x is alleg$ t fa9t %ocks & s\nds 7 obs]v$ _m times1 *iefly at night1 dur+ ! mon? prec$+ ,febru>y #bcrd2 ?\gh !y 7 n at ! "t suppos$ to be ( seismic orig94 ,a slight %ock is also report$ f ,diano at ab\t midnight on ,febru>y #ba-bb4 ,! fir/ und\bt$ %ock occurr$ on ,febru>y #bbnd1 at ab\t #h4cj ,p4,m41 or t5 h\rs be=e ! pr9cipal e>?quake4 ,?\gh v slight1 x 0 felt ?r\gh\t ! ,rivi]a & 9 "p ( ,pi$mont4 ,ano!r %ock1 also weak1 took place at ab\t #aa ,p4,m42 & a ?ird1 s5sible only 9 ! ea/]n "p ( ! ,ligurian ,ap5n9es1 on ,febru>y #bcrd1 at ab\t #a ,a4,m42 at :i* "t ! tide-gauge at ,g5oa record$ "s abnormal oscillations4 ,an h\r lat]1 a m important1 ?\gh by no means a /rong1 %ock occurr$2 ?is 0 p]ceptible all ov] ! ,rivi]a1 9 ,pi$mont1 & 9 ,corsica2 9 o!r words1 x di/urb$ a region agree+ closely ) ! c5tral area ( ! disa/r\s %ock4 ,at ab\t #e ,a4,m41 a fif? %ock1 some:at weak] ?an ! prec$+1 0 felt ov] ! same area1 concurr5tly1 or ne>ly s1 ) ano!r abnormal oscillation ( ! tide-gauge at ,g5oa2 :ile a six? %ock 0 notic$ at sev]al places a few m9utes be=e ! great %ock4 ,dur+ ! night ( ,febru>y #bb-bc1 n]v\s p]sons 9 _m t[ns & villages 7 agitat$ )\t app>5t reason4 ,birds & animals1 m s5sitive ?an human be+s to fa9t tremors1 7 m di/9ctly affect$1 especially = "s m9utes be=e ! e>?quake4 ,horses refus$ food1 7 re/less or tri$ to escape f _! /ables1 dogs h[l$1 birds flew ab\t & utt]$ cries ( al>m4 ,z ^! symptoms 7 notic$ at m ?an "o hundr$ & ?irty places )9 ! ,italian "p ( ! c5tral area1 !re c be little d\bt t !y 7 caus$ by microseismic movem5ts = ! mo/ "p ins5sible to man4 ,,isoseismal ,,l9es ,,& ,,di/urb$ ,,area4 ,! only complete map ( ! isoseismal l9es is t drawn by ,pr(essor ,m]calli4#dh ,9 ?is map1 reproduc$ 9 ,fig4 #cc1 ! cont9u\s curves repres5t ! pr9cipal isoseismal l9es2 ! dott$ curves def9e ! di/urb$ areas ( two ( ! /rong] aft]-%ocks4 ,! meizoseismal area1 b\nd$ by ! curve m>k$ #a 9 ,fig4 #cc1 is also %[n on a l>g] scale 9 ,fig4 #cd4 ,at ! places d5ot$ by small circles 9 ! latt] figure1 ! pr9cipal %ock 0 disa/r\s1 "s ( ! h\ses 9 ea* be+ ei!r totally or p>tially ru9$4 ,at ^? m>k$ by a small cross1 ! %ock 0 almo/ ru9\s2 9 o!r words1 num]\s h\ses 7 damag$1 b 9 no case 0 ! injury ( a s]i\s "*4 ,! meizoseismal area is ?us a n>r[ b&1 skirt+ ! ,rivi]a coa/ f ,m5tone to ,albissola1 a di/ance ( #ajf miles1 & ext5d+ inl& = n m ?an f n9e to twelve miles4 ,! greate/ int5sity1 correspond+ to ! ru9 ( _m h\ses ) consid]able loss ( life1 0 rea*$ at only a few places betwe5 ,bussano & ,diano ,m>9a1 all ly+ )9 a littoral b& ab\t tw5ty miles 9 l5g? & ?ree to ?ree & a half miles 9 wid?4 ,if1 h[ev]1 ! epic5tre _h la9 on l&1 ! area w\ld h be5 mu* great]1 ,pr(essor ,m]calli e/imates ab\t f\r times great]1 ?an its actual am\nt4 ,illu/ration3 ,,fig4 #cc4--;,isoseismal l9es ( ! ,rivi]a e>?quake4 7,m]calli47 ,! curve m>k$ #b 7,fig4 #cc7 b\nds ! almo/ ru9\s zone2 its expansion t[>ds ! nor? & contraction t[>ds ! we/1 nor?-we/1 & ea/1 be+ its mo/ notewor?y features4 ,! next zone1 t ( slight damage1 is conta9$ betwe5 ! isoseismals #b & #c1 ! latt] curve probably graz+ ! nor? end ( ,corsica4 ,beyond ?is lies ! /rong zone1 9 :i* ! %ock 0 g5]ally felt )\t caus+ any damage to build+s4 ,its b\nd>y 7m>k$ #d7 passes ne> ,m>seilles1 ,como1 & ,p>ma1 & includes ne>ly ! :ole ( ,corsica2 t[>ds ! nor?-we/1 9 ! valley ( ,ao/a1 x curves 9 t[>ds ! isoseismal #c4 ,9 ! out]mo/ zone ( all ! %ock 0 slight1 & t[>ds ! m>g9 0 only j p]ceptible4 ,! b\nd>y1 :i* ( c\rse def9es t ( ! di/urb$ area1 rea*es z f> nor? z ,basle & ,dijon1 to ,p]pignan on ! we/1 ,tr5to1 ,v5ice1 & ,pord5one on ! ea/1 & to ! s\? z f> z ,tivoli 7ne> ,rome7 & ! nor!rn end ( ,s>d9ia4 ,9 ea/]n ,switz]l&1 x %[s a m>k$ curve inw>ds2 possibly1 z ,pr(essor ,m]calli sugge/s1 f ! vibrations hav+ to cross ! nor!rn ,ap5n9es 9 a direction ne>ly at "r angles to _! axis4 ,except = ?is bay1 h[ev]1 ! curve diff]s little f a circle1 ! c5tre ( :i* lies 9 ! sea1 a little to ! s\? ( ,oneglia1 close to ! position assign$ by o!r evid5ce to ! epic5tre4 ,! radius ( ?is circle be+ ab\t #bfd miles1 x foll[s t ! di/urb$ area mu/ h conta9$ ab\t #bai1jjj squ>e miles--by no means a l>ge am\nt = s /rong an e>?quake4 ,,position ,,( ,,! ,,epic5tres4 ,x is evid5t1 f ! =m ( ! meizoseismal area %[n 9 ,fig4 #cc1 t a m]e fr+e ( x lies ^u l&1 & t ! epic5tre mu/ be situat$ "s di/ance out at sea4 ,o!r facts may be m5tion$ :i* po9t to ! same conclusion4 ,!re 71 = in/ance1 no purely v]tical movem5ts obs]v$1 ev5 9 ! di/ricts :]e ! damage done by ! %ock 0 greate/4 ,nor 7 any l>ge l&slips to be se5 9 ^? areas2 !re 7 no la/+ *anges 9 ! und]gr\nd wat]-sy/em2 & 9 g5]al1 z ,pr(essor ,m]calli rem>ks1 all ! sup]ficial di/ortions ( ! gr\nd :i* are s *>act]i/ic ( ! epic5tral area ( a great e>?quake 7 conspicu\s by _! abs5ce4 ,!re is evid5ce1 aga91 ( "s di/urbance ( ! sea-b$ 9 ! dea? & flight ( fi%es f great dep?s & 9 ! seismic sea-waves record$ by ! tide-gauges at ,g5oa & ,nice4 ,^! ph5om5a w be describ$ 9 a lat] section1 b ref]5ce %\ld be made "h to an int]e/+ obs]vation at ,oneglia on ! occurr5ce ( "s ( ! /rong] aft]-%ocks4 ,p]sons on ! coa/1 x is said1 saw ! sea curl+ & mov+1 & imm$iately aft]w>ds ! %ock 0 felt4 ,9 det]m9+ ! position ( ! epic5tre1 ,pr(essor ,m]calli _h rec\rse z usual to obs]vations on ! direction ( ! %ock1 especially ^? d]iv$ f ! oscillation ( lamps or o!r susp5d$ objects1 ! projection or fall ( bodies free to move1 fractures1 etc41 9 damag$ h\ses1 & ! /opp+ ( p5dulum clocks4 ,su* obs]vations 7 made at #abj places--#gb 9 ! we/]n ,rivi]a & ! ,alpes ,m>itimes1 & #dh at ,pi$mont1 ,lomb>dy1 & ,tuscany4 ,at _m ( ^! places ! movem5t 0 extremely complicat$4 ,9 ne>ly all p>ts ( ! area mo/ /rongly %ak51 = in/ance1 ! direction ( ! %ock *ang$ m ?an once2 & x 0 !re=e necess>y to select :5ev] possible ! pr9cipal direction ( ! %ock at ea* place4 ,9 "s t[ns1 su* z ,oneglia1 ,m5tone1 ,antibes1 ,cuneo1 etc41 ! %ock _h two dom9ant directions1 & ^! appe>$ to be s5sibly at "r angles to "o ano!r2 an incl9ation :i*1 z ,pr(essor ,m]calli sugge/s1 may be due 9 "p to ! approximation ( ! real directions to ^? ( ! pr9cipal walls ( ! h\ses 9 :i* ! obs]vations 7 made4 ,mo/ ( ! l9es ( direction1 :5 plott$ on ! map1 conv]ge t[>ds an area ly+ betwe5 ! m]idians ( ,oneglia & ,san ,remo1 & betwe5 n9e & fifte5 miles f ! coa/4 ,= places ne> ! epic5tre1 ! mo/ tru/wor?y1 9 ,m]calli's op9ion1 are ^? made at ,oneglia1 ,m5tone1 ,taggia1 ,bordigh]a1 ,ca/el ,vittorio1 ,nice1 & ,g5oa2 & ! po9ts 9 :i* ^! l9es ,int]sect "o ano!r are ,indicat$ by small crosses on ! map ( ! meizoseismal area 7,fig4 #cd74 ,all ( !m lie at sea at di/ances betwe5 six & fifte5 miles to ! s\? ( ,oneglia4 ,! mo/ probable position ( ! pr9cipal epic5tre is t m>k$ by ! small circle ,a1 :i* is situat$ ab\t fifte5 miles s\? ( ,oneglia4 ,illu/ration3 ,,fig4 #cd4--,meizoseismal area ( ! ,rivi]a e>?quake4 7,t>amelli & ,m]calli47 ,!re are1 h[ev]1 sev]al l9es ( direction :i* c h no connection ) ?is epic5tre4 ,besides ! ea/ & we/ l9es at ,nice1 ,m5tone1 & ,antibes1 !re are o!rs at ! same places :i* run nor? & s\? or ne>ly s4 ,pr(essor ,m]calli believes t !y 7 due to vibrations com+ f a second focus ly+ to ! s\? ( ,nice1 & !re are also sev]al l9es ( direction at m di/ant places :i* conv]ge t[>ds ! neighb\rhood ( ! correspond+ epic5tre4 ,?is conclusion receives unexpect$ support f "s ( ! be/ "t-records4 ,at ! railway-/ations ( ,loano & ,pietra ,ligure1 ! times ( occurr5ce 7 giv5 z #f;h4 #bjm4 #es4 & #f;h4 #bjm4 respectively--e/imates :i* are probably accurate to )9 a few seconds2 =1 at ! mom5t ( ! %ock1 ! (fic] :o br\ght ! exact "t along ! railway-l9e f ,g5oa 0 at ,loana1 & _h j pass$ ?r\gh ,pietra ,ligure4 ,on ! o!r h&1 ! e/imates = ,m5tone & ,nice--namely1 #f;h4 #ahm4 #ces4 & #f;h4 #aim4 #dcs41 if n equally exact1 _c err by _m seconds1 c]ta9ly n by s mu* z "o m9ute4 ,s9ce ! di/ances ( ,loana & ,pietra ,ligure f ! pr9cipal epic5tre are #ca & #cb miles1 & ^? ( ,m5tone & ,nice #bh & #cg miles1 x is !re=e cle> t ! vibrations :i* arriv$ fir/ at ,nice & ,m5tone mu/ h come f a local focus1 :]e ! impulse prec$$ t at ! pr9cipal focus by sev]al seconds4 ,,dep? ,,( ,,! ,,pr9cipal ,,focus4 ,inaccurate z are all ! me?ods ( det]m9+ ! dep? ( focus1 x seems probable1 z ,pr(essor ,issel argues1 t ! pr9cipal ,rivi]a focus 0 situat$ at a consid]able di/ance f ! surface4 ,9 no "p ( ! meizoseismal area 0 ! %ock a really viol5t "o2 yet its int5sity mu/ h fad$ v sl[ly outw>ds1 = x 0 /rong en\gh to /op clocks at places 9 ,switz]l& & else:]e n less ?an #bej miles f ! orig94 ,pr(essor ,m]calli reg>ds ,mallet's me?od ) great] fav\r ?an mo/ seismologi/s4 ,he po9ts to ! gradual increase 9 ! angle ( em]g5ce f ! out] zones di/urb$ by ! ,rivi]a e>?quake t[>ds ! meizoseismal area1 :]e sev]al good obs]vations 7 made f fissures 9 walls p>allel to ! dom9ant direction ( ! %ock4 ,! angles ( em]g5ce :i* he consid]s z mo/ tru/wor?y are ^? ( #ce at ,taggia1 #dj at ,oneglia1 & ab\t #cj at ,bordigh]a4 ,! correspond+ dep?s = ! focus are #aj4d1 #aj4d1 & #aa4f miles1 giv+ an av]age ( ab\t #aj-c_/d miles4 ,!re are no simil> obs]vations =?com+ = ! dep? ( ! second>y focus ne> ,nice & ,m5tone2 b ,pr(essor ,m]calli obs]ves t x mu/ h be5 %all[] ?an ! o!r1 = ! v]tical compon5t ( ! vibrations f ?is focus 0 mu* less s5sible ?an t ( ! motion com+ f ! pr9cipal focus4 ,,nature ,,( ,,! ,,%ock4 ,! ,d\ble ,%ock4--,9 ! valuable collection ( records made by ,pr(essors ,t>amelli & ,m]calli !re appe>s at fir/ sight to be ! utmo/ div]sity 9 ! evid5ce ) reg>d to ! nature ( ! %ock4 ,?us1 9 ! prov9ce ( ,p4 ,maurizio alone1 ! %ock 0 describ$ z subsultory fir/ & !n undulatory or vorticose at #be places1 undulatory & !n subsultory at #bb1 undulatory & !n subsultory & aga9 undulatory or vorticose at #ac1 & subsultory fir/1 !n undulatory1 & f9ally subsultory & vorticose at two places4 ,x is cle> t ! %ock 0 ( consid]able duration1 n less ?an half-a-m9ute z a rule1 & t !re 7 sev]al phases 9 ! movem5t2 & x w\ld seem t "o or m ( ^! phases may h pass$ unnotic$ ow+ to ! al>m occasion$ by ! %ock1 & to ! fact t mo/ ( ! obs]v]s 7 asleep :5 ! e>?quake began4 ,defects ( memory mu/ also h an influ5ce n to be neglect$1 =1 ev5 ) ! simple %ocks felt 9 ! ,briti% ,isles1 p]sons 9 ! same or neighb\r+ places diff] greatly 9 _! te/imony4 ,b1 if we conf9e ourselves to ! acc\nts ( c>eful p]sons alone1 ! discrepancies to a l>ge ext5t disappe>4 ,inde$1 all ov] ! ru9\s area 7,fig4 #cc7 ! %ock ma9ta9$ a ne>ly uni=m "*4 ,at ,oneglia1 = in/ance1 !re 7 two well-m>k$ phases1 ! fir/ ( :i* began ) a brief subsultory movem5t1 foll[$ by m horizontal undulations ( long] p]iod2 a pause1 la/+ b = an in/ant1 0 succe$$ by vibrations :i*1 ?\gh n v]tical1 7 highly incl9$ to ! horizon2 !y cont9u$ ?r\gh\t ! second phase1 b1 t[>ds ! end1 new undulations 7 sup]pos$1 & ^!1 com+ f diff]5t directions1 result$ 9 an app>5tly vorticose movem5t4 ,pr(essor ,m]calli repres5ts ! motion diagrammatically by ! curve a 9 ,fig4 #ce4 ,at ,diano ,m>9a1 z w be se5 f ! curve b1 ! %ock aga9 consi/$ ( two phases1 ea* beg9n+ ) a few subsultory vibrations & end+ ) horizontal undulations ( mu* long] p]iod4 ,9 ! fir/ phase1 ! undulations 7 m>k$ by a dom9ant direction1 b1 t[>ds ! close ( ! second phase1 !re 0 no det]m9ate direction1 & ! impression 0 aga9 t ( a vorticose %ock4 ,at ,savona1 ! movem5t1 :i* is repres5t$ by ! curve c1 mu/ h la/$ f tw5ty-five to ?irty seconds4 ,x also consi/$ ( two phases1 ) subsultory vibrations & undulations 9 ! same ord]2 & x 0 notic$ t ! second "p ( ! %ock 0 mu* /rong] ?an ! fir/4 ,accord+ to "s obs]v]s1 ! conclud+ movem5ts 7 vorticose4 ,illu/ration3 ,,fig4 #ce4--,nature ( %ock ( ,rivi]a e>?quake4 7,t>amelli & ,m]calli47 ,9 ! zone surr\nd+ ! ru9\s area1 ! v]tical compon5t ( ! motion 0 obs]v$ to dim9i% ) ! int5sity2 b1 9 o!r respects z well z 9 duration1 ! %ock reta9$ ! same g5]al =m4 ,at ,g5oa1 ,tur91 ,acqui1 ,aless&ria1 ,antibes1 & o!r places1 two di/9ct phases 7 p]ceiv$1 occasionally sep>at$ by a brief pause1 ! fir/ be+ inv>iably ! weak]4 ,at "s places1 ! obs]v]s speak ( two %ocks at ab\t #f4bj ,a4,m41 sep>at$ by an int]val ( a few seconds2 & ?is division 0 noticeable z f> z ,sal on ! %ore ( ,lake ,g>da & ,vic5za 9 ,v5etia4 ,only 9 ,switz]l& & o!r di/ricts ne> ! b\nd>y ( ! di/urb$ area did ! weak] "p ( ! %ock become ins5sible1 ! o!r consi/+ ( horizontal oscillations1 rem>kable = _! sl[ness & regul>ity1 & la/+ = z mu* z tw5ty or ?irty seconds4 ,we may ?us conclude1 ) ,pr(essor ,m]calli1 t ! e>?quake result$ f ! almo/ imm$iate succession ( two di/9ct %ocks1 9 ea* ( :i* ! ne>ly v]tical vibrations 7 m m>k$ at ! beg9n+1 :ile ! sl[] undulations pr$om9at$ t[>ds ! close1 ^? ( ! second phase g5]ally becom+ vorticose ?r\gh ! sup]position ( movem5ts com+ f diff]5t directions4 ,! second "p ( ! %ock 9 all ( ! m c>efully writt5 acc\nts is describ$ z ! /rong]1 especially z reg>ds ! subsultory vibrations 9 ! meizoseismal area2 except 9 ! imm$iate neighb\rhood ( ,nice1 :]e ! second phase 0 g5]ally reg>d$ z ! weak]1 or at any rate z n /rong] ?an ! fir/4 ,orig9 ( ! ,d\ble ,%ock4--,^! obs]vations %[1 n only t ! pr9cipal e>?quake consi/$ ( two di/9ct %ocks1 b also t ! %ocks orig9at$ 9 diff]5t foci4 ,=1 if ! vibrations ( bo? _h />t$ f "o focus1 ! second %ock w\ld h be5 ev]y:]e ! /rong]2 in/ead ( :i* !re 0 a small area ne> ,nice :]e ! int5sity ( ! fir/ 0 ! great]4 ,?is po9ts cle>ly to ! exi/5ce ( ano!r focus situat$ n f> f ,nice2 & x is evid5t t ! great] int5sity ( ! fir/ "p 9 t di/rict 0 due solely to ! proximity ( ?is focus1 =1 /ill f>!r to ! we/1 at ,antibes1 ! second "p 0 aga9 ! /rong]4 ,!re is ?us a /rik+ agreem5t 9 ! inf]5ces drawn f obs]vations on ! direction1 "t ( occurr5ce1 & nature ( ! %ock4 ,9 ! face ( su* concurr+ te/imony1 little d\bt c rema9 z to ! exi/5ce ( two foci1 "o to ! s\? ( ,oneglia & ! o!r to ! s\? ( ,nice1 ! initial impulse at ! latt] be+ decid$ly ! weak]1 & prec$+ t at ! ea/]n focus by an int]val ( "s seconds1 long en\gh at any rate = ! result+ vibrations to rea* ! ,oneglia focus & to spread beyond x be=e ! vibrations f t focus />t$ on _! outw>d j\rney4 ,seismographic ,records4--,9 #ahhg1 ! ,rivi]a & ! di/ricts adjo9+ x 7 unprovid$ ) accurately con/ruct$ seismographs4 ,! obs]vatories at ,aless&ria1 ,milan1 ,monza1 ,p>ma1 ,flor5ce1 & o!r places 9 ,italy conta9$ seismoscopes & o!r p5dulums1 & ^! all regi/]$ ! fact t an e>?quake _h occurr$1 & 9 _m cases trac$ a s]ies ( elliptical or elongat$ curves4 ,a record ( ! %ock 0 also giv5 by a ,cec*i seismograph at ,p]pignan 9 ,france1 b ! di/ance f ! epic5tre 0 too great to all[ details to be %[n4 ,! mo/ valuable record 0 t obta9$ f a ,cec*i seismograph at ! obs]vatory ( ,moncali]i1 ne> ,tur91 ab\t n9ety miles nor? ( ! pr9cipal epic5tre4 ,9 ?is seismograph1 ! p5dulums are provid$ ) po9t]s1 ! tips ( :i* t\* v]tical %eets ( pap] atta*$ to ! sides ( an upright rectangul> box4 ,:5 an e>?quake occurs1 ?is box is made to desc5d sl[ly ) a uni=m velocity1 :ile ! mov+ po9t]s trace curves ^u ! smok$ pap]4 ,! nor?-&-s\? compon5t ( ! horizontal motion is inscrib$ on ! %eet ( pap] fac+ we/1 & ! ea/-&-we/ compon5t on ! pap] fac+ s\?4 ,illu/ration3 ,,fig4 #cf4--,seismographic record ( ! ,rivi]a e>?quake at ,moncali]i4 7,d5za47 ,dur+ ! pr9cipal ,rivi]a e>?quake1 ! =m] p5dulum furni%$ an indi/9ct record1 :ile ! o!r trac$ ! diagram reproduc$ 9 ,fig4 #cf4 ,! movem5t1 z "h repres5t$1 began at ab\t #f;h4 #bam4 #ejs4 ,a4,m4 7mean "t ( ,rome7 ) a s]ies ( small tremors1 :i* la/$ = ab\t twelve seconds4 ,!n foll[$ "s l>ge oscillations1 always 9 a ne>ly ea/-&-we/ direction1 :i* at #f;h4 #bbm4 #bas4 gave place to a second s]ies ( tremors simil> to ^? at ! beg9n+ ( ! %ock1 b ( great] amplitude4 ,^! cont9u$ = at lea/ twelve seconds1 at ! end ( :i* "t ! motion ( ! smok$ pap] ceas$4 ,! total duration ( ! movem5t at ,moncali]i _c !re=e h be5 less ?an =ty-?ree seconds4 ,int]e/+ z ?is record is1 x is d\btful h[ f> x repres5ts accurately ! movem5t ( ! gr\nd4 ,! ,moncali]i in/rum5t 0 erect$ be=e ! mod]n type ( seismograph 0 design$1 9 :i* "s "p rema9s /eady1 or v ne>ly /eady1 dur+ ! complicat$ movem5ts ( ! gr\nd t take place 9 an e>?quake4 ,x w be notic$ t ! curve 9 ,fig4 #cf %[s no sign ( ! division ( ! %ock into two di/9ct p>ts1 & ?is may p]haps be due to ! sw++ ( ! p5dulum itself2 9 :i* case1 ! curve describ$ by ! po9t] w\ld be ! resultant ( ! oscillations ( ! gr\nd & ! prop] motion ( ! p5dulum4 ,,s\nd-,,ph5om5a4 ,! s\nds t prec$$ & accompani$ ! ,rivi]a e>?quake h attract$ b little /udy1 al?\gh !y seem to h be5 widely obs]v$4 ,no attempt 0 made to def9e ! limits ( ! area ov] :i* !y 7 audible2 b ,pr(essor ,m]calli /ates t 9 ! two out] zones 7,fig4 #cc7 ! s\nd g5]ally pass$ unobs]v$4 ,x 01 h[ev]1 he>d ne> ,piac5za 9 ,lomb>dy & ,reggio 9 ,emilia1 places :i* are ab\t #aae & #adj miles f ! pr9cipal epic5tre4 ,9 ! area 9 :i* ! %ock 0 mo/ viol5t1 ! s\nd resembl$ t ( tra9s & vehicles 9 motion2 :ile1 outside ?is area x g5]ally appe>$ to be l ! hiss+ ( a viol5t w9d4 ,9 only a few places 0 x comp>$ to detonations1 ! cra%es ( artill]y or di/ant ?und]4 ,"s obs]v]s describe ! s\nd z appe>+ at fir/ z if a /rong w9d 7 ris+1 & !n z ! ro>+ ( a heavy railway-tra9 pass+4 ,ne>ly all ! obs]v]s1 :o 7 awake at ! beg9n+ ( ! e>?quake1 agree 9 ass]t+ t ! s\nd di/9ctly prec$$ any movem5t ( ! gr\nd4 ,f ?is1 z 9 ! case ( ! ,&alusian e>?quake1 ,pr(essor ,m]calli inf]s t ! s\nd-vibrations travell$ ) ! great] velocity2 b1 z w be %[n 9 ,*apt] ,,viii41 ! g5]al prec$5ce ( ! s\nd admits ( ano!r & m probable explanation4 ,,! ,,unfelt ,,e>?quake4 ,if ! ,&alusian e>?quake fir/ drew g5]al att5tion to ! di/ant spread ( unfelt e>?-waves1 ! ,rivi]a e>?quake %[$ t ?is 0 no isolat$ ph5om5on4 ,we "k n[ t ! propagation ( su* waves is only limit$ by ! surface ( ! e>?1 b 9 #ahhg "s d\bt 0 felt at fir/ z to ! nature ( ! di/urbance1 :e!r x 0 magnetic or me*anical 9 its orig94 ,9 #ahhd1 ! only obs]vatories at :i* magnetographs 7 di/urb$ 7 ^? ( ,lisbon1 ,p>c ,sa9t-,maur 7ne> ,p>is71 ,gre5wi*1 & ,wilhelm%av54 ,9 #ahhg1 ! magnetographs regi/]$ ! ,rivi]a e>?quake at ^! & sev]al o!r obs]vatories1 ! di/ribution ( :i* is %[n 9 ,fig4 #cg4 ,9 ?is sket*-map1 ! position ( ! pr9cipal epic5tre is repres5t$ by ! small cross1 :ile ! ne>ly circul> l9e %[s ! b\nd>y ( ! di/urb$ area4 ,illu/ration3 ,,fig4 #cg4--;,di/ribution ( obs]vatories at :i* magnetographs 7 di/urb$ by ! ,rivi]a e>?quake4 ,?ree ( ! obs]vatories1 ^? ( ,nice1 ,lyons1 & ,p]pignan1 lie inside ?is area4 ,at ,nice 7:i* is ?irty-sev5 miles f ! pr9cipal epic5tre71 ,m4 ,p]rot9 /ates t ! magnetograph curves %[ no?+ ( any int]e/1 except a notable magnetic p]turbation on ! v]tical =ce curve1 ! "t ( :i*1 h[ev]1 is n /at$4#di ,at ,lyons 7#baa miles71 ! decl9ation1 horizontal =ce & v]tical =ce1 magnets 7 all di/urb$ at #f;h4 #bem4 #dgs4 ,a4,m41 & ,p]pignan 7#bfd miles71 all ?ree magnets1 b especially ^? = ! decl9ation & horizontal =ce1 7 set abruptly oscillat+ at #f;h4 #bem4 #bjs4 ,else:]e 9 ,france1 ! di/urbances 7 notic$ at ! obs]vatories ( ,p>c ,sa9t-,maur & ,monts\ris1 ne> ,p>is 7ab\t #ddg miles71 & at ,nantes 7#ech miles74 ,at ,p>c ,sa9t-,maur1 all ?ree curves %[ a v cle> trace ( ! e>?quake at #f;h4 #bem4 #ces41 ! oscillations la/+ sev]al m9utes1 & at ,monts\ris !y also began at ! same "t4 ,at ,nantes1 ! p]turbations 7 s slight t !y escap$ notice on a fir/ exam9ation4 ,9 ,au/ria1 di/urbances 7 obs]v$ at ,pola 7#bie miles7 & ,vi5na 7#ejf miles71 beg9n+ at #f;h4 #bhm4 #ces4 & #f;h4 #cjm4 #ces41 respectively4 ,!y rea*$ ,brussels 7#ebb miles7 at #f;h4 #bim4 #bgs41 & ,utre*t 7#fjj miles7 at #f;h4 #bhm4 #chs4#ej ,at ,wilhelm%av5 7#fij miles71 only ! v]tical =ce magnet 0 affect$1 ! oscillations beg9n+ at #f;h4 #cjm4 #ces41 & la/+ = f\rte5 m9utes4 ,at #f;h4 #bgm4 #ees41 ! decl9ation & horizontal =ce magnets ( ,gre5wi* obs]vatory 7#fdb miles7 7 set vibrat+1 b no simil> di/urbances 7 reveal$ by ! v]tical =ce curve or by ! two e>?-curr5t regi/]s4 ,at ,kew 7#feb miles71 ! horizontal =ce magnetograph 0 mov$ by ! e>?quake at ab\t #f;h4 #bim4 #ees4 ,! curves at ,/onyhur/ & ,falm\? %[ no sign ( any di/urbance1 nor d ^? at ,pawlovsk 9 ,russia1 or ,seville4 ,at ,lisbon 7#iea miles71 h[ev]1 ! ?ree curves indicate di/urbances at #f;h4 #cbm4 #ces41 b s feeble are !y t !y w\ld h escap$ discov]y if ! occurr5ce ( ! e>?quake _h be5 unkn[n4 ,! effects regi/]$ on ! magnetograms are q diff]5t f ^? :i* correspond to ord9>y magnetic p]turbations2 b !y are n unlike ^? produc$ by ! action ( ! mom5t>y curr5ts :i* are us$ = mak+ ! h\r-m>ks1 except t ! e>?quake-oscillations la/$ sev]al m9utes 7see ,fig4 #ba74 ,9 ea* case1 !n1 ! magnetic b>s mu/ h receiv$ a succession ( sev]al or _m impulses4 ,n[1 ! effect ( ^! impulses on ea* magnet mu/ dep5d on ! relations :i* exi/ betwe5 ! p]iod ( oscillation ( ! magnet1 ! rate ( damp+ ( su* oscillations1 & ! int]val betwe5 ! successive impulses4 ,also1 ! app>5t comm5cem5t ( ! ph5om5a may be delay$ if two impulses ( contr>y s5se %\ld foll[ "o ano!r be=e ! b> is p]ceptibly displac$4 ,x is !re=e to be expect$1 z ,m4 ,masc>t po9ts out1 t ! di/urbances ( ! ?ree in/rum5ts ne$ n be ( ! same ord] ( magnitude1 t ) diff]5t =ms ( app>atus ! effects may be v v>iable1 & t ! deflection ( "o in/rum5t may prec$e t ( ano!r at "o & ! same place4 ,9 all ! magnetographs1 ! record is made on photographic pap]1 :i* travels s sl[ly t ! "t ( a movem5t c only be asc]ta9$ to ! ne>e/ m9ute4 ,z ! di/urbances on ! ,fr5* curves 7 app>5tly almo/ simultane\s1 & z no two ( ! o!rs diff]$ 9 "t ( occurr5ce by m ?an five m9utes1 !re is ?us "s col\r = ,m4 ,masc>t's cont5tion t ! magnetic app>atus regi/]$1 n ! movem5ts ( ! gr\nd1 b ! passage ( electric curr5ts produc$ 9 ! gr\nd at a c]ta9 epo* ( ! e>?quake4#ea ,on ! o!r h&1 x is important to notice t1 9 ! c5tral "p ( ! di/urb$ area1 at ,nice1 two1 if n all ?ree1 ( ! magnetographs 7 unaffect$ at ! "t ( ! e>?quake4 ,at fir/ sight1 ?is fact seems equally oppos$ to a me*anical explanation ( ! di/urbance4 ,b1 :5 ! vibrations are v rapid1 z !y are 9 ! neighb\rhood ( ! epic5tre1 ! magnetic b>s1 ow+ to _! mode ( susp5sion1 h n suffici5t "t to be s5sibly deflect$ 9 ! brief int]val betwe5 successive phases ( ! impulse4 ,! magnetograms ( ! ,monts\ris obs]vatory %[1 = in/ance1 h>dly any p]ceptible trace ( di/urbance dur+ ! passage ( railway tra9s along two adjac5t l9es4 ,! f>!r1 h[ev]1 ! e>?-waves travel f ! orig91 ! long] becomes ! p]iod ( _! vibrations4 ,9 ,switz]l&1 !y 7 rem>kable = _! sl[ness1 ev5 to ! unaid$ s5ses4 ,?us1 at places m or less remote f ! ,rivi]a1 ! magnets w\ld receive impulses at int]vals approximat+ to _! own p]iods ( vibration1 & !y w\ld !n oscillate freely = "s "t4 ,aga91 not)/&+ "s v>iations1 x w be rem>k$ t on ! :ole ! ret>dation ( ! initial epo* ( ! di/urbances increases ) ! di/ance f ! epic5tre4 ,x ?us seems cle>1 ,i ?9k1 t ! cause ( ! di/urbances mu/ be s\ght 9 ! %ock itself2 al?\gh _! initial epo*s at diff]5t places are too r\ghly def9$ = asc]ta9+ ! velocity ) :i* ! e>?-waves travell$4 ,,effects ,,( ,,! ,,e>?quake ,,at ,,sea4 ,! ,rivi]a e>?quake1 ow+ to its subm>9e orig91 0 m>k$ by c]ta9 ph5om5a t 7 abs5t f ! o!r e>?quakes describ$ 9 ?is volume4 ,nature ( ! ,e>?quake at ,sea4--,at ! "t ( ! e>?quake1 sev]al vessels 7 close to ! epic5tral area4 ,"o1 ab\t ?ree miles (f ,diano ,m>9a1 0 %ak5 twice at ab\t #f4bj ,a4,m41 & s viol5tly t x seem$ z if ! ma/s w\ld be brok5 (f4 ,ano!r1 ab\t t5 miles s\? ( ,p4 ,maurizio1 also exp]i5c$ two %ocks1 a few m9utes ap>t1 z if ea* "t x _h /ruck ! bottom4 ,^! obs]vations are *iefly int]e/+ 9 %[+ t ! d\ble %ock 0 felt at sea z well z on l&4 ,z transv]se vibrations are n propagat$ ?r\gh wat]1 x foll[s t ! second "p ( ! %ock _c1 z "s ma9ta91 h be5 compos$ ( transv]se vibrations4 ,de/ruction ( ,fi%es4--,dur+ ! days imm$iately foll[+ ! e>?quake1 a l>ge numb] ( deep-sea fi%es 7 f\nd dead or half-dead ei!r 9 %all[ wat] or /r&$ on ! bea*1 especially 9 ! neighb\rhood ( ,nice4 ,among !m 7 num]\s specim5s1 mo/ly dead & float+1 ( ,alepocephalus ro/ratus1 a typical deep-sea =m1 sev]al ( ,pomatomus telescopium1 ,scopelus elongatus1 & ,s4 humboldti1 & _m ( ,d5tex macroph?almus & ,sp9ax nig]4 ,! dea? & flight ( ^! fi%es mu/ h be5 due to a sudd5 %ock1 almo/ l t caus$ by ! explosion ( dynamite1 & communicat$ simultane\sly to ! :ole surface ( _! bodies4 ,seismic ,sea-,waves4--,imm$iately aft] ! e>?quake1 ! sea retir$ a %ort di/ance1 v>i\sly e/imat$ at f t5 to ?irty metres1 lay+ b>e "s rocks t 7 usually imm]s$4 ,at ,p4 ,maurizio1 ! surface 0 l[]$ by a little m ?an a metre2 & aft] a few m9utes x rose to ne>ly a metre above its orig9al level1 return+ to x aft] a s]ies ( cont9ually-decreas+ oscillations4 ,at ,san ,remo1 a fall ( ab\t ! same am\nt took place1 ! sea return+ aft] five m9utes1 & a %ip an*or$ 9 ! h>b\r broke f h] moor+s4 ,aga91 at ,antibes1 ! sea 0 sudd5ly l[]$ by ab\t a metre1 s t %ips afloat 9 ! h>b\r 7 agr\nd = "s in/ants1 & !n return$ ) "s impetuosity to its orig9al level4 ,illu/ration3 ,,fig4 #ch4--,record ( tide-gauge at ,nice4 7,issel47 ,! evid5ce ( eye-witnesses is confirm$ by t ( ! tide-gauges at ,nice & ,g5oa1 ! curves ( :i* are reproduc$ 9 ,figs4 #ch & #ci4 ,at ,nice1 ! fir/ arre/ ( ! curve 9 its usual c\rse occurr$ at #f4cj ,a4,m42#eb ! sea-level sank some:at abruptly1 & aft] a few m>k$ oscillations gradually return$ to its normal position at #g4ej ,a4,m4 ,at ,g5oa1 ! %ock caus$ ! writ+-p5 ( ! tide-gauge to d5t ! pap] on :i* ! record is made1 & soon aft]w>ds ! curve %[s a s]ies ( irregul> oscillations1 ab\t eight tak+ place e h\r1 & gradually decreas+ until !y ceas$ to be p]ceptible ab\t two h\rs aft] ! pr9cipal e>?quake4 ,illu/ration3 ,,fig4 #ci4--,record ( tide-gauge at ,g5oa4 7,issel47 ,,miscellane\s ,,ph5om5a4 ,connection betwe5 ,geological ,/ructure & ! ,int5sity ( ! ,%ock4--,z ) ! ,&alusian e>?quake1 faulty con/ruction & defective mat]ials 7 responsible = mu* ( ! damage caus$ by ! ,rivi]a e>?quake4 ,b1 if we may judge f ! %>p local v>iations 9 its am\nt1 ! nature ( ! surface-rocks mu/ h ex]t$ a /ill m pot5t influ5ce4 ,at ,c]vo1 = example1 ! injury to prop]ty am\nt$ to less ?an #c p] head ( ! population2 at ,diano ,m>9a1 only two or ?ree miles to ! we/1 x rose to #bb p] head4 ,! dea?-rate at ,c]vo 0 ab\t "o-t5?1 & at ,diano ,m>9a ab\t #h-a_/b p] c5t4 ,aga91 at ,m5tone1 ! damage mu/ h be5 consid]able1 = ab\t #aee h\ses 7 r5d]$ un9habitable2 :ile ,monte ,c>lo1 only a few miles f>!r we/1 escap$ almo/ unh>m$4 ,n[1 ,m5tone & ,diano ,m>9a are = ! mo/ "p built on clay or alluvial deposits1 & ,monte ,c>lo on a f\ndation ( lime/one4 ,ev5 )9 ! limits ( a s+le t[n1 v>iations no less /rik+ 7 p]ceptible4 ,9 ,m5tone1 ! greate/ damage occurr$ to h\ses ( two /oreys built on alluvial soil 9 ! l[-ly+ p>ts ne> ! sea & 9 ! valleys4 ,! effect ( ! f\ndation 9 ?is "p 0 well %[n 9 ! case ( two equally well-built h\ses n m ?an #cjj y>ds ap>t4 ,"o 9 ! valley1 ) d\btful f\ndations1 0 v mu* %att]$2 ! o!r1 built on rock1 0 un9jur$4 ,! l>ge hotels1 especially ^? on high gr\nd1 suff]$ lea/1 few ( !m hav+ _! ma9 walls s]i\sly damag$4 ,^! build+s rise to heights ( f f\r to six /oreys1 & ( necessity h a firm & solid f\ndation4 ,pr(essors ,t>amelli & ,m]calli h made a c>eful /udy ( ! subject ( ?is section4 ,! g5]al conclusions at :i* !y arrive are t ! int5sity ( ! %ock 0 greate/ at places built on plioc5e conglom]ates1 b$s ( clay sup]pos$ on compact old rocks1 pat*es ( alluvium1 mioc5e =mations ( "s ?ickness =m$ ( repeat$ alt]nations ( /rata ( incoh]5t m>ls & lime/ones or compact s&/ones1 b$s ( *alk1 or some:at rott5 dolomite4 ,! %ock 0 also m de/ructive on ! summits ( isolat$ hills & ridges & on ! /eep slopes ( m\nta9s4 ,! influ5ce ( ! =m ( ! gr\nd 01 h[ev]1 subord9ate to t ex]t$ by ! nature ( ! subsoil4 ,?us1 at ,m5tone1 z we h se51 & also at ,nice & ,g5oa1 h\ses built on rock 9 elevat$ positions suff]$ mu* less ?an ^? situat$ on ! pla9s bel[ t are compos$ ( s& & rec5t alluvium4 ,obs]vations ( ! ,e>?quake 9 ,railway-,tunnels4--,obs]vations made 9 m9es at v>i\s times & places h prov$ t an e>?quake is felt less /rongly 9 deep work+s1 if felt at all1 ?an on ! surface ( ! gr\nd4 ,9 ! railway-tunnels ( ! ,rivi]a1 z ,pr(essor ,issel has %[n1 ! same result 0 e/abli%$ dur+ ! e>?quake ( #ahhg4 ,on ! l9e :i* runs nor?w>d f ,g5oa to ,pi$mont1 a tunnel m ?an five miles 9 l5g? pi]ces ! hilly gr\nd betwe5 ,pont]osso & ,ronco1 ! greate/ ?ickness ( rock above be+ ab\t a ?\s& feet4 ,at ! "t ( ! e>?quake1 ! tunnel 0 n ev]y:]e op5$ out to its full wid?1 & m5 7 at "w 9 diff]5t sections4 ,outside1 ! %ock 0 /rong en\gh to damage build+s4 ,inside1 at ab\t #bjj y>ds f ! s\? end1 only a feeble %ock 0 felt2 at #a1cej & #a1fbe y>ds1 "s bricks 7 se5 to fall f ! fac+1 b ! %ock 0 n o!rwise p]ceiv$1 & only a few y>ds f>!r no?+ unusual 0 notic$ by ! m5 at "w4 ,aga91 9 an unf9i%$ tunnel1 ab\t ?ree-qu>t]s ( a mile long1 betwe5 ! h>b\r ( ,g5oa & ! ea/]n railway-/ation1 ! vibrations 7 v slightly felt4 ,ev5 9 ! tunnels trav]s$ by ! coa/ railway f ,g5oa to ,nice--t is1 9 ^? situat$ )9 ! meizoseismal area--! %ock 0 ei!r v weak or n felt at all1 & n "o ( ! tunnels suff]$ ! slighte/ injury4 ,to m5 at "w inside a long tunnel1 ! conditions = obs]v+ e>?quakes are some:at imp]fect1 b ^! facts1 nev]!less1 br+ out v cle>ly ! inf]ior int5sity ( ! %ock at "s dep? bel[ ! surface4 ,,aft]-,,%ocks4 ,:ile ! unfelt e>?-waves ( ! great e>?quake 7 /ill w5d+ _! way ov] ! zone t surr\nds ! di/urb$ area1 ! c5tral regions 7 aga9 %ak51 at #f4bi ,a4,m41 by a %ock /rong en\gh to produce fre% ru9s 9 ! /rick5 t[ns along ! coa/4 ,ne>ly two & a half h\rs ( quiet foll[$1 brok5 only by a few subt]ranean rumbl+s 9 ! c5tral "p ( ! meizoseismal area4 ,!n1 at #h4ea ,a4,m41 occurr$ ano!r %ock1 %ort & %>p1 & inf]ior 9 /r5g? only to ! pr9cipal e>?quake4 ,bo? ( ^! aft]-%ocks 7 felt 9 ,we/]n ,switz]l&2 inde$1 !y 7 p]ceptible ne>ly z f> z ! great %ock2 ! second1 h[ev]1 a little f>!r ?an ! fir/1 = x alone 0 notic$ at su* places z ,vic5za1 ,=l1 & ,flor5ce4 ,! %ock at #f4bi 0 usually describ$ z long & its vibrations z undulatory only2 t at #h4ea z r subsultory ?an undulatory & ( v brief duration4 ,! latt]1 h[ev]1 0 foll[$ aft] an int]val ( a few seconds by ano!r %ock s weak t x g5]ally pass$ unobs]v$4 ,bo? %ocks 7 prec$$ by a rumbl+ s\nd4 ,dur+ ! next two days1 tremors & e>?-s\nds 7 frequ5t 9 ! ,rivi]a2 once an h\r1 on an av]age1 ! great] "p ( ! meizoseismal area 0 %ak5 by vibrations m or less slight4 ,b1 betwe5 "o %ock & ano!r1 at ,diano ,m>9a & ,alassio1 & ev5 z f> z ,nice1 x only requir$ att5tion f a c>eful obs]v] to p]ceive an almo/ cont9ual ?robb+ ( ! gr\nd4 ,only "o ( ^! %ocks1 t ( ,febru>y #bd?1 at #b4aj ,a4,m41 0 /rong en\gh to cause slight damage to build+s4 ,x di/urb$ an area1 n exce$$ by any ( ! lat] %ocks1 ! b\nd>y ( :i*1 %[n by ! dott$ l9e ,a 9 ,fig4 #cc1 ext5ds to ! nor? & ea/ z f> z ,piac5za & ,spezia1 :ile to ! we/ x includes ,cannes4 ,! c5tre ( ! curve s drawn lies on l&1 b1 z ! %ock 0 n felt 9 ,corsica1 !re is no evid5ce z to ! s\!rly ext5sion ( ! di/urb$ area2 & x is probable1 z ,pr(essor ,m]calli sugge/s1 t ! %ock orig9at$ 9 ! ea/]n or ,oneglia focus ( ! great e>?quake4 ,aft] ,febru>y #be?1 slight %ocks 7 felt dur+ ! next =tnight1 at ! rate ( ?ree or f\r a day1 until ,m>* #aa?1 :5 ! la/ aft]-%ock result+ 9 slight damage occurr$ at ab\t #c4ab ,p4,m4 ,! b\nd>y ( its di/urb$ area1 repres5t$ 9 ,fig4 #cc by ! dott$ l9e ,b1 passes a little to ! ea/ ( ,savona1 & !n ?r\gh ,aless&ria1 ,moncali]i1 & ,m>seilles4 ,! %ock1 h[ev]1 0 n obs]v$ 9 ,corsica1 s t ! exact position ( ! epic5tre is unkn[n2 b ,pr(essor ,m]calli believes x to co9cide ) ! we/]n or ,nice epic5tre ( ! pr9cipal e>?quake4 ,at ! mom5t ( ! %ock1 ! sea 0 obs]v$ f ,alassio to curl & to rise slightly1 :ile ! tide-gauge at ,nice1 :i* _h trac$ a cont9u\s curve e>li] 9 ! day1 %[$ a *>act]i/ic not* ab\t #c4g ,p4,m4 ,( ! rema9+ aft]-%ocks1 only two atta9$ any notable degree ( /r5g?4 ,"o1 on ,may #bj? at ab\t #h4ae ,a4,m41 di/urb$ an area ne>ly conc5tric ) t ( ! great e>?quake1 & ) a b\nd>y co9cid+ ne>ly ) ! isoseismal #b 9 ,fig4 #cc4 ,aga91 on ,july #ag? at #aa4cj ,p4,m41 occurr$ a %ock felt ov] an area ne>ly z l>ge z t di/urb$ on ,febru>y #bd? at #b4aj ,a4,m41 & situat$ 9 ! same "p ( ! c\ntry4 ,altoge!r1 dur+ ! ye> foll[+ ! ,rivi]a e>?quake1 ,pr(essor ,m]calli records #aij aft]-%ocks1 mo/ ( !m slight or only j felt4 ,) ! exception ( ! fir/ two 7on ,febru>y #bcrd71 none 0 obs]v$ outside ! isoseismal #d ( ! pr9cipal e>?quake 7,fig4 #cc72 &1 ( ! re/1 only ! f\r ^: dates are giv5 above di/urb$ an area ( m ?an "o-eigh? ( t ( ! great %ock4 ,"s ( !m1 l ! %ock ( ,m>* #aa?1 7 /rong] 9 ! we/]n "p ( ! meizoseismal area2 b ! majority affect$ mo/ ! ea/]n portion & seem to be closely associat$ ) ! ,oneglia focus4 ,f ,febru>y #bf? to ,april #bj?1 ,pr(essor ,rumi made obs]vations on ! aft]-%ocks by means ( ! ,f\cault p5dulum erect$ at ,g5oa = demon/rat+ ! rotation ( ! e>?4 ,9 ne>ly e case1 ! oscillations took place along a nor?-ea/ & s\?-we/ l9e1 or 9 ! same direction z ! fir/ great %ock--a resemblance :i* supports ! inf]5ce t _m ( ! aft]-%ocks orig9at$ )9 ! ,oneglia focus4 ,,orig9 ,,( ,,! ,,e>?quakes4 ,rec5t ,movem5ts 9 ! ,rivi]a4--,! e>lie/ movem5ts t result$ 9 ! great range ( ! ,m>itime ,alps & ! ,ligurian ,ap5n9es date f pre-,c>bonif]\s times1 :5 ! c5tral cry/all9e massifs 9 "p em]g$4 ,at ! end ( ! ,liassic epo*1 ! second>y =mations ( ! di/rict 7 uplift$1 & x 0 at ?is "t t ! range assum$ its *>act]i/ic curv$ =m4 ,lat] /ill1 at ! close ( ! ,eoc5e p]iod1 an elevation ( m ?an #ijjj feet took place1 = upp] ,eoc5e b$s are f\nd at ?is height 9 ! ,m>itime ,alps4 ,s9ce t "t1 o!r important movem5ts h occurr$4 ,plioc5e deposits h be5 f\nd 9 ! ,rivi]a at an altitude ( #a1hjj feet4 ,rec5t s\nd+s 9 ! ,gulf ( ,g5oa h also %[n t all ! valleys ( ! ,rivi]a betwe5 ,nice & ,g5oa are cont9u$ f> bel[ ! level ( ! sea to dep?s ( n less ?an #cjjj feet4 ,?us1 at ! end ( ! ,plioc5e or beg9n+ ( ! ,quat]n>y p]iod1 !re 0 an elevation ( ne>ly #ejjj feet1 accompani$ or foll[$ by ! erosion ( ! valleys :i*1 lat] on1 dur+ ! ,quat]n>y p]iod1 7 subm]g$ ab\t #cjjj feet4 ,ev5 9 /ill m rec5t times1 probably 9 ! ,paloli?ic age1 m9or movem5ts cont9u$4 ,traces ( rec5t elevation1 v>y+ 9 am\nt f a few feet to sixty feet or m1 occur at ! ,balzi ,rossi 9 ! ,alpes ,m>itimes1 ne> ,b]geggi1 & 9 ,g5oa2 :ile evid5ces ( subm]g5ce are to be f\nd ne> ,monaco1 at ,beaulieu & at ,diano ,m>9a4 ,x is important to notice t ! great movem5ts dat+ f ! end ( ! ,eoc5e p]iod are almo/ conf9$ to ! ,m>itime ,alps & ! we/]n portion ( ! ,rivi]a4 ,9 ! p>ts ( ,pi$mont ly+ to ! nor? ( ,cuneo & 9 ! ea/]n ,rivi]a1 !y produc$ h>dly any s5sible effect4 ,seismic ,hi/ory ( ! ,rivi]a4--,! movem5ts j ref]r$ to are ^? :i*1 9 c\rse ( "t1 h become s5sible to ! eye4 ,!y repres5t ! sum ( a long-cont9u$ s]ies ( displacem5ts t may once h be5 on a l>ge scale1 b are n[ comp>atively small4 ,! e>?quakes t occur 9 ! ,rivi]a %[1 h[ev]1 t ! f9al /age has n yet be5 rea*$4 ,_! epic5tres indicate ! regions 9 :i* slips are /ill tak+ place1 & ! magnitude ( ^! slips is r\ghly measur$ by ! int5sity ( ! result+ %ocks4 ,! map 9 ,fig4 #dj is "o ( a s]ies drawn by ,pr(essor ,m]calli to repres5t ! di/ribution ( seismic activity 9 ,pi$mont & ! ,rivi]a4 ,x corresponds to ! p]iod f #ahja to #ahie4 ,! :ole area is divid$ into a numb] ( seismic di/ricts1 ea* ( :i* is di/+ui%$ by a p>ticul> degree ( activity4 ,9 e/imat+ ?is quantity1 ,pr(essor ,m]calli takes int5sity z well z frequ5cy into acc\nt4 ,?us1 ! l[e/ degree1 repres5t$ by ! lighte/ t9t ( %ad+1 corresponds to "o or two /rong e>?quakes ) a few mod]ate or slight %ocks2 ! eigh? & highe/ to f\r or five ru9\s or disa/r\s e>?quakes foll[$ by tra9s ( aft]-%ocks4 ,! map %[s v cle>ly t1 dur+ ! la/ c5tury1 ! seismic activity 0 greate/ 9 ! ,m>itime ,alps & ! we/]n ,rivi]a--t is1 9 ! v di/ricts 9 :i* ! rec5t m\nta9-mak+ movem5ts h be5 mo/ conspicu\s4#ec ,illu/ration3 ,,fig4 #dj4--;,di/ribution ( seismic activity 9 ! ,rivi]a4 7,m]calli47 ,9 all ^! di/ricts1 ,pr(essor ,m]calli di/+ui%es sev]al well-m>k$ seismic c5tres1 to ea* ( :i* he traces ! orig9 ( two or m e>?quakes4 ,9 ! di/ricts ) :i* we are at pres5t conc]n$1 ^? ( ! ,alpes ,m>itimes & ! we/]n ,rivi]a1 ! mo/ important c5tres are situat$ ne> ,oneglia 79 ! sea71 ne> ,taggia1 9 ! valleys ( ! ,vesubia & ,t9ea 7ne> ,nice71 & 9 ! sea to ! s\? ( ,nice4 ,to ! fir/ ( ^! c5tres belongs ! disa/r\s e>?quake ( ,febru>y #bcrd1 #ahhg1 z well z its aft]-%ocks on ,febru>y #bd?1 ,may #bj?1 ,july #ag?1 & ,septemb] #cj? ( ! same ye>1 also ! ru9\s e>?quakes ( #afab & #ahed1 & sev]al o!rs ( a less] degree ( int5sity4 ,all ( ^! 7 longitud9al e>?quakes1 ! axes ( _! meizoseismal areas be+ p>allel to ! neighb\r+ m\nta9-ranges4 ,a few miles to ! we/ ( ,oneglia lies ! ,taggia c5tre1 ) :i* 7 connect$ ! disa/r\s e>?quake ( #ahca1 ! viol5t e>?quake ( #ahgd1 & o!r /rong or v /rong %ocks4 ,^! 7 = ! mo/ "p transv]sal e>?quakes1 _! axes be+ p]p5dicul> to ^? ( ! ,oneglia c5tre4 ,"s ( ! /ronge/ e>?quakes 9 ?is region orig9at$ 9 a c5tre ly+ to ! nor? ( ,nice 9 ! valleys ( ! ,vesubia & ,t9ea4 ,among !m may be m5tion$ ! ru9\s e>?quakes ( #adid1 #aeef1 #aefd1 & #afdd1 & probably also ! disa/r\s e>?quake ( #abbg4 ,a f\r? c5tre1 & "o ( consid]able int]e/1 is t :i* lies at sea1 a %ort di/ance to ! s\? ( ,nice1 & ne>ly along ! cont9uation ( ! valleys above-m5tion$4 ,?is is ! second>y c5tre ( ! e>?quake ( #ahhg1 & probably also ( t ( ,decemb] #bi?1 #aeed4 ,x is occasionally 9 action ap>t f ! ,oneglia c5tre1 z on ,novemb] #bg?1 #agga1 ,june #ai?1 #ahjf1 & ,decemb] #ba/1 #ahfa2 b su* %ocks1 ?\gh r /rong1 nev] rea* a high degree ( int5sity4 ,orig9 ( ! ,e>?quakes ( #ahhg4--,! mo/ important feature 9 ! pr9cipal e>?quake ( #ahhg is its orig9ation 9 two di/9ct foci1 :i* are sometimes 9 action almo/ simultane\sly1 b m (t5 sep>ately4 ,! e>?quakes belong+ to ! two foci diff] greatly 9 int5sity & numb]1 & ! /rong] "p ( ! %ock 9 #ahhg orig9at$ 9 ! focus associat$ ) ! m disa/r\s & m frequ5t e>?quakes4 ,! exi/5ce ( two foci w\ld ( c\rse give rise to a meizoseismal area elongat$ 9 ! direction ( ! l9e jo9+ !m4 ,x is cle>1 h[ev]1 t ! ,oneglia focus 0 also ext5d$ 9 ! same direction2 =1 9 ! aft]-%ock ( ,febru>y #bd?1 ! isoseismals drawn by ,pr(essor ,m]calli are p>allel to ?is l9e2 & ?is 0 also ! case 9 ! %ock ( ,m>* #aa?4 ,z bo? foci 7 "u ! sea1 x is difficult to locate !m ) precision2 b x seems v probable t !y occupy portions ( a subm>9e fault t runs p>allel or ne>ly s to ! ,ap5n9e axis betwe5 ! m]idians ( ,oneglia & ,nice4 ,a brief p]iod ( prep>ation is a *>act]i/ic ( ! ,rivi]a e>?quakes4 ,9 #ahhg1 two at lea/ ( ! prelim9>y %ocks on ,febru>y #bcrd 7^? ( ab\t #b & #e ,a4,m47 orig9at$ 9 ! ,oneglia focus4 ,at #f4bj ,a4,m4 ! fir/ & weak] movem5t took place 9 ! we/]n focus2 &1 a few seconds aft] ! result+ vibrations rea*$ ! ea/]n focus1 ! second & great] slip took place !re4 ,! occurr5ce ( seismic sea-waves is probably evid5ce ( ! =mation ( a small1 ?\gh s5sible1 fault-sc>p 9 ! same region4 ,to relieve ! additional /resses ?us br\ght into action along ! fault-surface1 num]\s small slips took place 9 diff]5t p>ts1 "s z f> to ! we/ z ! ,nice focus1 b ! great] numb] probably )9 or close to ! focus 9 ! neighb\rhood ( ,oneglia4 ,,ref]5ces4 #a4 ,,b]telli1 ,t4--,oss]vazioni fatte 9 occasione di una escursione sulle ,rivi]a ,ligure di pon5te dopo i t]remoti ivi seguiti nell' anno #ahhg4 ,boll4 ,m5s4 dell' ,oss4 di ,moncali]i1 vol4 viii41 #ahhh1 ,nos4 #f1 #g1 #h4 #b4 ,,*>lon1 ,e4--,note sur le tremblem5t de t]re du #bc fvri] #ahhg4 ,bull4 del ,vulc4 ,ital41 anno xiv41 #ahhg1 pp4 #ah-bc4 #c4 ,,d5za1 ,f4--,alcune notizie sul t]remoto del #bc febbraio #ahhg 7,tur974 #d4 ,,issel1 ,a4--,il t]remoto del #ahhg 9 ,liguria4 ,boll4 del ,r4 ,com4 ,geol4 d',italia1 anno #ahhg1 supplem5to1 pp4 #a-bjg4 #e4 ,,m]calli1 ,g4--,i t]remoti della ,liguria e del ,piemonte4 7,naples1 #ahig1 #adf pp47 #f4 ,,oddone1 ,e4--,i dati sismici della ,liguria 9 rapporto alla frequ5za ed alla p]iodicit4 ,boll4 della ,soc4 ,sismol4 ,ital41 vol4 ii41 #ahif1 pp4 #adj-aea4 #g4 ,,(fret1 ,a4--,sur le tremblem5t de t]re du #bc fvri] #ahhg4 ,discussion des heures obs]vs dans la zone pic5trale4 ,p>is1 ,acad4 ,sci41 ,compt4 ,r5d41 vol4 civ41 #ahhg1 pp4 #aaej-aaec4 #h4 ----4 ,tremblem5ts de t]re du #bc fvri] #ahhg4 ,heures de l'arrive des sec\sses en dehors de l'pic5tre4 ,ibid41 pp4 #abch-abdb4 #i4 ,,rossi1 ,m4,s4 ,,de4--,relazione sui t]remoti del febbraio #ahhg4 ,bull4 del ,vulc4 ,ital41 anno xiv41 #ahhg1 pp4 #e-ag4 #aj4 ----4 ,bibliografia3 ,sul t]remoto ligure del #bc febbraio #ahhg4 ,ibid41 pp4 #fj-fb1 #ajg-aab1 #aae-abh4 #aa4 ,,t>amelli1 ,t41 & ,g4 ,,m]calli4--,il t]remoto ligure del #bc febbraio #ahhg4 ,annali dell' ,uff4 ,c5tr4 di ,meteor4 e di ,geod941 vol4 viii41 p>te iv41 #ahhh4 7,roma1 #bih pp47 #ab4 ,,uzielli1 ,g4--,le commozioni telluri*e e il t]remoto del #bc febbraio #ahhg 7,tur974 #ac4 ,nature1 vol4 xxxv41 #ahhg1 pp4 #dch1 #dfb1 #ecd-ece2 vol4 xxxvi41 #ahhg1 pp4 #d1 #aea-aeb4 #ad4 ,p>is1 ,acad4 ,sci4 ,compt4 ,r5d41 vol4 civ41 #ahhg1 pp4 #eef-eeg1 #fjf-fab1 #fcd-fce1 #fei-ffg1 #gdd-gde1 #geg-geh1 #gei-gfj1 #gfd-gff1 #hbb-hbc1 #hcj-hce1 #hhd-hij1 #iej-iea1 #ajhh-ajhi1 #abdc-abde1 #acej-aceb1 #adaf-adai2 vol4 cv41 #ahhg1 pp4 #bjb-bjc2 vol4 cviii41 #ahhi1 p4 #aahi2 vol4 cix42 #ahhi1 pp4 #afd-aff1 #bgb-bgd1 #ffj4 ,,footnotes3 #dg ,! above times & all o!rs 9 ?is *apt] are giv5 9 ,rome mean "t1 :i* is #ejm4 e>li] ?an ,gre5wi* mean "t4 #dh ,pr(essor ,uzielli has also publi%$ a map ( ! isoseismal l9es = ! ,italian "p ( ! di/urb$ area4 #di ,x seems d\btful :e!r ?is movem5t 0 connect$ ) ! e>?quake4 ,m4 ,(fret does n include ,nice 9 8 li/ ( obs]vatories at :i* magnetographs 7 di/urb$4 #ej ,?is is ! "t giv5 by ,m4 ,(fret4 ,accord+ to ,m4 ,masc>t1 x %\ld be #f;h4 #bem4 #djs4 #ea ,9 ord] to te/ ! tru? ( ?is explanation1 ,m4 ,m\reaux susp5d$ a b> ( copp] at ! ,p>c ,sa9t-,maur obs]vatory by two ?reads 9 ! same way z ! horizontal =ce-magnet4 ,! direction ( ?is b> 0 also regi/]$ photographically1 & x rema9$ unmov$ dur+ ! ,v]ny e>?quake ( ,july #ab?1 #ahhi1 & ! ,d>danelles e>?quake ( ,octob] #be?1 #ahhi1 :ile "o or m ( ! magnets 7 di/urb$4 ,! exp]im5t1 h[ev]1 0 ineffective2 =1 9 ord] t ! magnet may re/ 9 a horizontal position1 its c5tre ( gravity mu/ be at unequal di/ances f ! two po9ts ( support4 #eb ,! h\r-m>ks 9 ,fig4 #ch ref] to ,p>is mean "t1 & ^? 9 ,fig4 #ci to ,g5oa mean "t4 #ec ,9 ! sev5te5? c5tury1 ! maximum seismic activity 0 manife/$ 9 ! neighb\rhood ( ,nice1 & 9 ! eighte5? c5tury 9 ,pi$mont4 ,,*apt] ,,vii4 ,,! ,,japanese ,,e>?quake ,,( ,,octob] #bh,,?1 #ahia4 ,al?\gh sev]al ye>s h elaps$ s9ce ! occurr5ce ( ! greate/ ( ,japanese e>?quakes1 ! f9al report t w embody ! lab\rs ( all its inve/igators is yet to be writt54 ,sev]al important contributions to x1 h[ev]1 h already be5 made4 ,pr(essor ,koto1 9 an admirable memoir1 has trac$ ! c\rse ( ! great fault-sc>p & discuss$ ! orig9 ( ! e>?quake2 ,pr(essor ,omori1 ) equal c>e & ?or\ghness1 has inve/igat$ ! unrivall$ s]ies ( aft]-%ocks2 ,mr4 ,cond] /udi$ ! damag$ build+s f an ar*itect's po9t ( view2 ,pr(essor ,tanakadate & ,dr4 ,nagaoka devot$ !mselves to a re-det]m9ation ( ! magnetic elem5ts ( ! c5tral di/rict1#ed :ile1 by ! compilation ( 8 great catalogue ( ,japanese e>?quakes dur+ ! ye>s #ahhe-ib1 ,pr(essor ,milne has provid$ ! mat]ials = a fur!r analysis ( ! m9or %ocks t prec$$ & foll[$ ! pr9cipal e>?quake4 ,! "p ( ,japan ov] :i* ! e>?quake 0 s5sibly felt is %[n 9 ,fig4 #da4 ,! small black area 9 ! c5tre is t 9 :i* ! %ock 0 mo/ sev]e & ! pr9cipal damage to life & prop]ty occurr$4 ,! o!r b&s1 m or less d>kly %ad$ accord+ to ! great] or less int5sity ( ! %ock1 w be ref]r$ to aft]w>ds4 ,fig4 #de repres5ts ! meizoseismal area on a l>g] scale2 &1 z ! great] "p ( x lies )9 ! two prov9ces ( ,m9o & ,ow>i1 ! e>?quake is g5]ally kn[n among ! ,japanese !mselves z ! ,m9o-,ow>i e>?quake ( #ahia4 ,illu/ration3 ,,fig4 #da4--,sket*-,map ( ,di/urb$ ,area & ,isoseismal ,l9es4 7,masato47 ,,! ,,meizoseismal ,,area4 ,m ?an half ( ! meizoseismal area occupies a l[ flat pla9 ( n less ?an #djj squ>e miles 9 ext5t4 ,on all sides b ! s\?1 ! pla91 :i* is a cont9uation ( ! depression =m+ ! ,sea ( ,is1 is surr\nd$ by m\nta9 ranges1 ^? to ! we/1 nor?1 & nor?-ea/ be+ built up ma9ly ( ,palozoic rocks1 & ^? on ! ea/ side ( granite4 ,a network ( riv]s & canals conv]ts :at might o!rwise h be5 unproductive gr\nd into "o ( ! mo/ f]tile di/ricts 9 ,japan4 ,a great g>d51 z x has be5 aptly t]m$1 ! :ole pla9 is cov]$ ) rice-fields1 & supports a population ( ab\t #ghg to ! squ>e mile--a d5sity :i* is exce$$ 9 only six c\nties ( ,engl&4 ,z a rule1 ! soil is a loose1 incoh]5t1 f9e s&1 ) b little clayey matt]2 & x is1 no d\bt1 to its s&y nature t ! disa/r\s effects ( ! e>?quake 7 l>gely due4 ,9 ! nor!rn half ( ! di/rict1 ! meizoseismal area is mu* n>r[]1 & "h x crosses a great m\nta9-range runn+ f s\?-we/ to nor?-ea/ & sep>at+ ! riv]-sy/ems ( ! ,japan sea f ^? ( ! ,pacific4 ,to ! nor?1 ! meizoseismal area t]m9ates 9 ano!r pla91 9 ! c5tre ( :i* lies ! city ( ,fukui1 :]e ! de/ructiv5ess ( ! e>?quake 0 only inf]ior to t exp]i5c$ 9 ! prov9ces ( ,m9o & ,ow>i4 ,!re is also a deta*$ portion ( ! area ly+ to ! ea/ ( ,lake ,biwa1 b x is unc]ta9 :e!r ! exceptional int5sity !re 0 due to ! nature ( ! gr\nd or to ! occurr5ce ( a second>y or sympa!tic e>?quake 9 its imm$iate neighb\rhood4 ,illu/ration3 ,,fig4 #db4--;,g5]al ,plan ( ,geological ,/ructure ( ,meizoseismal ,area4 7,koto47 ,! g5]al plan ( ! geological /ructure ( ! c5tral di/rict is repres5t$ 9 ,fig4 #db4 ,! ?ick l9e1 p>tly cont9u\s & p>tly brok51 %[s ! c\rse ( ! great fault1 to ! gr[? ( :i* ! e>?quake *iefly ow$ its orig92 :ile ! ?9 cont9u\s l9es repres5t ! *ang+ direction ( /rike ( ! ,palozoic rocks :i* surr\nd ! ,m9o-,ow>i pla91 & ! arr[heads ! direction ( ! dip4 ,x w be se5 t ! direction ( ! /rike =ms an ,s-%ap$ curve1 & x is cle> t ! pres5t torsion-/ructure ( ! di/rict c\ld n h be5 produc$ )\t ! =mation ( _m fractures at "r angles & p>allel to ! l9es ( /rike4 ,pr(essor ,koto po9ts out t ! regul> & p>allel valleys ( ! riv]s ,tokuno-yama1 ,neo1 ,mugi1 & ,itatori1 indicat$ by brok5 l9es 9 ,fig4 #db1 h probably be5 excavat$ along a s]ies ( transv]se fractures runn+ f nor?-we/ to s\?-ea/2 :ile fractures :i* are p>allel to ! l9e ( /rike may be responsible = ! zigzag c\rse ( ! valleys4 ,,damage ,,caus$ ,,by ,,! ,,e>?quake4 ,! great e>?quake occurr$ at #f4cg ,a4,m41 practically )\t w>n+1 & 9 a few seconds ?\s&s ( h\ses 7 levell$ ) ! gr\nd4 ,)9 ! :ole meizoseismal area !re 0 h>dly a build+ left undamag$4 ,! road f ,nagoya to ,gifu1 m ?an tw5ty miles 9 l5g?1 & =m]ly bord]$ by an almo/ cont9u\s succession ( villages1 0 conv]t$ into a n>r[ lane betwe5 two long drawn-out banks ( dbris4 ,9 "s /reets1 says ,pr(essor ,milne1 x appe>$ z if ! h\ses _h be5 pu%$ d[n f ! end1 & !y _h fall5 l a r[ ( c>ds4 ,or1 aga91 a mass ( heap$-up rubbi% might be pass$1 :]e /icks & e>? & tiles 7 s ?or\ghly mix$ t traces ( /reets or indications ( build+ _h be5 entirely lo/4 ,at ,gifu1 ,ogaki1 ,kasamatsu1 & o!r t[ns1 fires broke out aft] ! e>?quake4 ,9 ,kasamatsu ! de/ruction 0 absolutely complete2 no?+ 0 left b a heap ( pla/]1 mud1 tiles1 & *>r$ timb]s4 ,at ,ogaki1 n m ?an ?irty out ( #hjjj h\ses rema9$ /&+1 & ^! 7 all mu* damag$4 ,)9 ! :ole di/rict1 accord+ to ! (ficial returns1 #aig1ecj build+s 7 entirely de/roy$1 #gh1bif half de/roy$1 & #e1icd %att]$ & burnt2 :ile #g1bgi p]sons 7 kill$1 & #ag1cic 7 w\nd$4 ,next to build+s1 ! embankm5ts :i* bord] ! riv]s & canals suff]$ ! mo/ s]i\s damage1 no less ?an #cag miles ( su* works hav+ to be repair$4 ,railway-l9es 7 twi/$ or b5t 9 _m places1 ! total l5g? demoli%$ be+ m ?an t5 miles4 ,9 cutt+s1 tw5ty feet or m 9 dep?1 bo? rails & sleep]s 7 unmov$2 x 0 on ! pla9s t ! effects ( ! e>?quake 7 mo/ m>k$4 ,! gr\nd appe>$ z if pil$ up into bol/]-l ridges betwe5 ! sleep]s1 & 9 _m places ! sleep]s _h mov$ end-ways4 ,:5 ! l9e cross$ a small depression 9 ! g5]al level ( ! pla91 ! :ole ( ! track 0 b[$1 z if ! gr\nd 7 p]man5tly compress$ at su* places4 ,effects ( compression1 says ,pr(essor ,milne1 7 mo/ m>k$ on "s ( ! embankm5ts1 :i* gradually raise ! l9e to ! level ( ! bridges4 ,on "s ( ^!1 ! track 0 b5t 9 & out until x resembl$ a s]p5t wriggl+ up a slope4444 ,close to ! bridges ! embankm5ts _h g5]ally disappe>$1 & ! rails & sleep]s 7 hang+ 9 ! air 9 huge cat5>ies4 ,,isoseismal ,,l9es ,,& ,,di/urb$ ,,area4 ,! l& area di/urb$ by ! e>?quake & ! diff]5t isoseismal l9es are %[n 9 ,fig4 #da4 ,! mo/ sev]ely %ak5 di/rict1 t 9 :i* ! de/ruction ( build+s & eng9e]+ works 0 ne>ly complete1 conta9s an area ( #d1bhf squ>e miles1 or ab\t two-?irds t ( ,york%ire4 ,?is is indicat$ on ! map by ! black portion4 ,outside ?is lies ! v sev]ely %ak5 di/rict1 #ag1cbe squ>e miles 9 area1 ext5d+ f ,kobe on ! we/ to ,%izuoka on ! ea/1 9 :i* ord9>y build+s 7 de/roy$1 walls fractur$1 embankm5ts & roads damag$1 & bridges brok5 d[n4 ,! ?ird or sev]ely %ak5 di/rict conta9s #bj1ahc squ>e miles2 & 9 ?is "s walls 7 crack$1 p5dulum clocks /opp$1 & furniture1 crock]y1 etc41 ov]?r[n4 ,tokio & ,yokohama lie j )9 ?is area4 ,9 ! f\r? region ! %ock 0 weak1 ! motion be+ di/9ctly felt1 b n caus+ p to run out-(-doors2 & 9 ! fif? x 0 slight1 or j suffici5t to be felt4 ,^! two regions toge!r include an area ( #ea1igf squ>e miles4 ,?us1 ! l& area di/urb$ am\nts altoge!r to #ic1ggj squ>e miles--i4e41 to a little m ?an ! area ( ,great ,brita94 ,accord+ to ,pr(essor ,omori1 ! mean radius ( propagation 0 ab\t #cbc miles1 & ! total di/urb$ area mu/ !re=e h be5 ab\t #ccj1jjj squ>e miles1 or ne>ly f\r times ! area ( ,great ,brita94 ,consid]+ ! extraord9>y int5sity ( ! %ock 9 ! c5tral di/rict1 ?is c h>dly be reg>d$ z an ov]-e/imate4 ,! isoseismal l9es %[n 9 ,fig4 #da are n to be reg>d$ z drawn ) great accuracy2 = !re is no m>k$ sep>ation betwe5 ! te/s correspond+ to ! diff]5t degrees ( ! scale ( int5sity4 ,! seismographs at ,gifu & ,nagoya 7 ?r[n d[n )9 ! fir/ few seconds1 & fail$ to record ! pr9cipal motion4 ,b a great numb] ( well-=m$ /one lant]ns & tomb/ones 7 ov]turn$1 &1 f ! dim5sions ( ^!1 ,pr(essor ,omori calculat$ ! maximum horizontal accel]ation necess>y = ov]turn+ !m at fifty-n9e places )9 ! meizoseismal area4#ee ,at five ( ^! x exce$$ #djjj millimetres p] second p] second1 an accel]ation equal to ab\t five-twelf?s ( t due to gravity4 ,mak+ use ( ^! obs]vations1 ,pr(essor ,omori has drawn two isoseismal l9es )9 ! c5tral di/rict1 :i* are %[n 9 ,fig4 #dd4 ,at e po9t ( ! curve m>k$ #b1 ! maximum accel]ation 0 #bjjj millimetres p] second p] second1 & ( t m>k$ #a1 #hjj millimetres p] second p] second4 ,! dott$ l9e )9 ! curve m>k$ #b repres5ts ! b\nd>y ( ! meizoseismal area1 :i*1 x w be obs]v$1 diff]s slightly f t giv5 by ,pr(essor ,koto 7see ,fig4 #de74 ,! diff]5ce1 h[ev]1 is app>5tly due to ! /&>d ( int5sity adopt$1 ,pr(essor ,koto's b\nd>y agree+ r closely ) ! curve m>k$ #b 9 ,fig4 #dd4 ,,nature ,,( ,,! ,,%ock4 ,little has yet be5 made kn[n ) reg>d to ! nature ( ! %ock1 & ! publi%$ records ( ! accompany+ s\nd are s r>e t x seems z a rule to h pass$ unhe>d4 ,! seismographs at ,gifu & ,nagoya regi/]$ ! fir/ half-doz5 vibrations1 & 7 !n buri$ b5ea? ! fall5 build+s4 ,9 ! foll[+ table1 ! data f ^! two /ations are !re=e incomplete3-- ,,pr9cipal ,,measurem5ts ,,obta9$ ,,f ,,seismographic ,,records4 ---------------------------------------- -------------------------- ,tokio ,gifu4 ,nagoya4 ,osaka4 7,imp4 ,univ474 ---------------------------------------- -------------------------- ,maximum horizontal motion #ah mm4 #bf mm4 #cj mm4 #ce mm4 ,p]iod ( ditto #b4j secs4 #a4c sec4 #a4j sec4 #b4j secs4 ,maximum v]tical motion #aa4c mm4 #f4b mm4 #h mm4 #i4e mm4 ,p]iod ( ditto #j4i sec4 #a4e sec4 #a4j sec4 #b4d secs4 ---------------------------------------- -------------------------- ,if ! p]iod ( ! pr9cipal vibrations 7 kn[n1 ! obs]vations ( ,pr(essor ,omori on ! ov]turn+ ( bodies w\ld enable u to det]m9e ! range ( motion at diff]5t places4 ,= in/ance1 ! maximum accel]ation at ,nagoya 0 f\nd by ^! obs]vations to be #b1fjj millimetres p] second p] second1 & if we take ! p]iod ( ! greate/ horizontal motion to be ! same z t ( ! initial vibrations--namely1 #a4c second1 ! total range 7or d\ble amplitude7 w\ld be #bbc millimetres1 or #h4h in*es4 ,) ! same p]iod1 & ! maximum accel]ation obs]v$ 7at ,iwakura & ,konaki7 ( m ?an #d1cjj millimetres p] second p] second1 ! total range w\ld be great] ?an #ad4e in*es4#ef ,9 ! meizoseismal area1 _m p]sons saw waves cross+ ! surface ( ! gr\nd4 ,at ,akasaka1 accord+ to "o witness1 ! waves came d[n ! /reets 9 l9es1 _! height be+ p]haps "o foot1 & _! l5g? betwe5 t5 & ?irty feet4 ,to ! nor? ( ! same area1 we are told t ! %orel9e rose & fell1 & ) ?is ris+ & fall+ ! wat]s rec$$ & advanc$4 ,ev5 at ,tokio1 :i* is ab\t #age miles f ! epic5tre1 ! tilt+ ( ! gr\nd 0 v noticeable4 ,aft] wat*+ 8 seismographs = ab\t two m9utes1 ,pr(essor ,milne next obs]v$ ! wat] 9 an adjo9+ tank1 #hj feet long & #bh feet wide1 ) ne>ly v]tical sides4 ,at ! "t x 0 hold+ ab\t #ag feet ( wat]1 :i* 0 runn+ across its bread?1 ris+ fir/ on "o side & !n on ! o!r to a height ( ab\t two feet4 ,/ill cle>] is ! evid5ce ( ! seismographs 9 ! same city4 ,in/ead ( a numb] ( irregul> waves1 all ! records %[ a s]ies ( clean-cut curves4 ,! heavy masses 9 ! horizontal p5dulums 7 tilt$ in/ead ( rema9+ z /eady po9ts4 ,!y 7 n simply sw++1 = ! p]iod ( ! undulations diff]$ f t ( ! seismograph :5 set sw++1 & also v>i$ 9 successive undulations4 ,x 0 asc]ta9$ aft]w>ds1 by measurem5t ) a level1 t to produce ^! deflections1 ! seismograph mu/ h be5 tilt$ ?r\gh an angle ( ab\t "o-?ird ( a degree4 ,direction ( ! ,%ock4--,%ortly aft] ! e>?quake1 ,pr(essor ,omori travell$ ov] ! meizoseismal area & made a l>ge numb] ( obs]vations on ! directions 9 :i* bodies 7 ov]turn$1 tak+ c>e to include only ^? 9 :i* ! direction ( fall+ w\ld n be influ5c$ by ! =m ( ! base1 su* z ! cyl9drical /one lant]ns s frequ5tly f\nd 9 ,japanese g>d5s4 ,at "s places ^! bodies fell 9 v>i\s directions1 at o!rs ) consid]able uni=mity 9 "o direction4 ,= in/ance1 at ,nagoya1 out ( #bjj /one lant]ns ) cyl9drical /ems1 #aai fell betwe5 we/ & s\?1 & #cf betwe5 ea/ & nor?2 ! numb]s fall+ )9 successive angles ( #ae be+ repres5t$ 9 ,fig4 #dc4 ,! mean direction ( fall is ,w4 #cj ,s41 co9cid+ ) t 9 :i* ! majority ( ! lant]ns 7 ov]turn$4 ,simil> obs]vations 7 made at =ty-two o!r places )9 & ne> ! meizoseismal area1 & ! result+ mean direction = ea* su* place 9 ! ,m9o-,ow>i di/rict is %[n by %ort l9es 9 ,fig4 #dd1 ! arr[ indicat+ ! direction t[>ds :i* ! majority ( bodies at a giv5 place 7 ov]turn$4 ,x w be se5 f ?is map t ! direction ( ! e>?quake motion 0 g5]ally at "r angles1 or ne>ly s1 to t ( ! neighb\r+ "p ( ! meizoseismal zone1 & t on bo? sides ( x1 ! majority ( ov]turn$ bodies at ea* place fell t[>ds ?is zone4 ,illu/ration3 ,,fig4 #dc4--,plan ( ,directions ( ,fall ( ,ov]turn$ ,bodies at ,nagoya4 ,illu/ration3 ,,fig4 #dd4--,map ( ,mean ,directions ( ,%ock & ,isoseismal ,l9es 9 ,c5tral ,di/rict4 7,omori47 ,,velocity ,,( ,,! ,,e>?-,,waves4 ,! times ( ! great e>?quake & ( sixte5 m9or %ocks on ,octob] #bh? & #bi? & ,novemb] #f? 7 det]m9$ at ! ,c5tral ,meteorological ,obs]vatory at ,tokio1 & at ei!r two or ?ree ( ! obs]vatories ( ,gifu1 ,nagoya1 & ,osaka1 ea* ( :i* is provid$ ) a seismograph & *ronomet]4 ,! aft]-%ocks ref]r$ to orig9at$ ne> a po9t ab\t #f miles we/ ( ,gifu1 & ! diff]5ce betwe5 ! di/ances ( ,tokio & ,osaka f ?is po9t is #hi-a_/b miles1 ( ,tokio & ,nagoya #adg miles1 & ( ,tokio & ,gifu #afe miles4 ,! mean "t-int]vals betwe5 ^! ?ree pairs ( places 7 #fg1 #aaa1 & #abh seconds respectively2 & ^! give = ! mean velocity = ea* int]val #b4a kilometres 7or #a4c mile7 p] second4 ,?us !re appe>s 9 ^! cases to be no s5sible v>iation 9 ! velocity ) ! di/ance f ! orig94 ,z might be expect$1 an e>?quake ( su* sev]ity 0 record$ by magnetomet]s at sev]al di/ant obs]vatories4 ,di/urbances on ! regi/]s ( ,zikawei 7,*9a71 ,mauritius1 ,utre*t1 & ,gre5wi* h be5 attribut$ to ! ,japanese e>?quake1 b ! times at :i* !y comm5c$ are too indef9ite to all[ ( any det]m9ation ( ! surface-velocity ( ! e>?-waves to great di/ances f ! orig94 ,,! ,,great ,,fault-,,sc>p4 ,z 9 all disa/r\s e>?quakes1 ! surface ( ! gr\nd 0 sc>r$ & r5t by ! %ock4 ,f ! hillsides great l&slips desc5d$1 fill+ ! valleys ) dbris2 & slopes :i* 7 =m]ly gre5 ) =e/1 aft] ! e>?quake look$ z if !y _h be5 pa9t$ yell[i%-:ite4 ,innum]able fissures cut up ! pla9s1 ! g5]al appe>ance ( ! gr\nd1 accord+ to ,pr(essor ,milne1 be+ z if gigantic pl\ghs1 ea* cutt+ a tr5* f #c to #ab feet deep1 _h be5 dragg$ up & d[n ! riv]-banks4 ,b by f> ! mo/ rem>kable feature ( ! e>?quake 0 a great r5t or fault1 :i*1 unlike ! fissures j ref]r$ to1 pursu$ its c\rse reg>dless ( valley1 pla91 or m\nta94 ,al?\gh at fir/ sight q insignificant 9 _m places1 & "s "t h>dly visible to ! untra9$ eye1 ,pr(essor ,koto has succe$$ 9 trac+ ?is fault along ! surface = a di/ance ( =ty miles1 & he gives good reasons = believ+ t its total l5g? mu/ be n less ?an sev5ty miles4 ,illu/ration3 ,,fig4 #de4--,map ( ,meizoseismal ,area4 7,koto47 ,illu/ration3 ,,fig4 #df4--,pl\gh%>e ,appe>ance ( ! ,fault ne> ,fujitani4 7,koto47 ,illu/ration3 ,,fig4 #dg4--,! ,fault-sc>p at ,midori4 7,koto47 ,! g5]al "* ( ! fault-sc>p *anges ) ! surface features4 ,on flat gr\nd1 :]e ! ?r[ is small1 x cuts up ! s(t e>? into enorm\s clods1 or makes a r\nd$ ridge f "o to two feet high1 s t x resembles1 m ?an any?+ else1 ! pa?way ( a gigantic mole 7,fig4 #df74 ,:5 ! ?r[ is consid]able--& 9 "o place x rea*es f #ah to #bj feet--! fault-sc>p =ms a t]race1 :i* f a di/ance has ! appe>ance ( a railway embankm5t 7,fig4 #dg74 ,or1 aga91 :]e ! r5t trav]ses a m\nta9 ridge or a spur ( hills1 x caus$ ext5sive l&slips1 "o side ( x desc5d+ consid]ably 9 level1 c>ry+ ! =e/ ) x1 b ) ! trees complicat$ly int]lock$ or pro/rate on ! gr\nd4 ,illu/ration3 ,,fig4 #dh4--;,displacem5t ( ,field ,divisions by ! ,fault ne> ,ni%i-,katabira4 7,koto47 ,at its s\!rn end1 ! fault 0 se5 = ! fir/ "t cross+ a field ne> ! village ( ,katabira4 ,! field 0 brok5 into clods ( e>?1 & swoll5 up to a height ( #e-a_/b y>ds1 :ile a great l&slip _h desc5d$ into x f an adjo9+ hill4 ,a little f>!r to ! nor?-we/1 ! gr\nd 0 %>ply cut by ! fault1 ! nor?-ea/ side hav+ slightly subsid$ & at ! same "t be5 %ift$ horizontally ?r\gh a di/ance ( #c-a_/d to #d feet to ! nor?-we/ ,adjo9+ fields 7 =m]ly sep>at$ by /raight m\nds or ridges runn+ nor? & s\? & ea/ & we/1 & ^! m\nds 7 cut ?r\gh by ! fault & displac$1 z %[n 9 ,fig4 #dh4 ,f ?is po9t ! fault runs 9 a g5]al nor?-we/]ly direction1 ! nor?-ea/ side be+ always slightly l[]$ ) respect to ! o!r & %ift$ to ! nor?-we/4 ,ne> ,seki x takes a m we/]ly direction1 & cont9ues s to a %ort di/ance ea/ ( ,takatomi1 :]e ! nor? side is l[]$ by five feet1 & mov$ ab\t #a-a_/d feet to ! we/4 ,at ! nor? end ( ,takatomi1 a village 9 :i* e h\se 0 levell$ ) ! gr\nd1 ! fault is d\ble1 & ! cont9u\s l[]+ t[>ds ! nor? has conv]t$ a once level field into slop+ gr\nd4 ,at ?is po9t1 ! small riv] ,toba1 fl[+ s\?1 is p>tially block$ by ! fault-sc>p1 & an area ( ab\t ?ree-qu>t]s ( a squ>e mile1 on :i* two villages /&1 0 conv]t$ into a deep swamp 7,fig4 #di71 s t1 z ! e>?quake occurr$ at ! "t ( ! rice-h>ve/1 ! f>m]s 7 oblig$ to cut ! gra9 f boats4 ,aft] pass+ ,takatomi1 ! fault aga9 turns to ! we/-nor?-we/1 b1 ! ?r[ be+ small1 x resembles "h ! track ( an enorm\s mole4 ,at ,umh>a x crosses a g>d5 betwe5 two p]simmon trees1 appe>+ on ! h>d face ( ! gr\nd z a m]e l9e2 b ! trees1 :i* 7 be=e 9 an ea/-&-we/ l9e1 n[ /& 9 "o runn+ nor? & s\?1 )\t be+ 9 ! lea/ affect$ by ! movem5t 7,fig4 #ej74 ,f "h to ,kimb>a1 :]e ! fault ent]s ! ,neo valley1 ! nor? side is always depress$ & %ift$ we/w>ds by ab\t #f-a_/b feet4 ,illu/ration3 ,,fig4 #di4--,map ( ,swamp =m$ by /oppage ( ,riv] ,toba by ,fault-sc>p4 7,koto47 ,illu/ration3 ,,fig4 #ej4--,%ift+ ( ,trees by fault at ,umh>a4 7,koto47 ,x 0 9 ! ,neo valley t ! supreme ef=ts ( ! e>?quake 7 manife/$4 ,l&slips 7 s num]\s t ! great] "p ( ! m\nta9 slopes _h desc5d$ into ! valley1 ! :ole appe>ance ( :i* _h *ang$4 ,unfamili> ob/acles1 rem>ks ,pr(essor ,koto1 made !mselves app>5t1 & small hills cov]$ ) =e/ _h come into sight :i* _h n be5 se5 be=e4 ,b ! gr\nd 0 n only l[]$ & %ift$ by ! fault2 x 0 p]man5tly compress$1 plots orig9ally #dh feet 9 l5g? aft]w>ds measur+ only #cj feet4 ,9 fact1 x appe>s1 9 ! words ( ,pr(essor ,milne1 z if ! :ole ,neo valley _h become n>r[]4 ,a few miles aft] ent]+ ! ,neo valley1 ! ?r[ ( ! fault rea*es its maximum at ,midori4 ,b in/ead ( ! relative depression ( ! ea/ side1 :i* prevails ?r\gh\t ! re/ ( ! l9e1 t side is "h ab\t #bj feet high] ?an ! o!r4 ,x is1 h[ev]1 %ift$ z usual t[>ds ! nor?1 by ab\t #ac feet2 & ?is displacem5t is r5d]$ especially evid5t by ! abrupt break 9 ! l9e ( a new road to ,gifu 7,fig4 #dg74 ,t ! ea/ side has really ris5 is cle>1 =1 a little high] up1 ! riv] has *ang$ f a %all[ rapid /ream #cj y>ds wide into a small lake ( m ?an twice ! wid?1 & s deep t a boatman's pole c\ld n rea* ! bottom4 ,at ,ita%o1 ab\t a mile nor? ( ,midori1 bo? sides are ne>ly on ! same level1 ! fault appe>+ l a mole's track2 & sev5 miles f>!r1 at ,nago%ima1 ! ea/ side is relatively depress$ by m ?an a y>d1 & at ! same "t %ift$ ab\t #f-a_/b feet to ! nor?4 ,illu/ration3 ,,fig4 #ea4--;,daily frequ5cy ( aft]-%ocks at ,gifu & ,nagoya4 ,at ,nogo1 ! ma9 ,neo valley turns (f at "r angles to ! ea/1 & ! fault cont9ues its c\rse up a side valley1 ! ea/ side1 ) respect to ! o!r1 be+ cont9ually depress$ & %ift$ t[>ds ! nor?4 ,x 0 trac$ by ,pr(essor ,koto ?r\gh ,fujitani 7,fig4 #df71 :]e !re 7 _m unmi/akable evid5ces ( ! viol5ce ( ! %ock1 z f> z ! ea/]n %\ld] ( ,haku-san2 & "h1 aft] foll[+ ! fault = #dj miles1 ! lat5ess ( ! season compell$ him to return4 ,!re c be no d\bt1 h[ev]1 t x runs z f> z ,m9omata2 & x is probable1 f ! l9e> ext5sion ( ! meizoseismal area1 t x does n entirely die out be=e rea*+ ! city ( ,fukui1 #gj miles f its />t+-po9t at ,katabira4 ,,m9or ,,%ocks4 ,= "s h\rs aft] ! e>?quake1 %ocks 7 s frequ5t 9 ! meizoseismal area t ! gr\nd 9 places h>dly ev] ceas$ f trembl+4 ,)\t in/rum5tal aid1 detail$ record 0 ( c\rse impossible2 b =tunately ! buri$ seismographs at ,gifu & ,nagoya 7 un9jur$1 & 9 ab\t sev5 h\rs bo? 7 once m 9 work+ ord]4 ,to ! en]gy by :i* ?is result 0 accompli%$1 we owe our mo/ valuable regi/]s ( ! aft]-%ocks ( a great e>?quake4 ,illu/ration3 ,,fig4 #eb4--,mon?ly frequ5cy ( aft]-%ocks at ,gifu4 7,omori47 ,until ! end ( #ahic--t is1 9 little m ?an two ye>s--! total numb] ( %ocks record$ at ,gifu 0 #c1cfe1 & at ,nagoya #a1bih4 ,none ( ^! approa*$ ! pr9cipal e>?quake 9 sev]ity4 ,nev]!less1 ( ! ,gifu s]ies1 #aj 7 describ$ z viol5t & #ig /rong2 :ile ( ! rema9d]1 #a1hjh 7 weak1 #a1jda feeble1 & #dji 7 s\nds alone )\t any accompany+ %ock4 ,! slight int5sity ( mo/ ( ! %ocks is also evid5t f ! inequality 9 ! numb]s record$ at ,gifu & ,nagoya1 f :i* x appe>s t ne>ly two-?irds 7 imp]ceptible m ?an ab\t #be miles f ! *ief orig9 ( ! %ocks4 ,only #gj ( ! aft]-%ocks dur+ ! fir/ two ye>s 7 regi/]$ at ,osaka1 & n m ?an #cj at ,tokio4 ,di/ribution ( ,aft]-%ocks 9 ,"t4--,! decl9e 9 frequ5cy ( ! aft]-%ocks 0 at fir/ extremely rapid1 ! numb]s record$ at ,gifu dur+ ! six days aft] ! e>?quake be+ #cjc1 #adg1 #aaf1 #ii1 #ib1 & #ha1 & at ,nagoya #ahe1 #ic1 #gi1 #ef1 #cj1 & #ca2 9 fact1 half ( ! %ocks up to ! end ( #ahic occurr$ by ,novemb] #bcrd at ,gifu1 & by ,novemb] #f? at ,nagoya4 ,! daily numb]s at ^! two places are repres5t$ 9 ,fig4 #ea1 9 :i* ! crosses correspond to ! numb]s at ,gifu1 & ! dots to ^? at ,nagoya2 & ! curves drawn ?r\gh or ne> ! m>ks repres5t ! av]age daily numb] ( %ocks f ,octob] #bi? to ,novemb] #bj?4 ,x w be se5 t ^! curves are hyp]bolic 9 =m1 ! *ange f v rapid to v gradual decl9e 9 frequ5cy tak+ place f five to t5 days aft] ! great e>?quake4 ,fig4 #eb illu/rates ! di/ribution 9 "t ( ! aft]-%ocks at ,gifu to ! end ( #ahic1 ! ord9ates 9 ^! cases repres5t+ ! numb] ( %ocks dur+ successive mon?s4#eg ,a simil> rapid & !n gradual decl9e 9 frequ5cy *>act]ises ! /rong & weak %ocks record$ at ,gifu4 ,( ! t5 viol5t %ocks1 only "o occurr$ aft] ! beg9n+ ( ,janu>y #ahib2 & ( ! #ig /rong %ocks1 only ?ree aft] ,april #ahib4 ,b at ! comm5cem5t ( ! s]ies1 feeble %ocks 7i4e41 %ocks t c\ld j be felt7 & e>?-s\nds )\t any accompany+ movem5t 7 comp>atively r>e1 & did n become really prom95t until two mon?s _h elaps$4 ,( ! #cjh aft]-%ocks record$ 9 #ahic1 none c\ld be describ$ z /rong1 only #aj 7 weak1 :ile #bfc 7 feeble %ocks & #ce m]ely e>?-s\nds4 ,! la/ two diagrams %[ at a glance t ! decl9e 9 frequ5cy ( aft]-%ocks is v f> f be+ uni=m4 ,"s ( ! fluctuations are due to ! occurr5ce ( exceptionally /rong %ocks1 ea* ( :i* is foll[$ by its own m9or tra9 ( aft]-%ocks4#eh ,o!rs seem to be p]iodic1 & possibly owe _! orig9 to ext]nal causes unconnect$ ) ! e>?quake4#ei ,me?od ( repres5t+ ! ,di/ribution ( ,aft]-%ocks 9 ,space4--,! maps 9 ,figs4 #ed-eg %[ ! di/ribution ( ! aft]-%ocks 9 space dur+ f\r successive int]vals ( two mon?s ea*4 ,!y are f\nd$ on ,pr(essor ,milne's great catalogue ( ,japanese e>?quakes1 :i* give1 among o!r data1 ! "t ( occurr5ce & ! position ( ! epic5tre = e %ock until ! end ( #ahib4 ,= ! latt] purpose1 ! :ole c\ntry is divid$ by nor?-s\? & ea/-we/ l9es into numb]$ rectangles1 ea* "o-six? ( a degree 9 l5g? & bread?2 & ! position ( an epic5tre is d5ot$ by ! numb] ( ! rectangle 9 :i* x occurs4 ,! area includ$ )9 ! maps is b\nd$ by ! p>allels #cd #dj' & #cf #bj' lat4 ,n41 & by ! m]idians #b #aj' & #c #ej' long4 ,w4 ( ,tokio1 s t t5 rectangles adjo9 ea* side ( ! map4 ,! numb] ( epic5tres ly+ )9 ea* rectangle hav+ be5 c\nt$1 curves are !n drawn ?r\gh ! c5tres ( all rectangles conta9+ ! same numb] ( epic5tres1 or ?r\gh po9ts :i* divide ! l9e jo9+ ! c5tres ( two rectangles 9 ! prop] proportion4 ,tak+1 = example1 ! curve m>k$ #e1 if ! numb]s 9 two consecutive rectangles are #c & #g1 ! curve bisects ! l9e jo9+ _! c5tres2 if ! numb]s are #a & #f1 ! l9e jo9+ _! c5tres is divid$ into five equal p>ts1 & ! curve passes ?r\gh ! fir/ po9t ( division reckon$ f ! c5tre ( ! rectangle 9 :i* six epic5tres are f\nd4 ,?us ! mean+ ( ! curve m>k$1 say1 #e may be /at$ z foll[s3--,if any po9t 9 ! curve be imag9$ z ! c5tre ( a rectangle ^: sides are direct$ nor?-s\? & ea/-we/1 & are respectively "o-six? ( a degree ( latitude & longitude 9 l5g?2 !n ! numb] ( epic5tres )9 ?is rectangle is at ! rate ( #e = ! "t consid]$4 ,prep>ation = ! ,great ,e>?quake4--,at fir/ sight1 !re appe>s to h be5 b little direct prep>ation = ! great e>?quake4 ,except = a r /rong %ock on ,octob] #be?1 at #i4ad ,p4,m41 x occurr$ )\t ! w>n+ ( any prelim9>y tremors4 ,b a clos] exam9ation ( ! evid5ce %[s1 z we %\ld inde$ expect1 t !re 0 a di/9ct increase 9 activity = _m mon?s be=eh&4 ,! region _h become seismically s5sitive4 ,( ! hundr$ rectangles includ$ 9 ! maps 9 ,figs4 #ec-eg1 !re are ?irte5 ly+ along ! meizoseismal area ( ! e>?quake ( #ahia1 9 :i* ne>ly all ! aft]-%ocks orig9at$4 ,dur+ ! five ye>s #ahhe-hi1 #ec out ( #abe e>?quakes 7or #db p] c5t47 _h _! epic5tres ly+ )9 ! ?irte5 rectangles2 or1 9 o!r words1 ! av]age frequ5cy 9 "o ( ! rectangles ( ! meizoseismal area 0 five times z great z 9 "o ( ^? outside x4 ,9 #ahij & #ahia 7until ,octob] #bg?71 ! p]c5tage 9 ! ?irte5 rectangles rose to #fa1 & ! av]age frequ5cy 9 "o ( !m to t5 times t ( "o ( ! ext]ior rectangles4 ,! curves 9 ,fig4 #ec illu/rate ! di/ribution ( epic5tres dur+ ! latt] int]val4 ,x w be se5 t !y foll[ r\ghly ! c\rse ( ! meizoseismal area s\?w>ds to ! ,sea ( ,is1 & t to ! s\?-ea/ !y cont9ue = sev]al miles ! %ort bran* ( ! meizoseismal area :i* surr\nds ! s\!rn end ( ! fault-sc>p4 ,illu/ration3 ,,fig4 #ec4--;,di/ribution ( prelim9>y ,%ocks 9 ,space4 7,davison47 ,?us1 ! prep>ation = ! great e>?quake is %[n1 fir/1 by ! increas$ frequ5cy ( e>?quakes orig9at+ )9 its meizoseismal area2 &1 secondly1 by ! uni=mity 9 ! di/ribution ( epic5tres ?r\gh\t ! same region1 ! m>k$ conc5tration ( ef=t :i* *>act]ises ! aft]-%ocks be+ h>dly p]ceptible dur+ ! ye>s #ahij-ia4 ,illu/ration3 ,,fig4 #ed4--;,di/ribution ( ,aft]-%ocks 9 ,space 7,novemb]-,decemb] #ahia74 7,davison74 ,di/ribution ( ,aft]-%ocks 9 ,space4--,we h se5 t ! aft]-%ocks 7 subject to a fluctuat+ decl9e 9 frequ5cy1 rapid at fir/1 & m gradual aft]w>ds4 ,x is evid5t1 f ,figs4 #ed-eg1 t a simil> law gov]ns ! area )9 :i* ! aft]-%ocks orig9at$4 ,dur+ ! fir/ two mon?s1 epic5tres occur ov] ne>ly ! :ole ( ! meizoseismal area1 b aft]w>ds !y are conf9$ to a small] di/rict1 :i* sl[ly1 ?\gh n cont9ually1 decreases 9 size4 ,illu/ration3 ,,fig4 #ee4--;,di/ribution ( ,aft]-%ocks 9 ,space 7,janu>y-,febru>y1 #ahib74 7,davison47 ,illu/ration3 ,,fig4 #ef4--;,di/ribution ( ,aft]-%ocks 9 ,space 7,m>*-,april74 7,davison47 ,! mo/ important feature 9 ! di/ribution ( ! epic5tres is ! c5tral region ( extraord9>y activity2 b !re are also di/ricts ( m9or & m %ort-liv$ activity ne> ! ?ree extremities ( ! meizoseismal b&4 ,! seat ( *ief seismic action %ifts slightly f "o "p to ano!r ( ! epic5tral region1 especially ab\t ! end ( #ahia1 z w be se5 by comp>+ ! inn]mo/ curves ( ,figs4 #ed & #ee4 ,?us1 ) ! decl9e 9 frequ5cy ( ! aft]-%ocks & ! decrease 9 _! sph]e ( action1 !re took place concurr5tly a gradual b oscillat+ )drawal ( t action to a m or less c5tral region ( ! fault4 ,illu/ration3 ,,fig4 #eg4--;,di/ribution ( ,aft]-%ocks 9 ,space 7,may-,june1 #ahib74 7,davison47 ,s\nd ,ph5om5a ( ,aft]-%ocks4--,:ile comp>atively few obs]v]s seem to h notic$ any noise ) ! pr9cipal e>?quake1 _m ( ! aft]-%ocks 7 accompani$ by s\nds4 ,pr(essor ,omori describes !m z belong+ to two types4 ,!y 7 ei!r ru%+ feeble noises l t ( w9d1 or l\d rumbl+ noises l ^? ( ?und]1 ! dis*>ge ( a gun1 or ! fall ( a heavy body4 ,9 ! ,neo valley1 s\nds ( ! second type 7 mo/ frequ5t & di/9ct1 b !y ei!r occurr$ )\t any %ock at all1 or ! att5dant tremor 0 v feeble2 :ile1 on ! o!r h&1 sev]e %>p %ocks 7 g5]ally unaccompani$ by di/9ctly audible s\nds4 ,x is rem>kable1 also1 t s\nds 7 less frequ5tly he>d ) ! e>ly ?an ) ! lat] aft]-%ocks4 ,9 ,novemb] #ahia1 ! p]c5tage ( audible %ocks 0 #ag1 & f ,decemb] to ! foll[+ ,april always lay betwe5 #aj & #ab4 ,9 ,may ! p]c5tage sudd5ly rose to #ci1 & until ! end ( #ahib 0 always great] ?an #cb1 :ile 9 ,novemb] #ahib1 x rose z high z #di4 ,?is1 ( c\rse1 agrees ) ,pr(essor ,omori's obs]vation t s\nds att5d$ feeble %ocks m (t5 ?an /rong ones4 ,! di/ribution ( ! audible aft]-%ocks 9 space is %[n 9 ,fig4 #eh4 ,^! curves are drawn 9 ! same way z ^? 9 ,figs4 #ec-eg1 b !y repres5t ! p]c5tages1 n ! actual numb]s1 ( %ocks accompani$ by s\nd4 ,x w be notic$ t all ?ree gr\ps ( curves lie along ! meizoseismal area1 or ! cont9uation ( ! s\?-ea/ bran*2 :ile ! axis ( ! pr9cipal gr\p ( curves lies to ! we/ ( ! c5tral regions 9 :i* mo/ aft]-%ocks orig9at$4 ,illu/ration3 ,,fig4 #eh4--;,di/ribution ( ,audible ,aft]-%ocks 9 ,space 7,novemb] #ahia-;,decemb] #ahib74 7,davison47 ,! explanation ( ^! peculi>ities is no d\bt connect$ ) ! comp>ative inability ( ! ,japanese p to p]ceive ! deep s\nds :i* 9 ,europe are always he>d ) e>?quake %ocks4 ,! s\nds are r>ely he>d by !m m ?an a few miles f ! epic5tre4#fj ,we may !re=e conclude t slight aft]-%ocks orig9at$ ne>] ! surface ?an /rong ones1 t ! mean dep? ( ! foci decreas$ ) ! lapse ( "t1 & t ! axes ( ! sy/ems ( curves 9 ,fig4 #eh m>k out approximately ! l9es ( ! gr[+ faults4 ,! sep>ation ( ! two we/]ly gr\ps ( curves appe>s to %[ t ! ma9 bran* ( ! meizoseismal area is connect$ ) a fault r\ghly p>allel to t trac$ by ,pr(essor ,koto1 b ( :i* no sc>p 7if x exi/$7 c\ld be readily di/+ui%$ among ! sup]ficial fissures produc$ by ! great %ock4 ,,effect ,,( ,,! ,,e>?quake ,,on ,,! ,,seismic ,,activity ,,( ,,! ,,adjo9+ ,,di/ricts4 ,s great & sudd5 a displacem5t z occurr$ along ! fault-sc>p c\ld h>dly take place )\t affect+ ! /ability ( adjo9+ regions ( ! e>?'s cru/1 & we %\ld naturally expect to f9d a di/9ct *ange 9 _! seismic activity %ortly aft] ,octob] #bh?4 ,9 ,fig4 #ei two su* regions are %[n1 b\nd$ by ! /raight dott$ l9es4 ,! di/rict 9 :i* ! pr9cipal e>?quake & its aft]-%ocks orig9at$ is enclos$ )9 ! undulat+ dott$ l9es4 ,! cont9u\s l9es inside all ?ree di/ricts are ! curves correspond+ to #aj & #e epic5tres = ! ye>s #ahhe-ib4 ,n f> f ! axes ( ! out] gr\ps ( curves !re are probably transv]se faults1 approximately p>allel to ! great fault-sc>p & ! ma9 bran* ( ! meizoseismal b&1 & di/ant f !m ab\t #de & #ee miles respectively4 ,illu/ration3 ,,fig4 #ei4--,map ( ,adjo9+ ,regions 9 :i* ,seismic ,activity 0 affect$ by ! ,great ,e>?quake4 7,davison47 ,9 ! di/rict repres5t$ 9 ! nor?-ea/ corn] ( ,fig4 #ei1 #bi e>?quakes orig9at$ betwe5 ,janu>y #a/1 #ahhe1 & ,octob] #bg?1 #ahia1 & #cj betwe5 ,octob] #bh?1 #ahia1 & ,decemb] #ca/1 #ahib1 #g ( ! latt] numb] occurr+ 9 ,novemb] #ahia4 ,9 ! s\?-we/ di/rict1 ! correspond+ figures be=e & aft] ! e>?quake are #bj & #cf1 #h ( ! latt] occurr+ 9 ,novemb] #ahia4 ,?us1 9 ! nor?-ea/ di/rict1 = e %ock 9 ! int]val be=e ! e>?quake !re 7 six 9 an equal "t aft]w>ds1 & at ! rate ( #aj dur+ ,novemb] #ahia2 & 9 ! s\?-we/ di/rict1 = e %ock be=e ! e>?quake !re 7 #aj aft]w>ds1 & at ! rate ( #af dur+ ,novemb] #ahia4 ,n[1 x is unlikely t ! gradual increase ( /ress %\ld be s ne>ly proportion$ ev]y:]e to ! prevail+ conditions ( resi/ance z to give rise to a m>k$ & practically simultane\s *ange 9 seismic activity ov] a l>ge area2 :]eas ! p>oxysmal occurr5ce ( a /rong e>?quake might alt] ! surr\nd+ conditions ) comp>ative rapidity1 & s induce a /ate ( seismic excitem5t 9 ! neighb\rhood4 ,x !re=e seems v probable t ! increas$ activity 9 ! two di/ricts "h describ$ 0 a direct consequ5ce ( ! occurr5ce ( ! great e>?quake4 ,,orig9 ,,( ,,! ,,e>?quake4 ,! prepond]ance ( prelim9>y e>?quakes )9 ! meizoseismal area & ! outl9+ ( ! fault-sy/em by ! frequ5cy curves ( #ahij-ia 7,fig4 #ec7 po9t to ! previ\s exi/5ce ( ! orig9at+ fault or faults1 & to ! e>?quake be+ due1 n to ! =mation ( a new fracture1 z has be5 sugge/$1 b to ! gr[? ( an old fault4 ,! la/ sev]e e>?quake 9 ! ,m9o-,ow>i pla9 occurr$ 9 #ahei1 s t = m ?an ?irty ye>s !re _h be5 b little relief to ! gradually increas+ /resses4 ,n[1 ! di/ribution ( /ress mu/ h be5 f> f uni=m ?r\gh\t ! fault-sy/em1 & also ! resi/ance to displacem5t f> f proportional to ! /resses at diff]5t places4 ,at c]ta9 po9ts1 !re=e1 ! effective /ress w\ld be great] ?an else:]e1 & x w\ld be at ^! po9ts t fault-slips w\ld fir/ occur4 ,su* slips t5d to remove ! inequalities 9 effective /ress4 ,?us1 ! function ( ! slight %ocks ( #ahij & #ahia 01 briefly1 to equalise ! effective /ress ov] ! :ole fault-sy/em1 & s to cle> ! way = "o or m great slips ?r\gh\t its entire l5g?4 ,z to :i* side ( ! fault mov$ dur+ ! great displacem5t1 or :e!r bo? sides mov$ at once1 we h no direct evid5ce b z reg>ds ! neighb\rhood ( ,midori1 & !re ! conditions 7 exceptional4 ,pr(essor ,koto ?9ks t x 0 probably ! rock on ! nor?-ea/ side t 0 g5]ally depress$ & always %ift$ to ! nor?-we/ ,b ! di/urbance 9 reality seems to h be5 m complicat$4 ,t ?is 0 ! case1 t displacem5t occurr$ along m ?an "o fault1 is probable f ! bran*+ ( ! meizoseismal area1 ! isolation ( ! audibility curves ( ! aft]-%ocks 7,fig4 #eh71 & ! sudd5 increase 9 seismic activity bo? to ! nor?-ea/ & s\?-we/ ( ! epic5tre4 ,! deta*$ portion ( ! meizoseismal area ne> ,lake ,biwa may also po9t to a sep>ate focus4 ,! :ole region1 inde$1 0 evid5tly subject$ to int5se /resses1 & ! depression on ! nor?-ea/ side ( ! fault-sc>p c h>dly fail to h be5 accompani$ by o!r movem5ts1 especially along a fault runn+ ne> ! we/]n m>g9 ( ! ma9 bran* ( ! meizoseismal area4 ,! lat] /ages ( ! movem5ts are some:at cle>]4 ,f a /udy ( ! aft]-%ocks1 we le>n t ! di/urb$ masses began at once to settle back t[>ds ! position ( equilibrium4 ,at fir/ ! slips 7 num]\s & took place ov] ! :ole fault-sy/em1 b *iefly at a consid]able dep?1 :]e no d\bt ! initial displacem5t 0 greate/4 ,aft] a few mon?s1 /ability 0 ne>ly re/or$ along ! extremities ( ! faults2 slips 7 conf9$ almo/ entirely to ! c5tral regions1 :ile a mu* l>g] proportion ( !m took place )9 ! sup]ficial portions ( ! faults4 ,! (ficial records br+ d[n ! hi/ory to ! end ( #ahic4 ,s9ce t "t m ?an "o /rong %ock has be5 felt 9 ! ,m9o-,ow>i pla92 b ! /age ( recov]y f ! di/urbances ( #ahia is probably ne> its end1 & we seem r to be ent]+ on a p]iod 9 :i* ! =ces are once m sil5tly ga!r+ t soon] or lat] w result 9 ano!r great cata/rophe4 ,,ref]5ces4 #a4 ,,cond]1 ,j4--,an ,ar*itect's ,notes on ! ,great ,e>?quake ( ,octob] #ahia4 ,japan ,seismol4 ,j\rn41 vol4 ii41 #ahic1 pp4 #a-ia4 #b4 ,,davison1 ,c4--,on ! ,di/ribution 9 ,space ( ! ,accessory ,%ocks ( ! ,great ,japanese ,e>?quake ( #ahia4 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 liii41 #ahig1 pp4 #a-ae4 #c4 ---- ,on ! ,effect ( ! ,great ,japanese ,e>?quake ( #ahia on ! ,seismic ,activity ( ! ,adjo9+ ,di/ricts4 ,geol4 ,mag41 vol4 iv41 #ahig1 pp4 #bc-bg4 #d4 ---- ,on ! ,diurnal ,p]iodicity ( ,e>?quakes4 ,phil4 ,mag41 vol4 xiii41 #ahif1 pp4 #dfc-dgf1 especially pp4 #dff-dfh4 #e4 ---- ,on ,e>?quake-,s\nds4 ,phil4 ,mag41 vol4 xlix41 #aijj1 pp4 #ca-gj--;especially pp4 #di-ec1 #fj-fa4 #f4 ,,koto1 ,b4--,! ,cause ( ! ,great ,e>?quake 9 ,c5tral ,japan1 #ahia4 ,j\rn4 ,coll4 ,sci4 ,imp4 ,univ4 ,japan1 vol4 v41 #ahic1 pp4 #bie-cec4 #g4 ,,masato1 ,h4--,report on ,e>?quake ,obs]vations 9 ,japan4 ,c5t4 ,meteor4 ,obs4 ( ,japan 7,tokio1 #ahib71 pp4 #af-ah1 #da1 & map #cj4 #h4 ,,milne1 ,j4--,a ,note on ! ,great ,e>?quake ( ,octob] #bh?1 #ahia4 ,japan ,seismol4 ,j\rn41 vol4 i41 #ahic1 pp4 #abg-aea2 ,brit4 ,assoc4 ,rep41 #ahib1 pp4 #aad-abh4 #i4 ---- ,a ,catalogue ( #h1cca ,e>?quakes record$ 9 ,japan betwe5 #ahhe & #ahib4 ,japan ,seismol4 ,j\rn41 vol4 iv41 #ahie1 pp4 #a-cfg--;especially pp4 #acd-bcd1 #cjc-cec4 #aj4 ---- ,on ,c]ta9 ,di/urbances 9 ! ,records ( ,magnetomet]s & ! ,occurr5ce ( ,e>?quakes4 ,brit4 ,assoc4 ,rep41 #ahih1 pp4 #bbf-bea--;especially pp4 #bbg1 #bcb1 #bcd1 #bda1 & #bde4 #aa4 ,,milne1 ,j41 & ,w4,k4 ,,burton4--,! ,great ,e>?quake 9 ,japan4 ,j\rn4 ,coll4 ,sci4 ,imp4 ,univ4 ,japan1 vol4 v41 #ahic1 pp4 #bie-ceb4 #ab4 ,,omori1 ,f4--,on ! ,aft]-%ocks ( ,e>?quakes4 ,j\rn4 ,coll4 ,sci4 ,imp4 ,univ4 ,japan1 vol4 vii41 #ahid1 pp4 #aaa-bjj2 ab/ract 9 ,japan ,seismol4 ,j\rn41 vol4 iii41 #ahid1 pp4 #ga-hj4 #ac4 ---- ,a ,note on ! ,great ,m9o-,ow>i ,e>?quake ( ,octob] #bh?1 #ahia4 ,pub4 ,e>?quakes ,inves4 ,com4 9 ,=eign ,languages1 ,no4 #d1 ,tokio1 #aijj1 pp4 #ac-bd4 #ad4 ---- ,sulla velocit di propagazione e sulla lunghezza delle onde sismi*e4 ,ital4 ,soc4 ,sismol4 ,boll41 vol4 i41 #ahie1 pp4 #eb-fj--;especially pp4 #eb-eg4 #ae4 ---- ,sull' int5sit e sull' ampiezza del movim5to nel gran t]remoto giapponese del #bh ottobre #ahia4 ,ital4 ,soc4 ,sismol4 ,boll41 vol4 ii41 #ahif1 pp4 #ahi-bjj4 #af4 ---- ,note on ! ,aft]-%ocks ( ! ,m9o-,ow>i ,e>?quake ( ,oct4 #bh?1 #ahia4 ,pub4 ,e>?quakes ,inves4 ,com4 9 ,=eign ,languages1 ,no4 #g1 ,tokio1 #aijb1 pp4 #bg-cb4 #ag4 ---- ,note on ! relation betwe5 ,e>?quake ,frequ5cy & ! ,atmosph]ic ,pressure4 ,tokyo ,phys4-,ma?4 ,soc4 ,reports1 vol4 ii41 #aijd1 ,no4 #h4 #ah4 ,,tanakadate1 ,a41 & ,h4 ,,nagaoka4 ,! ,di/urbance ( ,isomagnetics att5d+ ! ,m9o-,ow>i ,e>?quake ( #ahia4 ,j\rn4 ,coll4 ,sci4 ,imp4 ,univ4 ,japan1 vol4 v41 #ahic1 pp4 #adi-aib4 ,,footnotes3 #ed ,i h n ref]r$ to ! results ( ?is survey1 =1 ?\gh *anges 9 all ! magnetic elem5ts 7especially 9 horizontal int5sity7 h tak5 place betwe5 #ahhg & #ahia-ib1 ^! *anges _c be ascrib$ ) confid5ce to ! e>?quake 9 ! abs5ce ( a ?or\gh k ( ! secul> v>iation4 #ee ,f ! =mula ax99g_/y1 :]e a is ! maximum horizontal accel]ation1 g ! accel]ation due to gravity1 y ! height ( ! c5tre ( gravity1 & x its horizontal di/ance f ! edge ab\t :i* ! body 0 ov]turn$4 #ef ,^! e/imates are made1 on ! supposition ( simple h>monic motion1 f ! =mula #b99;aalpha99t#b_/7b99pi#b71 :]e #b;a is ! total range or d\ble amplitude1 a ! maximum accel]ation1 & t ! p]iod ( ! vibration4 #eg ,pr(essor ,omori f9ds t ! mean daily numb] ( e>?quakes y dur+ ! mon? x 7reckon$ f ,novemb] #ahia7 may be approximately repres5t$ by ! equation-- y #af4i _/ 7x #j4cig72 or1 tak+ ! semi-daily e>?quake numb]s dur+ ! five days betwe5 ,octob] #bi? & ,novemb] #bnd1 #ahia1 by ! equation-- y #ddj4g _/ 7x #b4cad71 :]e y d5otes ! numb] ( e>?quakes obs]v$ dur+ ! twelve h\rs d5ot$ by x1 ! "t be+ measur$ f ! fir/ half ( ,octob] #bi?4 ,x is int]e/+ to notice t1 tak+ acc\nt ( ! mean annual frequ5cy ( e>?quakes 9 ord9>y ye>s1 ! numb] ( %ocks obs]v$ at ,gifu dur+ ! two ye>s #ahih-ii %\ld1 accord+ to ! latt] =mula1 be #afc2 ! actual numb] record$ 0 #afj4 #eh ,! la/ viol5t %ock be=e ! end ( #ahic occurr$ on ,septemb] #g?1 #ahib1 & its effects on ! frequ5cy ( aft]-%ocks is %[n by ! daily numb]s record$ at ,gifu dur+ ! fir/ =tnight 9 ,septemb]4 ,^! are--#b1 #b1 #b1 #c1 #e1 #e1 #bh 7on ,septemb] #g?71 #h1 #h1 #e1 #d1 #c1 #b1 #d1 #c4 #ei ,! p]iodicity ( aft]-%ocks is discuss$ 9 ! pap]s numb]$ #d1 #ab1 #af1 & #ag at ! end ( ?is *apt]4 ,9 ^!1 ! exi/5ce ( diurnal & o!r p]iods is cle>ly e/abli%$4 ,pr(essor ,omori also %[s t ! mean daily b>ometric pressure is subject to fluctuations ) maxima occurr+ on an av]age e #e-a_/b days1 & t e>?quakes are lea/ frequ5t on ! days ( ! b>ometric maxima & m9ima1 & m frequ5t 9 ! days imm$iately prec$+ & foll[+ !m4 #fj ,( ! ,japanese e>?quakes ( #ahhe-ib orig9at+ b5ea? ! l&1 tw5ty-six p] c5t4 7 accompani$ by a record$ s\nd2 b less ?an "o p] c5t4 ( ^? orig9at+ b5ea? ! sea & n m ?an t5 miles f ! coa/4 ,,*apt] ,,viii4 ,,! ,,h]e=d ,,e>?quake ,,( ,,decemb] #ag,,?1 #ahif1 ,,& ,,! ,,inv]ness ,,e>?quake ,,( ,,septemb] #ah,,?1 #aija4 ,among ! e>?quakes describ$ 9 ?is volume1 ! ,h]e=d & ,inv]ness e>?quakes hold b a m9or place4 ,! damage to build+s1 ?\gh unusual = ?is c\ntry1 0 slight :5 comp>$ ) t caus$ by ! prec$+ %ocks2 !re 0 no loss ( life1 n a s+le p]son 0 injur$ by fall+ masonry4 ,! int]e/ ( ! e>?quakes lies entirely 9 ! detail$ /udy r5d]$ possible by num]\s obs]vations ( ! %ock & s\nd1#fa & 9 ! be>+ ( ?is evid5ce on ! g5]al !ory ( ! orig9 ( e>?quakes4 ,,! ,,h]e=d ,,e>?quake ,,( ,,decemb] #ag,,?1 #ahif4 ,! pr9cipal e>?quake ( ?is s]ies occurr$ at #e4cb ,a4,m4 on ,decemb] #ag?1 & 0 prec$$ by at lea/ n9e m9or %ocks 7! fir/ ( :i* 0 felt at ab\t #aa or #aa4cj ,p4,m4 on ,decemb] #af?71 & foll[$ by two o!rs on ! same day1 & by a ?ird & la/ on ,july #ai?1 #ahig4 ,! acc\nts ( ^! prelim9>y movem5ts w be f\nd on a lat] page1 z _! be>+ w be m fully app>5t aft] ! discussion ( ! pr9cipal %ock4 ,illu/ration3 ,,fig4 #fj4--;,isoseismal & ,isac\/ic l9es ( ,h]e=d e>?quake4 7,davison47 ,,isoseismal ,,l9es ,,& ,,di/urb$ ,,area4 ,on ! map 9 ,fig4 #fj1 ! cont9u\s curves repres5t isoseismal l9es correspond+ to ! degrees #h1 #g1 #f1 #e1 & #d ( ! ,rossi-,=el scale4 ,! isoseismal #h1 :i* is ! mo/ accurately drawn ( ! s]ies1 is an elongat$ oval1 #dj miles long1 #bc miles broad1 & conta9+ an area ( #gbd squ>e miles4 ,! long] axis is direct$ ,w4 #dd ,n4 & ,e4 #dd ,s4 ,)9 ?is curve1 !re are #gc places :]e build+s are kn[n to h be5 damag$1 #ee places be+ 9 ,h]e=d%ire1 #ag 9 ,gl\ce/]%ire1 & "o 9 ,worce/]%ire4 ,! mo/ important damage occurr$ 9 ! city ( ,h]e=d1 :i*1 9 #aija1 conta9$ #d1efe inhabit$ h\ses4 ,"h1 no few] ?an #bah *imneys _h to be repair$ or rebuilt4 ,! ,ca!dral 0 slightly injur$4 ,! f9ial ( a p9nacle ( ! ,lady ,*apel 0 ?r[n d[n1 a fragm5t ( a /one fell f "o ( ! ar*es 9 ! s\? transept1 & ! ?ree p9nacles ( ! we/]n front 7 fractur$4 ,sev]al *ur*es suff]$ to a simil> ext5t1 :ile1 at ! ,midl& ,railway ,/ation1 all ! sev5 *imney-/acks 7 %att]$4 ,at ,d9$or1 ,f[nhope1 ,dorm+ton1 ,)+ton1 & a few o!r villages1 ! damage 0 also relatively great] ?an else:]e1 ^! places all ly+ )9 a small oval ab\t #h-a_/b miles long1 :i* surr\nds1 n ! c5tre1 b r ! nor?-we/ focus1 ( ! isoseismal #h4 ,! isoseismal #g1 :i* includes places :]e ! %ock 0 /rong en\gh to ov]?r[ ornam5ts1 vases1 etc41 is also v ne>ly an ellipse1 ^: axes are #hj & #ef miles 9 l5g?1 & ^: area is #c1ehj squ>e miles4 ,its long] axis1 runn+ f ,w4 #db ,n4 to ,e4 #db ,s41 is practically p>allel to t ( ! inn] curve4 ,next 9 succession comes ! isoseismal #f1 surr\nd+ ^? places :]e ! %ock 0 /rong en\gh to make *&eli]s1 pictures1 etc41 sw+2 b1 z mo/ ( ! obs]v]s seem to h slept 9 d>k5$ rooms1 ! numb] ( det]m9+ po9ts = ?is curve is less ?an usual1 & its c\rse is !re=e laid d[n ) a some:at inf]ior degree ( accuracy4 ,! error1 h[ev]1 is probably small1 & we may !re=e reg>d ! isoseismal #f z ano!r ellipse1 #ada miles long1 #aaf miles broad1 & conta9+ an area ( #ac1jjj squ>e miles4 ,its long] axis is aga9 ne>ly p>allel to ^? ( ! prec$+ isoseismals4 ,! next two isoseismals are ne>ly circul> 9 =m4 ,x w be notic$ t l>ge portions ( !m1 & especially ( ! isoseismal #d1 trav]se ! sea4 ,9 ^! p>ts1 ! pa?s ( ! curves are to "s ext5t conjectural4 ,9 draw+ !m1 ! *ief guides are _! tr5d be=e leav+ ! l& & ! kn[n int5sity along ! neighb\r+ coa/l9es4 ,! isoseismal #e b\nds ! area )9 :i* ! %ock 0 p]ceptible z a s5sible displacem5t & n m]ely a quiv]4 ,its dim5sions are #bcc miles f nor?-we/ to s\?-ea/1 & #bbi miles f s\?-we/ to nor?-ea/1 & its area #da1afj squ>e miles4 ,! isoseismal #d1 :i* includes places :]e ! %ock 0 /rong en\gh to make doors1 w9d[s1 etc41 rattle1 is #cef miles f nor?-we/ to s\?-ea/1 & #ceg miles f s\?-we/ to nor?-ea/1 & #ih1jjj squ>e miles 9 area2 its c5tre co9cides ne>ly ) t ( ! small oval area 9 ! neighb\rhood ( ,h]e=d1 :]e ! damage to build+s 0 relatively great] ?an else:]e4 ,outside ! isoseismal #d1 ! e>?quake 0 obs]v$ at sev]al places4 ,! %ock 0 c]ta9ly felt at ,middlesbr\gh1 #ab-a_/b miles f ! curve1 & probably at ,kille%&ra 79 ,irel&71 #fe miles di/ant4 ,?us1 if we consid] ! b\nd>y ( ! di/urb$ area to co9cide ) ! isoseismal #d1 its area w\ld be #ih1jjj squ>e miles1 or #a-b_/c t ( ,engl& & ,wales2 if x 7 a circle conc5tric ) ! isoseismal #d1 & pass+ ?r\gh ,middlesbr\gh1 its area w\ld be #aae1jjj squ>e miles1 or ne>ly twice t ( ,engl& & ,wales2 :ile1 if x pass$ ?r\gh ,kille%&ra1 its area w\ld be #ahe1jjj squ>e miles1 or m ?an ?ree times ! area ( ,engl& & ,wales4#fb ,position ( ! ,orig9at+ ,fault4--,! =m1 directions1 & relative positions ( ! isoseismal l9es furni% important evid5ce ) reg>d to ! orig9at+ fault4 ,we conclude 9 ! fir/ place t its mean direction is p>allel to ! long] axes ( ! ?ree inn]mo/ isoseismal l9es--t is1 nor?-we/ & s\?-ea/1 or1 m accurately1 ,w4 #dc ,n4 & ,e4 #dc ,s4#fc ,9 ?is case1 ! elongat$ =ms ( ! isoseismal l9es _c be attribut$ to v>iations 9 ! nature ( ! surface rocks4 ,! di/rict embrac$ conta9s ab\t #ac1jjj squ>e miles1 & x is improbable t ! axes ( ! ?ree isoseismals %\ld reta9 _! p>allelism ov] s l>ge an area1 if ^! v>iations _h any consid]able effect4 ,moreov]1 9 ! same di/rict1 an e>?quake occurr$ 9 #ahfc1 ^: meizoseismal area 0 elongat$ f nor?-ea/ to s\?-we/1 or almo/ exactly p]p5dicul> to ! direction 9 #ahif4 ,secondly1 x w be notic$ 7,fig4 #fj7 t ! isoseismal l9es are n equidi/ant f "o ano!r4 ,on ! nor?-ea/ side1 !y are sep>at$ by di/ances ( #bj1 #cd1 #ee1 & #ea miles2 & on ! s\?-we/ side by di/ances ( #ac-a_/d1 #be1 #fj1 & #gg miles4 ,x foll[s f ?is t ! fault-surface mu/ hade or slope t[>ds ! nor?-ea/2 =1 ne> ! epic5tre1 ! int5sity is greate/ & dies out m sl[ly on ! side t[>ds :i* ! fault hades4 ,if we c\ld asc]ta9 any "o place ?r\gh :i* ! fault pass$1 its position w\ld ?us be completely det]m9$4 ,un=tunately1 !re is no decisive evid5ce on ?is po9t4 ,!re are1 h[ev]1 sev]al places to ! s\?-we/ ( ,h]e=d :]e ! int5sity ( ! %ock 0 di/9ctly less ?an 9 ! surr\nd+ di/rict1 & x is possible t ?is 0 due to _! neighb\rhood to ! fault-l9e 7see p4 #ace74 ,if s1 ! orig9at+ fault mu/ h ext5d$ f a po9t ab\t a mile & a half we/ ( ,h]e=d = a di/ance ( ab\t #af miles to ! s\?-ea/2 & a fault 9 ?is position w\ld c]ta9ly satisfy all ! details ( ! seismic evid5ce4 ,,nature ,,( ,,! ,,%ock4 ,?r\gh\t ! di/urb$ area1 consid]able v>iations 7 obs]v$ 9 ! nature ( ! %ock4 ,^! *anges 7 due to ! m]e size ( ! focus1 to its elongat$ =m &1 z w be se51 to its discont9uity1 & also to ! di/ance ( ! place ( obs]vation f ! epic5tre4 ,at places ne> ! epic5tre1 rapid *anges 9 ! direction ( ! %ock 7 obs]v$ ow+ to ! l>ge angle subt5d$ by ! focus2 :ile1 at consid]able di/ances1 ?is angle be+ small1 ! *anges ( direction 7 imp]ceptible4 ,a fur!r v>iation ) ! di/ance 0 an increase 9 ! p]iod ( ! vibrations4 ,close to ! epic5tre1 ! g5]al impression 0 t ( cross+ ! wake ( a /eam] 9 a v %ort r[+-boat1 or ( rid+ 9 a c>riage )\t spr+s4 ,at di/ances ( a hundr$ miles or m1 ! movem5t is describ$ z be+ ( a pleasant1 g5tle1 undulat+ "*1 l t felt dur+ ! rock+ ( a %ip at an*or or 9 a c>riage ) well-appo9t$ spr+s4 ,! mo/ rem>kable feature ( ! %ock1 h[ev]1 0 its division into two di/9ct p>ts or s]ies ( vibrations1 sep>at$ by an int]val1 la/+ two or ?ree seconds1 ( absolute re/ & quiet4 ,& ?is 0 no m]e local ph5om5on4 ,) ! exception ( a n>r[ b& t w be ref]r$ to pres5tly1 records ( ! d\ble %ock come f ne>ly all p>ts ( ! di/urb$ area1 ev5 f di/ricts s remote z ! ,isle ( ,man & ! ea/ ( ,irel&4 ,! two p>ts diff]$ 9 int5sity1 9 duration1 & 9 ! p]iod ( _! con/itu5t vibrations4 ,= in/ance1 at ,oakl&s 7ne> ,*>d71 a %iv]+ motion 0 fir/ felt1 & !n1 aft] ab\t ?ree or f\r seconds1 a di/9ct rock+ f side to side4 ,at ,exet]1 !re 0 a sudd5 tremor la/+ ab\t two seconds1 foll[$1 aft] two or ?ree seconds1 by ano!r & m sev]e %ak+ la/+ f\r or five seconds4 ,aga91 at ,we/ ,cross 7ne> ,swansea71 an undulatory movem5t = ab\t f\r seconds 0 foll[$ soon aft] by a tremul\s %ock4 ,at ,liv]pool1 ! durations ( ! fir/ "p1 int]val1 & second "p 7 respectively e/imat$ at ab\t six1 two1 & f\r seconds4 ,z a fir/ result ( ! obs]vations1 !n1 x appe>s t 9 ! s\?-ea/ half ( ! di/urb$ area1 ! second "p ( ! %ock 0 ! /rong]1 ( great] duration & consi/$ ( long]-p]iod vibrations 7z at a1 ,fig4 #fa72 :ile1 9 ! nor?-we/ half1 ! same features *>act]is$ ! fir/ "p ( ! %ock 7b1 ,fig4 #fa74 ,a clos] exam9ation ( ! records %[s1 h[ev]1 t ! b\nd>y betwe5 ! two portions ( ! di/urb$ area 0 n a /raight l9e1 b slightly curv$1 ! concavity fac+ ! s\?-ea/4 ,! brok5 l9e on ! map 7,fig4 #fj71 :i* is hyp]bolic 9 =m1 repres5ts r\ghly ! position ( ?is curv$ b\nd>y4#fd ,illu/ration3 ,,fig4 #fa4--,nature ( %ock ( ,h]e=d e>?quake4 ,along ?is hyp]bolic b\nd>y-l9e1 or r )9 a n>r[ b& ( :i* x is ! c5tral l9e1 ! %ock lo/ its d\ble "*1 & 0 manife/$ z a s+le s]ies ( vibrations gradually increas+ 9 int5sity & !n dy+ away4 ,close to ! edges ( ?is b&1 c>eful obs]v]s 7 able to di/+ui% two maxima ( int5sity connect$ by a cont9u\s s]ies ( tremors 7c1 ,fig4 #fa74 ,?us1 )9 ! b&1 ! two s]ies ( vibrations1 :i* else:]e 7 isolat$1 mu/ h be5 sup]pos$ on "o ano!r2 :ile1 ne> ! edges ( ! b&1 ! conclud+ tremors ( ! fir/ s]ies ov]lapp$ ! initial tremors ( ! second4 ,orig9 ( ! ,d\ble ,s]ies ( ,vibrations4--,! ,h]e=d e>?quake ?us belongs to ! same class z ! ,neapolitan1 ,&alusian1 ,*>le/on1 & ,rivi]a e>?quakes4 ,z 9 ^! cases1 ! hypo!sis ( a s+le focus is inadmissible4 ,! division ( ! di/urb$ area into two regions ( opposite relative int5sity1 duration1 etc41 is suffici5t pro( t a s+le s]ies ( vibrations 0 n duplicat$ by reflection or refraction1 or by sep>ation into longitud9al & transv]se waves4 ,x is equally conclusive aga9/ a repetition ( ! impulse )9 ! same focus4 ,we mu/ !re=e inf] t ! focus consi/$ ( two ne>ly or q deta*$ portions arrang$ along a nor?-we/ & s\?-ea/ l9e1 & t ! impulse at ! nor?-we/ focus 0 ! /rong] ( ! two4 ,! only "q t rema9s to be decid$ is :e!r ! impulses at ! two foci 7 simultane\s or n4 ,n[1 if ! impulses occurr$ at ! same in/ant1 ! waves f ! two foci w\ld travel ) ! same velocity1 & w\ld !re=e coalesce along a /raight b& :i* w\ld bisect at "r angles ! l9e jo9+ ! two epic5tres4 ,b we h already se5 t ?is b& is curv$1 & x ?us foll[s t ! two impulses 7 n simultane\s4 ,aga91 s9ce ! concavity ( ! hyp]bolic b& faces ! s\?-ea/1 ! waves f ! nor?-we/ focus mu/ h travell$ f>!r ?an ^? f ! s\?-ea/ focus be=e ! two met along ! hyp]bolic b&2 9 o!r words1 ! impulse at ! nor?-we/ focus mu/ h occurr$ two or ?ree seconds be=e ! impulse at ! o!r4 ,position & ,dim5sions ( ! ,two ,foci4--,!re c be little d\bt t ! impulse at ! nor?-we/ focus 0 responsible = ! great] damage to build+s at ,h]e=d1 ,d9$or1 ,f[nhope1 etc4 ,! c5tre ( its epic5tral area mu/ !re=e lie ab\t ?ree miles s\?-ea/ ( ,h]e=d4 ,x is probable1 also1 t ! correspond+ c5tre ( ! o!r focus is simil>ly plac$ ) respect to ! s\?-ea/ portion ( ! isoseismal #h--t is1 ab\t two or ?ree miles nor?-ea/ ( ,ross4 ,^! two po9ts are eight or n9e miles ap>t4 ,n[1 s9ce1 z we %all see1 ! mean surface-velocity ( ! e>?-waves 0 ab\t #cjjj feet p] second1 & ! mean duration ( ! quiet int]val betwe5 ! two s]ies 0 #c-a_/b seconds1 ! ne>e/ ends ( ! two foci mu/ h be5 sep>at$ by a di/ance ( n less ?an two miles4 ,moreov]1 s9ce ! s]ies ( vibrations f ! nor?-we/ or ,h]e=d focus la/$ a few seconds long] ?an t f ! s\?-ea/ or ,ross focus1 ! =m] mu/ h be5 ab\t two miles long] ?an ! latt]1 & we may !re=e e/imate _! l5g?s at ab\t eight & six miles respectively4 ,includ+ ! undi/urb$ int]m$iate portion1 ?is w\ld give a total l5g? ( focus ( ab\t #af miles1 a result we h already inf]r$ f ! dim5sions ( ! isoseismal #h4 ,,direction ,,( ,,! ,,%ock4 ,al?\gh no "q 0 ask$ ) reg>d to ! direction ( ! %ock1 no few] ?an #dfi obs]v]s made notes on ?is po9t4 ,z a g5]al rule1 _! det]m9ations are extremely r\gh1 few ref]r+ to m ?an ! eight pr9cipal po9ts ( ! compass4 ,moreov]1 9 any "o place1 ! directions assign$ to ! %ock are v v>i$4 ,= in/ance1 9 ! city & suburbs ( ,birm+ham1 eight obs]v]s give ! direction along a nor? & s\? l9e1 eight ea/ & we/1 elev5 nor?-we/ & s\?-ea/1 & five nor?-ea/ & s\?-we/1 :ile !re are five o!r int]m$iate e/imates4 ,b1 :5 ^! directions are plott$ on a map ( ! di/rict1 x is se5 at once t !y are ei!r ne>ly p>allel or p]p5dicul> to ! roads 9 :i* ! obs]v]s 7 liv+2 t is1 ! app>5t direction ( ! %ock 0 at "r angles to "o ( ! pr9cipal walls ( ! h\se4 ,?is1 ( c\rse1 is a result to be anticipat$1 =1 :atev] be ! direction ( ! e>?quake-motion1 a h\se t5ds to oscillate 9 a plane p]p5dicul> to "o or o!r ( its walls4 ,x is extraord9>y to h[ great a di/ance ! direction ( ! %ock is p]ceptible4 ,records come f ,brighton 7#acg miles f ! epic5tre71 ,maldon 9 ,essex 7#add miles71 ,h>rogate 7#adg miles71 ,d\glas 9 ! ,isle ( ,man 7#afg miles71 ,dubl9 7#agf miles71 & ,balt+lass 9 ,co4 ,wickl[ 7#ahj miles74 ,nev]!less1 :atev] ! di/ance may be1 ! s5se ( direction mu/ be mo/ p]ceptible 9 ^? h\ses ^: pr9cipal walls are at "r angles to ! true direction ( ! e>?quake-motion1 & we %\ld !re=e expect to f9d ! obs]vations ( direction mo/ frequ5tly made 9 su* h\ses1 or 9 o!rs :i* approximate to ?is situation4 ,?us1 ! av]age ( all ! obs]vations )9 a fairly small area %\ld give a result n v f> f ! true direction ( ! %ock2 &1 ! small] ! area & ! f>!r f ! epic5tre1 ! m reliable %\ld be ! result4 ,n[1 9 ,birm+ham ! mean direction ( ! %ock is ,e4 #ci ,n41 :i* diff]s only by #b f ! l9e jo9+ ! city to ! epic5tre2 9 ,london x is ,e4 #ba ,s41 ! diff]5ce be+ aga9 #b4 ,9 o!r cases1 ! obs]vations f diff]5t c\nties are gr\p$ toge!r1 & ! mean direction is tak5 to correspond to ! c5tre ( ! c\nty4 ,yet1 ev5 !n1 !re is (t5 a close agreem5t betwe5 ! mean direction ( ! %ock & ! direction ( ! c\nty-c5tre f ! epic5tre2 ! diff]5ce be+ n m ?an two or ?ree degrees 9 ! c\nties ( ,buck+ham1 ,devon1 ,/af=d1 ,w>wick1 & ,york4 ,9 o!r cases1 :]e ! deviation exce$s ?is am\nt1 ei!r ! numb] ( obs]vations is small or ! c\nty is ne> ! epic5tre & s subt5ds a l>ge angle4 ,two results ( "s importance foll[ f ?is analysis3 7#a7 t :ile1 ) a few isolat$ obs]vations1 ! me?od ( directions is almo/ sure to fail1 ) a l>ge numb] ( obs]vations closely gr\p$1 ! position ( ! epic5tre may be det]m9$ ) a fair approa* to accuracy2 & 7#b7 t1 at any rate outside a radius ( =ty miles1 ! e>?-waves travell$ 9 approximately /raight l9es outw>ds f ! epic5tre4 ,,coseismal ,,l9es ,,& ,,velocity ,,( ,,e>?-,,waves4 ,coseismal l9es 7 def9$ by ,mallet z long ago z #ahdi1 b1 ow+ to ! difficulty ( asc]ta9+ ! correct "t1 !y h s f> be5 ( little s]vice 9 ! inve/igation ( e>?quakes4 ,9 ! case ( ! ,h]e=d e>?quake1 ! di/ances trav]s$ by ! e>?-waves are small2 b1 on ! o!r h&1 ! "t-records are num]\s & frequ5tly tru/wor?y to ! ne>e/ m9ute4 ,reject+ all e/imates e>li] ?an #e4cb ,a4,m41 & lat] ?an #e4cf1 z well z a numb] at #e4ce1 !re rema9 fairly good obs]vations f #cha places1 & exceptionally accurate ones f #cc places4 ,! latt] 7 obta9$ f signalm5 & o!r c>eful obs]v]s :o 7 9 possession ( ,gre5wi* "t1 or :o comp>$ _! wat*es %ortly aft]w>ds ) well-regulat$ wat*es4 ,) evid5ce s abundant1 a new me?od ( draw+ coseismal l9es becomes possible4 ,accord+ to ?is me?od1 ea* place ( obs]vation is indicat$ on ! map by a m>k correspond+ to ! p>ticul> m9ute record$4 ,if ! records 7 q correct1 !re w\ld be a c5tral area occupi$ by ! m>ks correspond+ to #e4cb ,a4,m41 surr\nd$ by a s]ies ( zones 9 :i* ! times 7 respectively #e4cc1 #e4cd1 & #e4ce4 ,! curves sep>at+ ^! zones w\ld be coseismal l9es correspond+ to ! times #e4cb-a_/b1 #e4cc-a_/b1 & #e4cd-a_/b4 ,ow+1 h[ev]1 to ! inevitable inaccuracy ( all ! "t-records1 ^! diff]5t zones intrude on "o ano!r1 & ! coseismal l9es h !re=e to be drawn ab\t half-way ?r\gh ! ov]lapp+ regions1 special weight be+ attribut$ to ! app>5tly m accurate obs]vations4 ,illu/ration3 ,,fig4 #fb4--;,coseismal l9es ( ! ,h]e=d e>?quake4 7,davison47 ,! coseismal l9es obta9$ 9 ?is mann] are repres5t$ by ! cont9u\s curves 9 ,fig4 #fb4 ,! isoseismals1 :i* are add$ = ! sake ( comp>ison1 are indicat$ by ! dott$ l9es4 ,x w be se5 t ! coseismal l9es are elongat$ 9 ! same direction z ! isoseismals1 b to a less ext5t1 & ?is no d\bt is due to ! fact t ! epo* select$ by ! majority ( obs]v]s 0 "o n f> f1 & slightly prec$+1 t ( ! maximum int5sity ( ! %ock4 ,n[1 ! av]age di/ance betwe5 ! two inn] coseismals is #cb-c_/d miles1 betwe5 ! two out] ones 7s f> z drawn7 #ce-a_/f miles1 & betwe5 ! fir/ & ?ird #fg-a_/f miles4 ,! mean surface-velocity betwe5 ! two inn] coseismals is !re=e #b1hhb feet p] second1 & betwe5 ! two out] ones #c1jie feet p] second4 ,!re is ?us an app>5t increase 9 ! velocity ) ! di/ance1 b ! accuracy ( ! coseismal l9es is unequal to e/abli%+ ?is z a fact4 ,! mean surface-velocity ( #b1iee feet p] second betwe5 ! fir/ & ?ird coseismals is probably1 h[ev]1 ! mo/ accurate e/imate ( ! surface-velocity yet made 9 a slight e>?quake4 ,,s\nd-,,ph5om5a4 ,nature ( ! ,s\nd4--,! s\nd :i* accompani$ ! %ock 0 ( ! same "* z t he>d dur+ all great e>?quakes4 ,x is (t5 describ$ 9 su* t]ms z a deep boom+ noise1 a dull heavy rumble1 a grat+ ro>+ noise1 or a deep groan or moan2 m r>ely z a ru/l+ or a l\d hiss+ ru%+ s\nd4 ,z a rule1 x began fa9tly1 increas$ gradually 9 /r5g?1 & !n z gradually di$ away2 & ?is no d\bt is ! reason :y x sometimes appe>$ z if an und]gr\nd tra9 or waggon 7 approa*+ quickly1 ru%+ b5ea? ! obs]v]1 & !n rec$+ 9 ! opposite direction4 ,occasionally1 ! s\nd 0 v l\d1 be+ comp>$ to ! noise ( _m traction-eng9es heavily lad5 pass+ close at h&1 or to a heavy cra% or peal ( ?und]4 ,b its *ief *>act]i/ic 0 its extraord9>y dep?1 z if x 7 almo/ too l[ to be he>d4 ,accord+ to "o obs]v]1 x 0 a l[ rumbl+ s\nd1 mu* l[] ?an ! l[e/ ?und]2 & ano!r comp>$ x to ! p$al notes ( a great organ1 only ( a deep] pit* ?an c be tak5 9 by ! human e>1 a noise m felt ?an he>d4 ,x w be se5 pres5tly h[ ! s\nd1 f its v dep?1 0 inaudible to _m p]sons4 ,a few obs]v]s describ$ ! s\nd 9 t]ms l ^? quot$ above1 b by f> ! l>g] numb] comp>$ x to "s m or less well-kn[n type1 & 9 _m cases ! resemblance 0 s close t ! obs]v] at fir/ attribut$ x to ! object ( comp>ison4 ,! descriptions1 :i* pres5t great v>ieties 9 detail1 may be classifi$ z foll[s3 7#a7 ,"o or sev]al traction-eng9es pass+1 ei!r alone or heavily lad51 sometimes driv5 furi\sly pa/2 a /eam-roll] pass+ ov] froz5 gr\nd or at a quick] pace ?an usual2 heavy waggons driv5 ov] /one pav+1 on a h>d or fro/y road1 9 a cov]$ way or n>r[ /reet1 or ov] holl[ gr\nd or a bridge2 express or heavy goods tra9s ru%+ ?r\gh a tunnel or deep cutt+1 cross+ a wood5 bridge or iron viaduct1 or a heavy tra9 runn+ on sn[2 ! grat+ ( a vessel ov] rocks1 or ! roll+ ( a lawn by an extremely heavy roll]2 7#b7 a l\d clap or heavy peal ( ?und]1 sometimes dull1 muffl$ or subdu$1 b mo/ (t5 di/ant ?und]2 7#c7 a moan+1 ro>+1 or r\gh1 /rong w9d2 ! ris+ ( ! w9d1 a heavy w9d press+ aga9/ ! h\se2 ! h[l+ ( w9d 9 a *imney1 a *imney or oil-factory on fire2 7#d7 ! tipp+ ( a load ( coal1 /ones1 or bricks1 a wall or ro( fall+1 or ! cra% ( a *imney ?r\gh ! ro(2 7#e7 ! fall ( a heavy weight or tree1 ! bang+ ( a door1 only m muffl$1 & ! bl[ ( a wave on ! sea-%ore2 7#f7 ! explosion ( a boil] or c>tridge ( dynamite1 a di/ant colli]y explosion1 di/ant heavy rock-bla/+ & ! boom ( a di/ant cannon2 7#g7 s\nds ( a miscellane\s "*1 su* z ! trampl+ ( _m m5 or animals1 an imm5se covey ( p>tridges on ! w+1 ! ro> ( a wat]fall1 ! passage ( a p>ty ( skat]s1 & ! r5d+ & settl+ toge!r ( huge masses ( rock4 ,! total numb] ( comp>isons made 0 #a1bfd4 ,( ^!1 #de4d p] c5t4 ref] to pass+ waggons1 etc41 #ae4j p] c5t4 to ?und]1 #ae4e to w9d1 #c4i to loads ( /ones fall+1 #b4g to ! fall ( a heavy body1 #g4b to explosions1 & #aj4c p] c5t4 to miscellane\s s\nds4 ,g5]ally1 ! s\nd adh]$ ?r\gh\t to "o ( ! types m5tion$ above1 &1 if x v>i$ at all1 v>i$ only 9 int5sity4 ,at "s places1 h[ev]1 ! "* ( ! s\nd 0 obs]v$ to *ange4 ,= in/ance1 "o p]son describ$ x z l ! rumbl+ ( a tra9 go+ ov] a bridge1 ) a t]rific cra%1 su* z is he>d 9 a ?und]/orm at ! in/ant :5 ! %ock 0 /ronge/1 ! rumbl+ dy+ away aft]w>ds = "s seconds4 ,inaudibility ( ! ,s\nd to "s ,obs]v]s4--,! total numb] ( obs]v]s :o give a detail$ acc\nt ( ! e>?quake is #b1fha1 &1 ( ^!1 #ei p] c5t4 /ate t !y he>d ! s\nd1 #bc p] c5t4 give no in=mation1 :ile #ah p] c5t4 di/9ctly say t !y he>d no s\nd2 t is1 r\ghly1 out ( e five obs]v]s1 ?ree he>d ! s\nd1 "o made no ref]5ce to x1 & "o fail$ to he> ! s\nd4 ,9 a few cases1 no d\bt1 ?is failure 0 due to ! di/ance ( ! obs]v]1 b ?is is f> f be+ a complete explanation2 =1 9 ,h]e=d%ire1 six out ( #agi1 & 9 ,gl\ce/]%ire #ag out ( #bbg1 obs]v]s he>d no s\nd4 ,nor is ! peculi>ity a local "o1 = at ,clifton two out ( five obs]v]s :o 7 awake did n he> ! s\nd1 at ,birm+ham f\r out ( #bc1 & 9 ,london1 eight out ( #ah4 ,ev5 9 ! same h\se1 x w\ld happ5 t "o obs]v] w\ld he> a s\nd z ( a heavily-lad5 traction-eng9e pass+1 :ile to ano!r x 0 q inaudible4 ,aga91 a l>ge numb] ( obs]v]s :o he>d ! s\nd expressly /ate t !y 7 unconsci\s ( any :ile ! %ock la/$4 ,! noise at fir/ resembl$ ! approa* ( a /eam-roll] or traction-eng9e up ! /reet1 x became gradually l\d]1 & !n ceas$ m or less sudd5ly z ! %ock began2 :ile1 to o!rs 9 ! same places1 ! s\nd cont9u$ to gr[ 9 l\dness until ! /ronge/ vibrations 7 felt4 ,ev5 :5 obs]v]s 9 ! same place agre$ 9 he>+ ! s\nd1 x pres5t$ itself to !m "u diff]5t aspects4 ,?us1 at ,h]e=d1 a cra% or bomb-l explosion 0 notic$ by "s1 b n by all1 obs]v]s2 at ,l$bury1 ! s\nd accord+ to "o began l a ru%+ w9d & culm9at$ 9 a l\d explosive report1 ano!r he>d a noise l di/ant ?und]1 :i* end$ :5 ! %ock began1 :ile a ?ird he>d no s\nd at all4 ,at places m di/ant f ! epic5tre1 ! same div]sity1 bo? 9 "* & int5sity1 is manife/$4 ,?us1 at ,birm+ham1 ! acc\nts ref] on ! "o h& to ! di/ant approa* ( a tra9 & ! ris+ ( ! w9d1 on ! o!r to ! reports ( l>ge cannons & to a noise z if tons ( dbris _h be5 hurl$ aga9/ ! wall ( ! h\se2 at ,bangor1 to muffl$ ?und]1 w9d ?r\gh trees1 & a l\d rumbl+ s\nd4 ,! fir/ explanation ( ^! app>5t anomalies :i* pres5ts itself is inatt5tion on ! "p ( ! obs]v]s2 b x is "o t w n be> exam9ation1 ?\gh x may apply 9 "s cases4 ,! s\nd is too l\d1 at any rate ne> ! epic5tre1 to escape notice1 & x is g5]ally he>d be=e ! %ock beg9s to be felt4 ,moreov]1 z describ$ 9 ! la/ *apt]1 ?ree out ( e f\r e>?quakes 9 ,japan are unaccompani$ by record$ s\nd1 & ! ,japanese z a race _c be accus$ ( su* con/ant inatt5tion4 ,! defect1 x c h>dly be d\bt$1 is inh]5t to ! obs]v]1 & n dep5d5t on ! conditions 9 :i* he is plac$4 ,t ! high] limit ( audibility v>ies ) diff]5t p]sons has long be5 kn[n2 & !re c be no reason = d\bt+ t !re is a simil> v>iability 9 ! l[] limit4 ,?us1 to "s obs]v]s1 ! s\nd rema9s inaudible ?r\gh\t1 h[ev] int5tly !y may be li/5+4 ,aga91 x is f\nd t1 ! deep] ! s\nd1 ! great] mu/ be ! /r5g? ( ! vibrations requir$ to r5d] !m audible4 ,z ! vibrations :i* rea* an obs]v] increase 9 p]iod1 x may !re=e happ5 t1 soon] or lat]1 ! /r5g? ( "s does n atta9 or exce$ t limit+ value1 &1 at t mom5t1 ! s\nd w cease to be he>d4 ,moreov]1 = vibrations ( a giv5 p]iod1 ?is limit+ value v>ies = diff]5t p]sons4 ,?us1 to "o obs]v]1 ! s\nd may become inaudible1 :ile ano!r may cont9ue to he> x4 ,la/ly1 ! vibrations :i* affect an obs]v] at any mom5t are ( v>i\s /r5g? & p]iod4 ,"o may he> all p]haps1 :ile a second may be able to he> "s & n o!rs4 ,?us1 to "o obs]v]1 ! s\nd may be l a ris+ w9d1 to ano!r l a heavy traction-eng9e pass+2 "o may he> ! cra%es :i* accompani$ ! /ronge/ "p ( ! %ock1 :ile a second may be deaf to ! same vibrations2 to "o ! s\nd may become cont9ually l\d] & cease abruptly1 to ano!r x may increase to a maximum & !n die away4 ,s\nd-,area4--,:ile ! s\nd 0 a v prom95t feature ( ! e>?quake 9 & ne> ! epic5tral area1 records at a great di/ance are naturally difficult to obta91 &1 on ?is acc\nt1 ! numb] ( /ations = det]m9+ ! b\nd>y ( ! s\nd-area is too small to all[ ( x be+ accurately drawn4 ,z a rule1 h[ev]1 x mu/ lie betwe5 ! isoseismals #e & #d1 b x is less ne>ly circul> ?an ei!r ( ^! l9es4 ,its l5g?1 f nor?-we/ to s\?-ea/1 is #cbj miles1 its bread? #bhd miles1 & ! area conta9$ by x ab\t #gj1jjj squ>e miles1 or r\ghly two-?irds t ( ! di/urb$ area4 ,isac\/ic ,l9es4--,! dott$ l9es 9 ,fig4 #fj repres5t isac\/ic l9es--t is1 l9es :i* pass ?r\gh all places :]e ! p]c5tage ( obs]v]s :o record$ _! p]ception ( ! s\nd is ! same4 ,= in/ance1 if we take any po9t 9 ! l9e m>k$ #hj & describe a small circle ) t po9t z c5tre1 !n #hj p] c5t4 ( ! obs]v]s )9 t circle w\ld he> ! e>?quake-s\nd4 ,! isac\/ic l9es ?us %[ h[ ! audibility ( ! s\nd v>ies ?r\gh\t ! s\nd area4 ,to draw ! curves ) a close approa* to accuracy1 ! unit ( area %\ld be small & ( con/ant dim5sions2 b1 9 ! pres5t case1 ow+ to ! comp>ative paucity ( ! obs]vations1 a small] unit ?an ! c\nty w\ld give unreliable results4#fe ,at ! c5tre ( ea* c\nty1 ! s\nd audibility may be reg>d$ z proportional to ! p]c5tage ( ! total numb] ( obs]v]s )9 ! c\nty :o di/9ctly he>d ! s\nd4 ,to draw ! curve m>k$ #ej1 ! c5tre ( e c\nty 9 :i* ! av]age p]c5tage is less ?an #ej is jo9$ to ! c5tres ( ^? adjo9+ c\nties 9 :i* x is above #ej1 & ^! l9es are !n divid$ 9 ! prop] ratio s z to give a po9t :]e ! p]c5tage w\ld be exactly #ej4 ,a numb] ( po9ts at :i* ! p]c5tage is #ej is ?us obta9$1 & ! curve drawn ?r\gh !m is ! requir$ isac\/ic l9e4 ,! p]c5tage ( audibility v>ies f #hg 9 ,h]e=d%ire to #bc 9 ,essex & ! ea/ ( ,irel&1 b ! only isac\/ic l9es :i* c be completely drawn are ^? t correspond to ! p]c5tages betwe5 #hj & #ej inclusive4 ,! peculi> =m ( ! isac\/ic l9es w be evid5t at a glance4 ,!y be> little relation to ! isoseismal l9es4 ,_! greate/ ext5sions are n along ! axes ( ^? l9es1 b 9 two directions :i* are a little ea/ ( nor?-ea/ & s\? ( s\?-we/4 ,!y lie inde$ along a hyb]bolic l9e :i*1 t[>ds ! s\?-we/1 agrees closely ) ! curvil9e> axis ( ! hyp]bolic b& repres5t$ by ! brok5 l9e 9 ,fig4 #fj4 ,t[>ds ! nor?-ea/1 ! co9cid5ce is n s close1 b ?is is *iefly ow+ to ! magnitude ( ! nor!rn c\nties1 :i* causes a deflection ( ! isac\/ic l9es t[>ds ! nor?4 ,x w be rememb]$ t ! hyp]bolic b& is ! area )9 :i* ! vibrations f ! two foci 7 sup]pos$4 ,n[1 ! s\nd accompani$ ea* "p ( ! %ock1 & ceas$ entirely dur+ ! int]val betwe5 !m4 ,also1 ! /rong] s]ies ( vibrations 0 accompani$ by ! l\d] s\nd2 b1 :ile ! diff]5ce 9 /r5g? 0 consid]able betwe5 ! two p>ts ( ! %ock1 x 0 v slight betwe5 ! two s\nds4 ,!re is !re=e no m>k$ di/ortion ( ! isoseismal l9es :5 cross+ ! hyp]bolic b&1 :ile ! isac\/ic l9es are completely div]t$ f _! normal c\rse4 ,?us1 ! /udy ( ! isac\/ic l9es /rongly confirms ! conclusions at :i* we h arriv$ above 7p4 #bbc7--namely1 t !re 7 two di/9ct foci arrang$ 9 a nor?-we/ & s\?-ea/ l9e1 & t ! impulse at ! =m] focus occurr$ a few seconds e>li] ?an t at ! latt]4#ff ,v>iations 9 ! ,nature ( ! ,s\nd ?r\gh\t ! ,s\nd-area4--,9 "o respect1 ! s\nd exhibit$ a m>k$ uni=mity all ov] ! s\nd-area--namely1 9 its great dep?2 ! ^w heavy be+ us$ 9 "o out ( e f\r acc\nts ( ! s\nd1 :e!r close to ! epic5tre or ne> ! b\nd>y ( ! s\nd-area4 ,! type ( comp>ison employ$ v>ies 9 diff]5t p>ts ( ! s\nd-area4 ,z we rec$e f ! orig91 ! s\nd becomes on ! av]age less l ?und] or explosions & m l w9d4 ,! ref]5ces to pass+ waggons1 etc41 are s num]\s t x is possible to draw curves1 9 ! same way z isac\/ic l9es1 :i* repres5t equal p]c5tages ( comp>ison to ?is type out ( ! total numb] ( comp>isons4 ,! curves are some:at incomplete1 b x is notewor?y t ^? correspond+ to ! high] p]c5tages cl+ to ! extremities ( ! hyp]bolic b&1 probably because ! un9t]rupt$ duration ( ! s\nd is great] !re ?an else:]e4 ,! effect ( di/ance f ! epic5tre1 h[ev]1 is mo/ noticeable 9 connection ) *anges 9 ! "* ( ! s\nd4 ,x is only on ! imm$iate neighb\rhood ( ! orig9 t ! explosive reports or cra%es 7 he>d 9 ! mid/ ( ! rumbl+ s\nd4 ,at a mod]ate di/ance1 ! s\nd be=e & aft] ! %ock became smoo!r1 :ile ! s\nd :i* accompani$ ! %ock reta9$ to a c]ta9 ext5t its r\gh] & m rumbl+ or grat+ "*4 ,close to ! b\nd>y ( ! s\nd-area1 ! irregul>ities 7 /ill fur!r smoo!d away1 & ! only s\nd he>d 0 l ! l[ roll ( di/ant ?und]4 ,! explanation ( ^! *anges dep5ds on ! fact t1 z we rec$e f ! epic5tre1 ! vibrations ( e p]iod t5d to become inaudible4 ,! limit+ vibrations ( ! :ole s]ies w be ! fir/ to be lo/1 especially ^? ( ! longe/ p]iod4 ,?us1 ne> ! epic5tre1 s\nd-vibrations ( _m diff]5t p]iods w be he>d1 & ! s\nd w be m complex ?an x is else:]e4 ,! great] ! di/ance1 ! n>r[] are ! limits ) reg>d to p]iod betwe5 :i* ! audible vibrations lie1 until1 ne> ! b\nd>y ( ! s\nd-area1 ! s\nd becomes an almo/ monoton\s deep gr[l ( ne>ly uni=m int5sity4 ,"t-relations ( ! ,s\nd & ,%ock4--,! pr9cipal epo*s to be comp>$ are ! beg9n+1 ! epo* ( maximum int5sity1 & ! end4 ,! beg9n+ ( ! s\nd prec$$ t ( ! %ock 9 #hb p] c5t4 ( ! obs]vations on ?is epo*1 co9cid$ ) x 9 #ab1 & foll[$ x 9 #f p] c5t42 ! epo* ( maximum int5sity prec$$ t ( ! %ock 9 #ba p] c5t4 ( ! records1 co9cid$ ) x 9 #gc1 & foll[$ x 9 #f p] c5t42 :ile ! end ( ! s\nd prec$$ t ( ! %ock 9 #bb-a_/b p] c5t41 co9cid$ ) x 9 #bg-a_/b1 & foll[$ x 9 #ej p] c5t4 ,?us1 z a g5]al rule1 ! beg9n+ ( ! s\nd prec$$ t ( ! %ock1 ! s\nd 0 l\de/ :5 ! %ock 0 /ronge/1 & ! end ( ! s\nd foll[$ t ( ! %ock4 ,9 o!r words1 ! duration ( ! s\nd 0 9 mo/ cases great] ?an t ( ! %ock4 ,,m9or ,,e>?quakes4 ,( ! twelve und\bt$ m9or e>?quakes1 n9e occurr$ be=e1 & ?ree aft]1 ! pr9cipal %ock1 ! times ( ! fir/ elev5 ly+ betwe5 limits ab\t sev5 h\rs ap>t4 ,) ?ree exceptions1 ! records are insuffici5t to det]m9e ! positions ( ! epic5tre ) any approa* to exactness4 ,! fir/ occurr$ at ab\t #aa or #aa4cj ,p4,m4 on ,decemb] #af?4 ,! b\nd>y ( ! di/urb$ area1 :i* co9cides ne>ly ) t ( ! fif? %ock 7,e1 ,fig4 #fc71 is #ig miles long f nor?-we/ to s\?-ea/1 #hc miles wide1 & conta9s ab\t #f1cjj squ>e miles4 ,! focus 0 app>5tly situat$ betwe5 ! two foci ( ! pr9cipal e>?quake & p>tly co9cid$ ) !m4 ,illu/ration3 ,,fig4 #fc4--,map ( m9or %ocks ( ,h]e=d e>?quake4 7,davison47 ,!n came ?ree slight %ocks 7at ab\t #a ,a4,m4 on ,decemb] #ag?1 #a4cj or #a4de ,a4,m41 & #b ,a4,m471 ab\t :i* little is kn[n except t !y probably orig9at$ some:]e ne> ! ,ross focus4 ,! fif? %ock 7,e1 ,fig4 #fc7 occurr$ at ab\t #c ,a4,m41 & di/urb$ an area #ajd miles 9 l5g?1 #gi miles 9 wid?1 & ab\t #f1djj squ>e miles 9 area4 ,its b\nd>y occupies approximately ! position t w\ld be tak5 by an isoseismal ( int5sity betwe5 #g & #f ( ! pr9cipal e>?quake4 ,we may !re=e inf] t ?is %ock & ! pr9cipal e>?quake 7 caus$ by slips along ! same fault & 9 ab\t ! same region ( ! fault4 ,also1 z !re is no evid5ce ( discont9uity 9 ! vibrations ( ! m9or %ock1 x is probable t ! focus 0 cont9u\s1 & occupi$ ! space betwe5 ! two foci ( ! pr9cipal e>?quake1 z well z "p or ! :ole ( bo? ^! foci4 ,! next f\r %ocks occurr$ at ab\t #c4cj1 #d1 #e1 & #e4bj ,a4,m41 & 7 m closely associat$ ) ! ,ross ?an ) ! ,h]e=d focus1 & !n foll[$ ! pr9cipal e>?quake at #e4cb ,a4,m4 ,a few m9utes lat]1 at #e4dj or #e4de ,a4,m41 a v slight %ock 0 felt1 ! focus ( :i* 0 possibly situat$ 9 ! c5tral region betwe5 ! two foci4 ,! next1 at ab\t #f4ae ,a4,m4 7,k1 ,fig4 #fc71 di/urb$ an area #da miles long1 #bg miles broad1 & conta9+ ab\t #hgj squ>e miles4 ,its focus mu/ h co9cid$ approximately ) ! ,ross focus ( ! pr9cipal e>?quake1 & ?is 0 also ! case probably ) ! la/ %ock ( all1 :i* occurr$ on ,july #ai?1 #ahig1 at #c4di ,a4,m4 ,,orig9 ,,( ,,! ,,e>?quakes4 ,! great] "p ( ! epic5tral di/rict is cov]$ by a %eet ( ,old ,r$ ,s&/one 7,fig4 #fd71 b1 j to ! nor?-ea/ ( ! position laid d[n = ! orig9at+ fault 7indicat$ by ! /raight brok5 l9e71 is ! well-kn[n ,woolhope anticl9al1 by :i* ,silurian b$s are br\ght to ! surface4 ,! anticl9al axis runs approximately nor?-we/ & s\?-ea/1 & is ?us r\ghly p>allel to ! e>?quake-fault4 ,moreov]1 ! ?9n+-out & occasional disappe>ance ( "s ( ! ,silurian b$s on ! s\?-we/ side ( ! anticl9al 7z comp>$ ) ^? on ! nor?-ea/ side7 is sugge/ive ( a nor?-we/ & s\?-ea/ fault or rapid flexure at or ne> ! s\?-we/ junction ( ! ,old ,r$ ,s&/one & ! ,silurian /rata4 ,if x be a fault1 x mu/ hade to ! nor?-ea/1 & w\ld !re=e satisfy two ( ! conditions det]m9$ by ! seismic evid5ce4 ,x w\ld lie1 h[ev]1 ab\t two miles too f> to ! nor?-ea/1 be+ 9 fact to ! nor?-ea/ ( ! villages :i* suff]$ mo/ f ! e>?quake4 ,illu/ration3 ,,fig4 #fd4--;,geology ( meizoseismal area ( ,h]e=d e>?quake4 7,davison47 ,b only a few miles to ! s\?-ea/ ( ! ,woolhope anticl9al1 & almo/ 9 ! same l9e ) x1 !re is a second anticl9al1 t ( ,may ,hill4 ,?is is a triangul> area1 & is kn[n to be b\nd$ on all ?ree sides by faults4 ,! fault on ! nor?-ea/ side has an av]age nor?-we/ & s\?-ea/ direction1 &1 if x 7 cont9u$ ?r\gh ! ,old ,r$ ,s&/one t[>ds ! nor?-we/1 b b5d+ at fir/ a few degrees m to ! we/1 x w\ld pass ?r\gh a po9t ab\t #a-a_/b miles we/ ( ,h]e=d4 ,x is wor?y ( notice t bo? ?is fault & ano!r ne>ly p>allel to x1 ab\t half-a-mile f>!r nor?-ea/1 /op1 accord+ to ! ,geological ,survey map1 at ! po9ts :]e !y ent] ! ,old ,r$ ,s&/one4 ,! latt] is an area :i* has nev] be5 inve/igat$ ) ?or\ghness by mod]n /ratigraphical me?ods1 & 9 :i* x is difficult to trace faults4 ,x !re=e appe>s n improbable t ! e>?quakes 7 due to slips along a cont9uation ( ?is fault4 ,:e!r ?is be ! case or n1 h[ev]1 x is cle> t ! e>?quake-fault mu/ pass betwe5 ! anticl9al areas ( ,woolhope & ,may ,hill1 ! =m] be+ on ! nor?-ea/1 & ! latt] on ! s\?-we/1 side ( ! fault4 ,at ! ,h]e=d focus1 ! fault mu/ hade to ! nor?-ea/2 &1 at ! ,ross focus1 x is probable1 f ! di/ribution ( places :]e damage occurr$ to build+s1 t x hades to ! s\?-we/ ,if ?is be ! case1 ! fault mu/ *ange 9 hade betwe5 ! two foci4 ,h[ long a "t _h elaps$ s9ce ! la/ sign ( gr[? 9 ! e>?quake-fault took place1 x is impossible to say2 b x mu/ be _m ye>s 9 l5g?4 ,dur+ ?is int]val1 ! /resses t5d+ to produce movem5t along ! fault-s]vice _h be5 gradually increas+1 until !y 7 suffici5t to ov]come ! resi/ance oppos$ to !m4 ,x is wor?y ( notice t ! e>lie/ p]ceptible movem5ts 7 slight4 ,_! function seems to h be5 to prep>e ! way = ! great slips by equalis+ ! diff]5ce betwe5 /ress & resi/ance ov] a l>ge area ( ! fault-surface4 ,we _c trace ) accuracy ! transf]5ce ( ! seat ( movem5t f "o "p ( ! fault-surface to ano!r4 ,! fir/ slip seems to h tak5 place *iefly 9 ! region betwe5 ! two foci ( ! pr9cipal e>?quake2 possibly x ov]lapp$ bo? ( !m p>tly4 ,! next ?ree slips 7 app>5tly 9 ! neighb\rhood ( ! ,ross focus1 & 7 foll[$ by a fif? 9 ! same area z ! fir/4 ,!n came a s]ies ( small movem5ts t we _c locate fur!r ?an by say+ t !y 7 m closely connect$ ) ! ,ross focus ?an ! o!r4 ,9 consequ5ce ( ! prelim9>y slips )9 & ne> ! ,ross focus1 ! effective /ress 9 t portion ( ! fault 0 dim9i%$2 & ?is may be ! reason :y ! fir/ great slip took place at ! ,h]e=d focus4 ,! imm$iate result ( su* a movem5t w\ld naturally be an increase ( /ress 9 & beyond ! t]m9al regions1 & ! next slip might h be5 expect$ 9 an area p>tly ov]lapp+ ! ,h]e=d focus1 & ei!r to ! nor?-we/ or s\?-ea/ ( x4 ,in/ead ( ?is1 = a di/ance ( two miles 9 ! latt] direction1 !re 0 n ! lea/ p]ceptible movem5t dur+ ! pr9cipal e>?quake1 & ! second great slip occurr$ 9 ! region beyond occupi$ by ! ,ross focus4 ,?is second slip1 moreov]1 occurr$ )9 two or ?ree seconds aft] ! o!r2 t is1 be=e ! e>?-waves _h "t to travel f ! ,h]e=d to ! ,ross focus4 ,9 o!r words1 ! slip at ! ,ross focus 0 n a consequ5ce ( ! slip at ! ,h]e=d focus2 b bo? 7 due to a s+le g5]ative ef=t4 ,n[1 a section drawn p>allel to ! e>?quake-fault & on ! nor?-ea/ side ( x1 w\ld %[ an anticl9e ne> ! ,h]e=d focus & a correspond+ syncl9e ne> ! ,ross focus1 ) an undisplac$ portion 9 ! int]m$iate region2 :ile a p>allel section on ! o!r side ( ! fault w\ld %[ a syncl9e ne> ! ,h]e=d focus1 an anticl9e ne> ! ,ross focus1 & aga9 an undisplac$ portion 9 ! int]m$iate region4 ,if fur!r movem5ts t5d+ to acc5tuate su* a /ructure 7 to occur 7t is1 if ! anticl9als 7 to be made m anticl9al & ! syncl9es m syncl9al71 !re w\ld !re=e be two slips1 "o 9 ea* focus2 :ile1 along ! fault-surface betwe51 !re w\ld be practically no displacem5t4 ,at any rate1 ! e>li] /resses 9 t region may h be5 fully reliev$ by two slight prelim9>y slips 7^? caus+ ! fir/ & fif? m9or e>?quakes71 & ^? result+ f ! great displacem5ts by ! fir/ aft]-slip :i* foll[$ 9 ab\t t5 m9utes4 ,half-an-h\r lat]1 ano!r slip took place at ! ,ross focus1 & by ?is ! equilibrium ( ! rock-masses 0 almo/ completely re/or$2 = we h no c]ta9 evid5ce ( any fur!r movem5ts until sev5 mon?s h elaps$ 7,july #ai?1 #ahig71 :5 !re 0 a f9al slip 9 ! same region ( ! fault4 ,,! ,,inv]ness ,,e>?quake ,,( ,,septemb] #ah,,?1 #aija4 ,betwe5 ! nor?-ea/ end ( ,lo* ,ness & ! ,moray ,fir? at ,inv]ness1 !re lies a tract ( l& n m ?an sev5 miles 9 l5g?1 :i* is notable z "o ( ^? mo/ frequ5tly %ak5 by e>?quakes 9 ! ,briti% ,isl&s4 ,9 ! int5sity ( its %ocks x is inf]ior to ! s\?-ea/ ( ,essex & ! c5tre ( ,h]e=d%ire1 &1 9 m]e numb]1 to ! celebrat$ village ( ,comrie 9 ,p]?%ire4 ,b1 9 ! int]e/ ( its seismic ph5om5a1 9 ! light :i* !y ca/ on ! developm5t ( ! e>?'s cru/1 ! neighb\rhood ( ,inv]ness has no equal 9 ,great ,brita91 & n _m sup]iors 9 any "p ( ! _w4 ,= ?is importance f a seismological po9t ( view1 ! di/rict is indebt$ to ! great fault :i* trav]ses ,scotl& along ! l9e ( ! ,cal$onian ,canal1 & to ! fact t ?is fault1 al?\gh x dates f ,old ,r$ ,s&/one times1 has n yet f9i%$ gr[+4 ,z results ( its =mation1 we h ! almo/ /raight cliff along ! s\?-ea/ coa/ ( ,ross%ire1 & ! long *a9 ( lakes1 beg9n+ ) ,lo* ,do*f\r & ,lo* ,ness1 & end+ ) ,lo* ,oi*1 ,lo* ,lo*y1 & ,lo* ,l9nhe4 ,z evid5ces ( its p]si/5t ?\gh int]mitt5t gr[?1 we h ! slight tremors & e>?-s\nds occasionally obs]v$ at & ne> ,=t ,william1 & ! mu* /rong] %ocks felt 9 ! neighb\rhood ( ,inv]ness4 ,dur+ ! n9ete5? c5tury !re 7 ?ree /rong e>?quake %ocks 9 ?is di/rict4 ,! fir/ & mo/ sev]e occurr$ on ,augu/ #ac?1 #ahaf1 & 0 felt ov] ! great] "p ( ,scotl&2 ! second on ,febru>y #bnd1 #ahhh2 & ! ?ird & weake/ on ,novemb] #ae?1 #ahij4 ,?is la/ %ock 0 foll[$ by sev]al slight] ones1 ! s]ies end+ ) a r sm>t %ock on ,decemb] #ad?4 ,betwe5 ?is date & ! summ] ( #aija no e>?quakes seem to h be5 felt at or any:]e ne> ,inv]ness4 ,,prep>atory ,,%ocks4 ,! date ( ! fir/ %ock ( #aija is n q c]ta94 ,"o is said to h be5 felt at ,ald\rie 7see ,fig4 #ff7 "s "t 9 ,june1 & a second at ,do*g>ro* 9 ,july4 ,^! may h be5 succe$$ by o!rs too slight to attract mu* notice1 b ! fir/ to be g5]ally obs]v$ occurr$ on ,septemb] #af? at #f4d ,p4,m4 ,a weak tremor1 accompani$ by a fa9t s\nd1 0 p]ceiv$ ov] a ne>ly circul> area ab\t #ab miles 9 diamet]1 & ) its c5tre ab\t #a-a_/b miles s\? ( ,do*g>ro*4 ,on ! next day1 at #aa ,p4,m41 a quiv]+ la/+ two seconds 0 felt at ,inv]ness1 & a weak tremor1 accompani$ by s\nd1 at ,do*g>ro* at #a4ae ,a4,m4 on ,septemb] #ah?4 ,n9e m9utes lat]1 at #a4bd ,a4,m41 occurr$ ! pr9cipal e>?quake1 ! %ock ( :i* w\ld be call$ a /rong "o1 ev5 9 ,italy & ,japan4 ,,effects ,,( ,,! ,,%ock4 ,9 ,inv]ness1 ! damage to build+s1 ?\gh seldom s]i\s1 0 by no means inconsid]able4 ,"o brick build+ us$ z a smi?y 0 de/roy$1 sev]al *imneys or p>ts ( !m fell1 & _m *imney-cans 7 displac$ or ov]?r[n4 ,at ,do*g>ro* & o!r places )9 ! meizoseismal area1 walls 7 crack$1 *imneys ?r[n d[n1 & l9tels loos5$4 ,b1 = ?is c\ntry1 an unusual effect ( ! e>?quake 0 a long crack made 9 ! nor? bank ( ! ,cal$onian ,canal ne> ,do*g>ro* ,lo*s4 ,x occurr$ 9 ! middle ( ! t[+-pa?1 & c\ld be trac$ at int]vals = a di/ance ( #bjj y>ds to ! ea/ ( ! ,lo*s1 & #djj y>ds to ! we/1 be+ (t5 a m]e ?read1 & 9 no place m ?an half-an-in* wide4 ,soon aft] its =mation1 h[ev]1 ! fissure 0 oblit]at$ by heavy %[]s ( ra94 ,,isoseismal ,,l9es ,,& ,,di/urb$ ,,area4 ,! map 7,fig4 #fe7 %[s ! area ov] :i* ! e>?quake 0 p]ceptible4 ,! isoseismal l9es are drawn p>tly cont9u\s & p>tly dott$--cont9u\s :]e "s confid5ce c be plac$ 9 _! accuracy1 & dott$ :]e _! c\rse mu/ be reg>d$ z d\btful1 ow+ to ! r>ity or abs5ce ( obs]vations4 ,! inn]mo/ isoseismal 7%[n on a l>g] scale 9 ,fig4 #ff7 corresponds to ! int5sity #h ( ! ,rossi-,=el scale1 & includes ! places :]e ! %ock 0 /rong en\gh to cause slight /ructural damage to build+s4 ,x is elliptical 9 =m1 #ab miles long1 #g miles broad1 & #fg squ>e mile 9 area1 ) its c5tre at a po9t ab\t #a-a_/b mile ea/-nor?-ea/ ( ,do*g>ro*1 & its long] axis runn+ ,n4 #cc ,e4 & ,s4 #cc ,w4 ,illu/ration3 ,,fig4 #fe4--;,isoseismal l9es ( ! ,inv]ness e>?quake4 7,davison47 ,! rema9+ isoseismals are less accurately drawn1 ow+ to ! sc>city ( obs]vations made 9 ! we/ ( ,scotl&4 ,except t[>ds ! we/1 h[ev]1 ! c\rse laid d[n = ! isoseismal #g may be tru/$4 ,its l5g? is #ec-a_/b miles1 wid? #ce miles1 & area #a1ejj squ>e miles4 ,its long] axis is almo/ exactly p>allel to t ( ! prec$+ isoseismal1 b ! di/ance betwe5 ! two curves is #i miles on ! nor?-we/1 & #ad miles on ! s\?-ea/1 side4 ,! isoseismal #f is #aje miles long1 #hg miles wide1 & conta9s #g1cjj squ>e miles2 & ! isoseismal #e1 #aeg miles long1 #adc miles wide1 & ab\t #ag1jjj squ>e miles 9 area4 ,! isoseismal #d may be reg>d$ z ! b\nd>y ( ! di/urb$ area ( ! e>?quake1 =1 s f> z kn[n1 ! %ock 0 n notic$ at any po9t outside x4 ,t[>ds ! nor?1 x 0 felt at ,wick1 ,ca/let[n1 & o!r int]m$iate places2 t[>ds ! we/ at ,tob]mory 9 ! isl& ( ,mull2 &1 t[>ds ! s\?1 at ,skelmorlie 79 ,ayr%ire71 ,paisley1 ,belsyde 7ne> ,l9li?g[71 ,gullane 7ne> ,nor? ,b]wick71 & ,dunb>4 ,along ! ea/ coa/ ( ,scotl&1 betwe5 ,wick & ,dunb>1 !re are few places ( any size :]e ! %ock 0 n felt4 ,! di/urb$ area ( ! e>?quake is ?us #bae miles long f nor?-ea/ to s\?-we/1 #aih miles wide1 & conta9s ab\t #cc1jjj squ>e miles4 ,position ( ! ,orig9at+ ,fault4--,! only isoseismals :i* are drawn accurately en\gh to det]m9e ! e>?quake-fault are ! two inn] ones1 ^? m>k$ #h & #g2 b ^! are suffici5t = ! purpose4 ,x is cle>1 f ! direction ( _! long] axes1 t ! av]age direction ( ! fault mu/ be ,n4 #cc ,e4 & ,s4 #cc ,w4 ,aga91 ! isoseismals are f>!r ap>t t[>ds ! s\?-ea/ ?an t[>ds ! nor?-we/1 imply+ t ! fault hades to ! s\?-ea/4 ,la/ly1 z ! int5sity ( ! %ock is great] on ! side t[>ds :i* ! fault hades1 x foll[s t ! fault-l9e mu/ lie a %ort di/ance 7ab\t a mile or s7 on ! nor?-we/ side ( ! c5tre ( ! isoseismal #h4 ,n[1 ! great fault allud$ to above occupies almo/ exactly ! position indicat$ by ! seismic evid5ce4 ,its mean direction f ,t>bat ,ness to ,lo* ,l9nhe is ,n4 #ce ,e4 & ,s4 #ce ,w41 x hades to ! s\?-ea/1 & ! fault-l9e passes ?r\gh a po9t ab\t ?ree-qu>t]s ( a mile to ! nor?-we/ ( ! c5tre ( ! isoseismal #h 7,fig4 #ff74 ,!re c be little d\bt1 !re=e1 t ! e>?quake 0 caus$ by a slip ( ?is fault2 & ! evid5ce ( ! aft]-%ocks1 z w be se51 (f]s additional support to ?is conclusion4 ,! region 9 :i* ! slip took place may be det]m9$ r\ghly f ! position & =m ( ! inn]mo/ isoseismal4 ,its c5tre mu/ h be5 close to ! po9t m>k$ ,a 9 ,fig4 #ff1 :i* corresponds to a po9t ab\t #a-a_/b mile ea/-nor?-ea/ ( ,do*g>ro*4 ,9 a horizontal direction1 its l5g? mu/ h be5 at lea/ five or six miles2 o!rwise1 ! isoseismal #h w\ld h be5 less elongat$4 ,x mu/ !re=e h rea*$ f ab\t half-a-mile nor?-ea/ ( ,lo* ,ness to ab\t half-a-mile s\?-we/ ( ,inv]ness4 ,its wid?1 measur$ along ! dip ( ! fault-surface is unkn[n2 b ! small di/ance betwe5 ! c5tre ( ! isoseismal & ! fault-l9e %[s t ! pr9cipal movem5t took place at a dep? :i* 0 probably "u1 r ?an ov]1 "o mile4 ,,nature ,,( ,,! ,,%ock4 ,we come n[ to ! evid5ce af=d$ by ! nature ( ! %ock1 9 :i* !re 0 b little v>iation ?r\gh\t ! di/urb$ area4 ,at ,inv]ness1 a g5tle movem5t 0 fir/ felt1 foll[$ by an extraord9>y quiv]+1 :i* increas$ 9 =ce = two or ?ree seconds1 & !n decreas$ = two or ?ree seconds2 j z ! quiv]+ 0 ab\t to cease1 !re 0 a di/9ct lur* or heave1 aft] :i* ! vibration 0 mu* m sev]e ?an be=e & la/$ sev]al seconds long] ?an ! fir/ "p ( ! %ock4 ,dal>ossie lies ab\t f\rte5 miles s\?-ea/ ( ,inv]ness1 & "h ! fir/ indication 0 a l\d s\nd1 z ( an express tra91 com+ f ! ea/1 ru%+ close to1 & !n "u1 ! h\se2 ?is la/$ = a few seconds1 & t[>ds ! end ( x ! h\se vibrat$4 ,!n succe$$ an int]val ( quietness = ab\t a second1 foll[$ by a t]rific bur/ or cra%1 n unlike ! cra% ( a l\d ?und] peal1 ( ab\t two seconds' duration1 dur+ :i* ! h\se di/9ctly heav$ up once & !n sank back4 ,aft] ano!r brief int]val ( quietness1 !re 0 a l[ rumble1 l ! s\nd ( a dy+ peal ( ?und]4 ,x w be notic$1 9 ?is acc\nt1 t ! two p>ts ( ! %ock 7 no long] consecutive4 ,!re 0 a %ort int]val ( re/ betwe5 !m1 ! int]m$iate vibrations obs]v$ at ,inv]ness be+ too weak to be felt at ,dal>ossie4 ,/ill f>!r away1 ! ext9ction became m m>k$4 ,at ,ab]de51 = in/ance1 ! %ock consi/$ ( two p>ts1 ! fir/ a tremble1 foll[$1 aft] an int]val ( a few seconds1 by a sw++ movem5t ( long] duration ?an ! tremble4 ,9 all p>ts ( ! di/urb$ area1 ! %ock ma9ta9$ ! same "* ( division into two p>ts1 ! second ( :i* 0 ( great] duration & int5sity ?an ! fir/ & consi/$ ( vibrations ( long] p]iod4 ,a ph5om5on ( su* wide occurr5ce 0 cle>ly n due to local influ5ces4 ,x mu/ h be5 caus$ by two sep>ate initial impulses1 ! /rong] succe$+ ! o!r aft] an int]val ( a few seconds & tak+ place 9 ne>ly ! same region ( ! fault4#fg ,,s\nd-,,ph5om5a4 ,outside ! isoseismal #e1 !re are b few records ( ! e>?quake-s\nd2 b x 0 he>d fa9tly at ,skelmorlie 79 ,ayr%ire71 ,belsyde 7ne> ,l9li?g[71 & ,gullane 7ne> ,nor? ,b]wick74 ,t[>ds ! nor?1 x 0 n obs]v$ beyond ,wick & ,wa!n 79 ,cai?ness74 ,! b\nd>y ( ! s\nd-area _c be laid d[n ) any approa* to accuracy1 b x mu/ h includ$ a di/rict conta9+ ab\t #bg1jjj squ>e miles4 ,?r\gh\t ! :ole di/urb$ area1 #hd p] c5t4 ( ! obs]v]s he>d ! s\nd4 ,! p]c5tage v>ies 9 diff]5t c\nties1 f #ic 9 ,inv]ness-%ire to #gg 9 ! c\nties ( ,p]? & ,ab]de52 b ! records 9 ! m di/ant regions are too few to all[ ( ! con/ruction ( isac\/ic l9es4 ,9 its "*1 ! s\nd resembl$ t usually he>d ) /rong e>?quakes1 #ci p] c5t4 ( ! obs]v]s hav+ comp>$ x to pass+ waggons1 traction-eng9es1 etc41 #be p] c5t4 to ?und]1 #ad to w9d1 #h to loads ( /ones fall+1 #c to ! fall ( heavy bodies1 #d to explosions or ! fir+ ( heavy guns1 & #g p] c5t4 to miscellane\s s\nds4 ,! int5sity ( ! s\nd gradually dim9i%$ outw>ds f ! epic5tre1 & mo/ rapidly ne> ! isoseismal #g1 :i* ab\nds approximately ! area 9 :i* ! s\nd 0 v l\d f t 9 :i* x 0 di/9ctly fa9t]1 & also includes ne>ly all ! places at :i* l\d explosive cra%es 7 he>d ) ! /ronge/ vibrations4 ,9 ! "t-relations ( ! s\nd & %ock1 ! ,inv]ness e>?quake resembles ! ,h]e=d e>?quake ( #ahif4 ,! beg9n+ ( ! s\nd prec$$ t ( ! %ock 9 #gb p] c5t4 ( ! records1 co9cid$ ) x 9 #bj1 & foll[$ x 9 #h p] c5t42 ! epo* ( maximum int5sity ( ! s\nd prec$$ t ( ! %ock 9 #bj p] c5t4 ( ! records1 co9cid$ ) x 9 #gc1 & foll[$ x 9 #g p] c5t42 :ile ! end ( ! s\nd prec$$ t ( ! %ock 9 #ae p] c5t4 ( ! records1 co9cid$ ) x 9 #cd1 & foll[$ x 9 #eb p] c5t4 ,some:at simil> proportions hold ov] ! great] "p ( ! di/urb$ area1 ! p]c5tages be+ ne>ly ! same 9 ! c\nties ( ,inv]ness1 ,ross1 ,nairn1 ,elg91 ,banff1 & ! mo/ di/ant c\nties4 ,b 9 ,ab]de5%ire an exception occurs1 ! ?ree epo*s ( s\nd & %ock 9 mo/ cases co9cid+ ) "o ano!r4 ,! majority ( ! obs]vations 9 ?is c\nty come f ! s\!rn "p1 & ! l9e jo9+ ?is di/rict to ! epic5tre is ne>ly p]p5dicul> to ! l9e ( ! e>?quake-fault4 ,?is result has an important be>+ on ! orig9 ( ! s\nd-vibrations4 ,=1 if ! g5]al prec$5ce ( ! s\nd ) respect to ! %ock 7 due to its sup]ior velocity1 ! p]c5tage ( records 9 :i* ! beg9n+ ( ! s\nd prec$$ t ( ! %ock w\ld v>y only ) ! di/ance1 & n ) ! direction f ! orig94 ,inde$1 ) increas+ di/ance f ! orig91 ?is p]c5tage %\ld cont9ually approa* #ajj2 :ile t 9 :i* ! end ( ! s\nd foll[$ t ( ! %ock %\ld dim9i% to z]o4 ,!re is1 h[ev]1 no trace ( ei!r t5d5cy1 ! s\nd be+ he>d aft] ! %ock at places close to ! b\nd>y ( ! s\nd-area4 ,on ! o!r h&1 x ! s\nd-vibrations 7 to />t simultane\sly1 or ne>ly s1 f all p>ts ( ! focus1 b especially f its m>g9al regions1 !n1 9 ! great] "p ( ! di/urb$ area1 ! s\nd w\ld be he>d bo? be=e & aft] ! %ock2 = ! lat]al m>g9s ( ! focus w\ld be ! portions ne>e/ to1 & f>!r f1 mo/ obs]v]s2 :ile1 at places ne> ! l9e ?r\gh ! epic5tre at "r angles to ! e>?quake-fault1 ! ?ree pr9cipal epo*s ( ! s\nd & %ock %\ld approximately co9cide4 ,! inf]5ce t ! s\nd-vibrations he>d be=e & aft] ! %ock come f ! m>g9s ( ! focus is also support$ by ! obs]vations on ! relative duration ( ! s\nd & %ock4 ,if we take only ^? records :i* are free f d\bt1 9 #gh p] c5t4 ( ! total numb]1 ! duration ( ! s\nd 0 great] ?an t ( ! %ock2 :ile1 9 ,ab]de5%ire1 accord+ to #ic p] c5t4 ( ! obs]v]s1 ! durations ( s\nd & %ock 7 equal4 ,we may imag9e1 !n1 t ! slip )9 ! seismic focus w\ld be greate/ 9 a c5tral region1 & t x w\ld die outw>ds 9 all directions t[>ds ! edges4 ,! friction aris+ f ! slipp+ 9 ! c5tral region w\ld produce *iefly ! comp>atively l>ge oscillations t =m$ ! p]ceptible %ock2 ! evanesc5t creep )9 ! m>g9al regions w\ld produce ! small & rapid vibrations t 7 s5sible only z s\nd4 ,,orig9 ,,( ,,! ,,e>?quake4 ,:ile ! seismic evid5ce enables u to det]m9e ! surface-position & ! horizontal dim5sions ( ! seismic focus1 x un=tunately ?r[s no light :atev] on a po9t ( "s importance--namely1 ! direction ( ! movem5t :i* caus$ ! e>?quake4 ,we _c inf] f x :e!r x 0 ! rock on ! s\?-ea/ or nor?-we/ side ( ! fault t slipp$ or :e!r bo? sides slipp$ at once2 nor1 if t po9t _h be5 settl$1 d we "k if ! movem5t ( ! displac$ side 0 upw>d or d[nw>d4 ,9 ! =mation ( ! fault1 h[ev]1 x is cle> t ei!r ! s\?-ea/ side has be5 depress$ or ! nor?-we/ side elevat$2 &1 z ! b$ ( ,lo* ,ness is bel[ ! level ( ! sea1 t ! =m] movem5t has pr$om9at$4 ,if ! displacem5ts :i* gave rise to ! e>?quake 7 m]ely a cont9uation ( ! orig9al s]ies ( movem5ts--& ?is is1 to say ! lea/1 a v probable view to take--!n we may imag9e t1 = a di/ance ( five or six miles1 & at a dep? ( ab\t a mile or less1 !re 0 a sudd5 sag d[nw>ds ( ! rock on ! s\?-ea/ side ( ! fault ?r\gh a di/ance :i* p]haps 9 no "p exce$$ a fraction ( an in*4 ,fig4 #ff is an attempt to repres5t r\ghly ! displacem5t :i* caus$ ! pr9cipal e>?quake4 ,! diagram makes no pret5ce to accuracy1 & ! scale 9 ! v]tical direction is enorm\sly great]1 p]haps a hundr$ ?\s& times great]1 ?an t 9 ! horizontal direction4 ,! /raight l9e is suppos$ to repres5t a /raight l9e drawn be=e ! e>?quake on ! surface ( ! rock adjo9+ ! fault on ! s\?-ea/ side & at a dep? ( ab\t a mile1 & ! curve ! =m ( ! same l9e aft] ! e>?quake4 ,illu/ration3 ,,fig4 #ff4--;,diagram to illu/rate suppos$ fault-displacem5t caus+ ,inv]ness e>?quake4 ,! effect ( ?is great slip w\ld obvi\sly be to relieve ! /ress 9 ! c5tral region ,a1 & to increase x sudd5ly 9 ! p>ts d5ot$ by ! lett]s ,b & ,c4 ,x is1 !re=e1 9 ^! p>ts especially t we %\ld expect future slips to occur4 ,ea* slip w\ld ( c\rse give rise to an aft]-%ock1 & w\ld 9 l mann] result 9 an increase ( /ress 9 its own t]m9al regions1 ?\gh *iefly on ! side remote f ! c5tre ,a4 ,,! ,,aft]-,,%ocks ,,& ,,_! ,,orig94 ,x is difficult to =m any e/imate ( ! total numb] ( aft]-%ocks4 ,! li/1 compil$ f ! records ( c>eful obs]v]s only1 includes =ty-six %ocks & t5 e>?-s\nds1 ! la/ ( all occurr+ on ,novemb] #ba/4 ,b ! li/ is c]ta9ly incomplete4 ,x conta9s1 = in/ance1 only "o entry on ,septemb] #ah? betwe5 #c4ef & #i ,a4,m42 :]eas1 dur+ ! same int]val1 no few] ?an eighte5 slight %ocks 7 felt by "o obs]v] at ,do*g>ro*1 :ile ano!r ne> ,ald\rie e/imates ! numb] ( %ocks up to ,octob] #bcrd at ab\t sev5ty4 ,! total numb] probably did n fall %ort ( "o hundr$4 ,! majority 7 c]ta9ly v slight1 &1 at ano!r "t1 w\ld h>dly h attract$ any notice4 ,!re 71 h[ev]1 ?ree ( mu* great] importance ?an ! re/4 ,^! occurr$ on ,septemb] #ah? at #c4ef & #i ,a4,m41 & on ,septemb] #cj? at #c4ci ,a4,m4 ,! isoseismal l9es ( all ?ree are elongat$ ovals1 _! long] axes are p>allel to ! fault1 & _! c5tres lie on ! s\?-ea/ side ( ! fault-l9e4 ,! %ocks 7 !re=e evid5tly due to slips sev]al miles 9 l5g? along ! fault4 ,at pres5t1 we are conc]n$ m ) ! position ( _! epic5tres4 ,^! are indicat$ by ! dots lett]$ ,b1 ,c1 ,d 9 ,fig4 #fg2 ! dot m>k$ ,a d5ot+ ! c5tre ( ! pr9cipal e>?quake1 & ! cont9u\s l9e ! pa? ( ! fault4 ,?us1 )9 two & a half h\rs1 ! great slip 0 foll[$ by "o ) its c5tre at ,b1 ne> ! s\?-we/ m>g9 ( ! pr9cipal focus4 ,ab\t five h\rs lat]1 ! sc5e ( action 0 sudd5ly transf]r$ to a region ) its c5tre at ,c on ! nor?-ea/ m>g94 ,bo? slips affect$ a portion ( ! fault-surface sev]al miles 9 l5g?1 & mu/ !re=e h increas$ ! area ( displacem5t1 slightly t[>ds ! nor?-ea/ & consid]ably t[>ds ! s\?-we/4 ,only small movem5ts occurr$ dur+ ! next twelve days until #c4ci ,a4,m4 on ,septemb] #cj?1 :5 ano!r long slip took place1 ) its c5tre at ,d1 /ill f>!r to ! s\?-we/1 & !re=e aga9 ext5d+ ! area & am\nt ( displacem5t 9 ?is direction4 ,illu/ration3 ,,fig4 #fg4--,map ( epic5tres ( aft]-%ocks ( ,inv]ness e>?quakes4 7,davison47 ,turn+ n[ to ! weak] aft]-%ocks & e>?-s\nds1 we f9d !m affect+ *iefly ?ree regions ( ! fault4 ,"o ( ^! is close to ,do*g>ro*1 ano!r ne> ,inv]ness1 & ! ?ird betwe5 ,ald\rie & ,drumnadro*it2 ! effects ( ! slips 9 ! la/ two di/ricts be+1 z be=e1 to ext5d ! area ( displacem5t a %ort di/ance 7p]haps half a mile7 to ! nor?-ea/ & n less ?an six miles to ! s\?-we/ und]nea? ,lo* ,ness4 ,! unequal division ( ! aft]-%ocks betwe5 ! two sides ( ! pr9cipal c5tre 7,a1 ,fig4 #fg7 is v m>k$4 ,! positions ( ! epic5tres ( =ty-f\r %ocks & e>?-s\nds c be det]m9$ ) m or less accuracy1 &1 ( ^!1 only t5 lie to ! nor?-ea/ ( ! pr9cipal c5tre1 :ile ?irty-f\r lie to ! s\?-we/1 six or sev5 ( ! latt] be+ b5ea? ,lo* ,ness4 ,"o o!r po9t may be ref]r$ to be=e leav+ ^! m9or %ocks4 ,s f> z reg>ds ! /rong] %ocks1 !re 0 a cont9ual decrease 9 ! dep?s ( ! seismic foci4 ,?is is %[n by ! progressive approa* ( _! epic5tres t[>ds ! fault-l9e2 ! di/ances 9 ! ?ree *ief aft]-%ocks be+ #a4g1 #a4j1 & #j4e miles respectively2 & 9 "o ( ! late/ %ocks 7t ( ,octob] #ac? at #d4bd ,p4,m41 ,e1 ,fig4 #fg7 ! di/ance is no m ?an "o-t5? ( a mile4 ,! focus ( ?is %ock mu/1 inde$1 h be5 q close to ! surface ne> ,do*g>ro*4 ,?is con/ant dim9ution 9 ! dep? ( ! foci %[s t ! great slip 0 foll[$ by a sudd5 increase ( /ress upw>ds z well z lat]ally1 & expla9s :y t slip did n leave any p]ceptible trace1 ei!r z fault-sc>p or fissure1 at ! surface4 ,,sympa!tic ,,e>?quakes4 ,x is rem>kable t1 ( ! #ef record$ aft]-%ocks1 at lea/ six 7 felt or he>d only at ,dal>ossie & o!r places 9 ! valley ( ! ,f9dhorn1 a valley :i* lies ab\t #ac or #ad miles to ! s\?-ea/ ( ! great fault4 ,t !y _h no connection ) t fault is c]ta91 = two ( !m 7 s /rong t1 if !y 7 s connect$1 !y c\ld n h escap$ ! notice ( "o or m ( ! wat*ful obs]v]s betwe5 ,drumnadro*it & ,inv]ness4 ,! probable explanation ( ^! aft]-%ocks is t !y 7 due to slips ( a fault runn+ along ! ,f9dhorn valley2#fh & t ! great displacem5t ne> ,inv]ness on ,septemb] #ah? l$ to a sudd5 increase ( /ress )9 ! rocks = _m miles ar\nd1 :i*1 at & ne> ,dal>ossie1 0 suffici5t to precipitate ! slips ref]r$ to4 ,,conclusion4 ,at fir/ sight1 two e>?quakes c\ld h>dly be m unlike ?an ! ,japanese e>?quake ( #ahia & ! ,inv]ness e>?quake ( #aija4 ,9 ! rice-fields ( c5tral ,japan1 z we h se51 ! roads = _m leagues 7 edg$ ) ru9s1 ! fault-slip 0 prolong$ up to ! surface & visible z a sc>p =ty1 if n sev5ty1 miles 9 l5g?1 plots ( gr\nd 7 compress$ & _! b\nd>ies alt]$1 ! hillsides 7 scor$ by l&slips1 places c n[ be se5 f "o ano!r t =m]ly 7 hidd5 by a m\nta9 ridge1 & ! total numb] ( aft]-%ocks )9 little m ?an two ye>s am\nt$ to above ?ree ?\s&4 ,on ! o!r h&1 :5 we exam9e ! di/ribution ( ! aft]-%ocks 9 space1 we f9d t1 ?\gh no "p ( ! fault 0 exempt f slips1 !y fav\r$ ?ree regions 9 p>ticul>--"o1 ! mo/ important1 a c5tral region1 yet n co9cid5t ) t 9 :i* ! pr9cipal %ock 0 mo/ int5se2 & ! o!r two surr\nd+ ! extremities ( ! fault4 ,) ! lapse ( "t1 ! aft]-%ocks on ! :ole became weak] & occurr$ less frequ5tly1 & ! av]age dep? ( ! foci gradually dim9i%$4 ,moreov]1 9 two di/ricts di/ant =ty-five & fifty-five miles f ! fault1 ! frequ5cy ( ! %ocks dur+ ! mon? succe$+ ! e>?quake 0 sudd5ly increas$ to t5 & sixte5 times ! normal rate4 ,x is int]e/+ to notice s close a simil>ity 9 "*1 subsi/+ ) s va/ a diff]5ce 9 ! scale ( int5sity4 ,! id5tity ( ! p[]s at "w 9 %ap+ ! /ructure ( bo? isl&s ,is manife/4 ,9 ,japan1 we see ! m\nta9-mak+ =ces act+ ) viol5ce & produc+ effects t are only too app>5t to ! eye4 ,9 ,scotl&1 :atev] may h happ5$ 9 =m] geological epo*s1 ! *anges 9 surface-/ructure are n[ tak+ place ) almo/ inf9ite sl[ness1 & hundr$s or ?\s&s ( ye>s mu/ elapse be=e ,lo* ,ness makes any visible progress 9 its m>* t[>ds ! sea4 ,,ref]5ces4 #a4 ,,davison1 ,c4--,! ,h]e=d ,e>?quake ( ,decemb] #ag1 #ahif4 7,birm+ham1 #ahii47 #b4 ---- ,! ,inv]ness ,e>?quake ( ,sept4 #ah1 #aija1 & its accessory %ocks4 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 lviii41 #aijb1 pp4 #cgg-cig4 ,,footnotes3 #fa ,! /udy ( ! ,h]e=d e>?quake is bas$ on #b1ijb records1 com+ f #a1idc places2 t ( ! ,inv]ness e>?quake on #gaj records f #cha places4 #fb ,! di/urb$ area ( ! ,h]e=d e>?quake ( #ahif 0 probably great] ?an t ( any o!r ,briti% e>?quake ( ! n9ete5? c5tury2 t ( ! ,pembroke e>?quake ( #ahib be+ m ?an #ef1jjj squ>e miles1 ( ! ,pembroke e>?quake ( #ahic ab\t #fc1fjj squ>e miles1 :ile t ( ! ,essex e>?quake ( #ahhd 7a f> /rong] %ock 9 ! meizoseismal area7 is e/imat$ at ab\t #ej1jjj squ>e miles4 #fc ,! approximate circul>ity ( ! two out] isoseismals is due to ! fact t ! vibrations propagat$ to su* great di/ances are ^? :i* />t f ! comp>atively small c5tral region ( ! focus4 #fd ,! above /atem5t summ>ises ! evid5ce ( ! majority ( ! obs]v]s 9 ea* portion ( ! di/urb$ area4 ,9 ?is1 z 9 o!r simil> cases1 discrepancies 9 ! obs]vations are unavoidable2 b x is important to notice t !y are lea/ frequ5t 9 ! obs]vations evid5tly made ) ! greate/ c>e4 #fe ,except 9 ! case ( ,york%ire1 :]e ! ?ree ,rid+s are reg>d$ z sep>ate c\nties4 #ff ,! ,d]by e>?quake ( ,m>* #bd?1 #aijc1 0 also a tw9 e>?quake4 ,! c5tres ( ! two foci 7 situat$ ne> ,a%b\rne & ,wirkswor?1 above eight or n9e miles ap>t1 along a l9e runn+ ,n4 #cc ,e4 & ,s4 #cc ,w4 ,! two p>ts ( ! %ock coalesc$ along a rectil9eal b& ab\t five miles wide runn+ c5trally across ! l[] isoseismals 9 a direction at "r angles to _! long] axes4 ,! isac\/ic l9es are also elongat$ 9 ! direction ( ?is b&4 ,9 ?is case1 ! impulses at ! two foci mu/ h tak5 place at ! same in/ant4 7,qu>t4 ,j\rn4 ,geo4 ,soc41 vol4 lx41 #aijd1 pp4 #bae-bcb47 #fg ,if ! foci ( ! two impulses _h be5 deta*$1 !re w\ld1 ) s small an int]val betwe5 ! two p>ts1 h be5 a v>iation 9 ! nature ( ! %ock l t obs]v$ dur+ ! ,h]e=d e>?quake4 #fh ,?is "p ( ,inv]ness-%ire has n yet be5 mapp$ by ! ,geological ,survey1 b a fault is kn[n to exi/ 9 ! ,f9dhorn valley ne> ,drysa*an ,lodge1 :i* lies ab\t elev5 miles d[n ! valley f ,dal>ossie4 ,,*apt] ,,ix4 ,,! ,,indian ,,e>?quake ,,( ,,june #ab,,?1 #ahig4 ,v diff]5t f ! %ocks ( ,brita9 0 ! e>?quake t ov]:elm$ s l>ge a "p ( its great dep5d5cy on ,june #ab?1 #ahig--;an e>?quake :i*1 if x is n )\t a rival1 is c]ta9ly "o ( ! mo/ disa/r\s & mo/ widely-felt ( :i* we possess any record4 ,t x 0 ( ! fir/ magnitude 0 evid5t at once 9 ,calcutta f ! ext5sive injury to build+s1 & its inve/igation 0 und]tak5 )\t delay by ! memb]s ( ! ,geological ,survey ( ,india4 ,! f\r (fic]s :o 7 at ! headqu>t]s 9 ,calcutta 7 despat*$ to ! area ( greate/ damage1 lett]s & circul>s 7 di/ribut$ z widely z possible1 a l>ge numb] ( obs]v]s 7 induc$ to co-op]ate by keep+ records ( ! aft]-%ocks1 &1 lat] on1 dur+ ! cold wea!r ( #ahig-ih1 ,mr4 ,r4,d4 ,oldham1 "o ( ! sup]9t5d5ts ( ! ,survey1 made a t\r ?r\gh ! epic5tral di/rict4 ,to him1 moreov]1 fell ! mu* h>d] task ( discuss+ ! v num]\s obs]vations collect$ by himself & o!rs2 & ! lea/ t c be said ( ! valuable report prep>$ by him is t x is wor?y ( a great subject4 ,pr(essor ,omori also sp5t sev]al mon?s 9 /udy+ ! e>?quake on behalf ( ! ,japanese ,gov]nm5t2 b ! acc\nt1 :i* is writt5 9 8 own language1 un=tunately rema9s a seal$ book to we/]n seismologi/s4 ,illu/ration3 ,,fig4 #fh4--;,isoseismal ,l9es ( ,indian ,e>?quake4 7,oldham47 ,,isoseismal ,,l9es ,,& ,,di/urb$ ,,area4 ,9 ,fig4 #fh1 :i* %[s ! area di/urb$ by ! e>?quake1 ,mr4 ,oldham has drawn two s]ies ( curves4 ,9 ! abs5ce ( detail$ records ( ! int5sity--records t c\ld n h be5 obta9$ f "s p>ts ( ! di/urb$ area1 & w\ld h be5 difficult to procure 9 suffici5t numb] f o!rs--he has repres5t$ by ! dott$ curves a gr\p ( isoseismals 9 ! =m :i* he believes !y w\ld h assum$ _h ! e>?-waves be5 propagat$ 9 a homog5e\s m$ium4 ,! fir/ includes all places1 su* z ,%illong & ,goalp>a1 :]e ! de/ruction ( brick & /one build+s 0 practically univ]sal2 ! second1 ^?1 l ,d>jil+1 9 :i* damage to build+s 0 univ]sal & (t5 s]i\s2 ! ?ird1 places1 l ,calcutta1 :]e ! e>?quake 0 /rong en\gh to injure all or ne>ly all brick build+s4 ,inside ! f\r? isoseismal1 ! %ock 0 /rong en\gh to di/urb furniture & loose objects1 b n to cause m ?an slight damage2 )9 ! fif?1 x 0 g5]ally notic$2 &1 beyond ?is1 & z f> z ! six? isoseismal1 ! e>?quake 0 p]ceiv$ only by a small numb] ( s5sitive p]sons at re/4 ,! approximation ( ! curves t[>ds ! ea/ & s\?-ea/1 ,mr4 ,oldham believes to be p>tly real1 & n due to imp]fect in=mation4 ,! cont9u\s curves repres5t m closely ! actual v>iation ( int5sity4 ,! inn]mo/ curve ,a indicates ! probable b\nd>y ( ! epic5tral tract1 :i* is ab\t #bjj miles 9 l5g? & m ?an #fjjj squ>e miles 9 area4 ,?is w be ref]r$ to aft]w>ds 9 great] detail4 ,! next curve ,b b\nds ! region )9 :i* s]i\s damage to brick h\ses 0 common4 ,its irregul> c\rse is closely connect$ ) ! geological /ructure ( ! c\ntry1 & is due to ! fact1 ( :i* we h already met ) sev]al examples1 t e>?quakes are m de/ructive to h\ses built on alluvial gr\nd ?an to ^? f\nd$ on rock4 ,! area includ$ )9 ?is curve is n less ?an #ade1jjj squ>e miles2 &1 if we include ! p>ts f :i* reports 7 n obta9able1 x mu/ am\nt to ab\t #afj1jjj squ>e miles4 ,! curve ,c repres5ts ! b\nd>y ( ! di/urb$ area1 s f> z kn[n1 = ab\t "o-?ird ( ! area lies 9 regions f :i* no in=mation 0 procurable1 :ile ano!r ?ird is inhabit$ by ignorant & illit]ate tribes4 ,b1 not)/&+ ?is1 ! %ock is kn[n to h be5 felt ov] an area ( at lea/ #a1bjj1jjj squ>e miles4 ,if we include ! deta*$ region to ! we/1 ne> ,ahm$abad1 ! portion ( ! ,bay ( ,b5gal 9 :i* ! %ock w\ld h be5 felt _h ! sea be5 replac$ by l&1 & a l>ge "p ( ,?ibet or ,we/]n ,*9a1 f :i* no reports h come1 b 9 :i* ! %ock 0 c]ta9ly s5sible1 ?is e/imate1 great z x is1 mu/ be rais$ to ab\t #a1gej1jjj squ>e miles4#fi ,figures1 su* z ^? giv5 above1 convey b little idea ( ! va/ness ( ! area conc]n$4 ,transf]r+ !m to c\ntries ) :i* we are m famili>1 we may say t ! di/urb$ area 0 only a little less ?an half ! size ( ,europe2 ! region 9 :i* s]i\s damage occurr$ to masonry 0 m ?an twice z l>ge z ! :ole ( ,great ,brita92 :ile1 if ! c5tre ( ! epic5tral tract _h be5 9 ,birm+ham1 ne>ly e brick & /one build+ betwe5 ,york & ,exet] w\ld h be5 levell$ ) ! gr\nd4 ,,nature ,,( ,,! ,,%ock4 ,few & slight 7 ! =]unn]s ( ! greate/ ( mod]n e>?quakes4 ,e>ly 9 ,june1 fa9t tremors 7 felt by s5sitive p]sons at ,%illong4 ,o!rs at ! same place he>d a rumbl+ s\nd = t5 or fifte5 seconds be=e ! %ock began1 & at ,sil*> birds 7 se5 to rise sudd5ly f trees be=e ! movem5t became s5sible to man4 ,except = ^! almo/ imp]ceptible w>n+s1 ! e>?quake broke abruptly ov] ! :ole di/rict4 ,at #e4ae1 writes "o obs]v] at ,%illong1 a deep rumbl+ s\nd1 l ne> ?und] comm5c$1 app>5tly com+ f ! s\? or s\?-we/4444 ,! rumbl+ prec$$ ! %ock by ab\t two seconds 444 & ! %ock rea*$ its maximum viol5ce almo/ at once1 9 ! c\rse ( ! fir/ two or ?ree seconds4 ,! gr\nd began to rock viol5tly1 & 9 a few seconds x 0 impossible to /& upright1 & ,i _h to sit d[n sudd5ly on ! road4 ,! %ock 0 ( consid]able duration1 & ma9ta9$ r\ghly ! same am\nt ( viol5ce f ! beg9n+ to ! end4 ,x produc$ a v di/9ct s5sation ( sea-sickness4444 ,! feel+ 0 z if ! gr\nd 0 be+ viol5tly j]k$ backw>ds & =w>ds v rapidly1 e ?ird or f\r? j]k be+ ( great] scope ?an ! int]m$iate ones4 ,! surface ( ! gr\nd vibrat$ visibly 9 e direction1 z if x 0 made ( s(t jelly2 & long cracks appe>$ at once along ! road4444 ,! road is b\nd$ "h & !re by l[ banks ( e>?1 ab\t two feet high1 & ^! 7 all %ak5 d[n q flat4 ,! s*ool build+1 :i* 0 9 sight1 began to %ake at ! fir/ %ock1 & l>ge slabs ( pla/] fell f ! walls at once4 ,a few mom5ts aft]w>ds ! :ole build+ 0 ly+ flat1 ! walls collaps$1 & ! corrugat$ iron ro( ly+ b5t & brok5 on ! gr\nd4 ,a p9k cl\d ( pla/] & du/ 0 se5 hang+ ov] e h\se 9 ,%illong at ! end ( ! %ock4444 ,my impression at ! end ( ! %ock 0 t its duration 0 c]ta9ly "u "o m9ute1 & t x _h travell$ f s\? to nor?4444 ,! viol5ce ( ! %ock may be imag9$ :5 x is /at$ t ! :ole ( ! damage done 0 complet$ 9 ! fir/ t5 or fifte5 seconds ( ! %ock4 ,o!r e/imates ( ! duration are g5]ally high] ?an t giv5 above1 rang+ f ?ree to five or ev5 m m9utes at ,tura1 ,dhubri1 ,sil*>1 ,calcutta1 & o!r places4 ,9 "s cases1 x is possible t ! imm$iately succe$+ tremors 7 includ$ z "p ( ! great %ock2 b1 9 ! c5tral area1 x is probable t ! av]age duration ( ! %ock did n diff] mu* f ?ree or f\r m9utes4 ,9 ?is di/rict1 ! movem5t 0 mo/ complicat$4 ,*anges ( direction 7 frequ5tly notic$4 ,at ,sil*>1 = in/ance1 ! e>?quake began ) an undulatory movem5t f nor? to s\?1 l ! sw++ ( a susp5sion bridge2 x clos$ ) a motion l t ( a boat toss$ 9 a *oppy sea1 or by ! cross+ ( great waves :i*1 :atev] _! dom9ant direction may h be51 c]ta9ly did n travel f nor? to s\?4 ,! v]tical compon5t ( ! motion mu/ h be5 consid]able2 =1 at ,%illong1 loose /ones ly+ on ! roads 7 toss$ 9 ! air l peas on a drum1 ,b ?is 0 ev5 less pron\nc$ ?an ! horizontal movem5t1 ! range ( :i* 0 at lea/ eight or n9e in*es1 & dur+ :i* p felt z if !y 7 be+ %ak5 l a rat by a t]ri]4 ,! p]iod ( ^! vibrations 0 e/imat$ at ab\t a second4 ,z !y left ! c5tral region1 ! p]iod ( ! waves l5g!n$1 s t1 at a di/ance1 ! %ock no long] consi/$ ( %ort j]ks1 b became a g5tle rock+ motion1 caus+ 9 "s p a s5sation ( nausea4 ,at ,calcutta1 ! undulations 7 regul> & resembl$ ! roll+ ( a mighty %ip1 ! p]iod be+ betwe5 "o & two seconds4 ,at ,balasor1 ! motion 0 a long roll+ "o1 su* z w\ld be felt on ! deck ( a %ip 9 a fairly heavy sea2 &1 f>!r to ! s\? z f> z ! limit ( ! di/urb$ area1 ! same undulatory movem5ts 7 obs]v$1 gradually decreas+ 9 int5sity1 & usually comp>$ to ! easy motion ( a %ip 9 a g5tle sea4 ,visible ,e>?-,waves4--,a few examples h already be5 giv5 ( ! obs]vation ( visible waves on ! surface ( ! gr\nd4 ,!y 7 se5 at ,*>le/on dur+ ! e>?quake ( #ahhf 7p4 #aaj71 & at ,akasaka & o!r places 9 ! meizoseismal area dur+ ! ,japanese e>?quake ( #ahia 7p4 #ahf74 ,b !y 7 m ?an usually prom95t 9 ! ,indian e>?quake2 inde$1 mu* ( ! difficulty exp]i5c$ 9 /&+ dur+ ! %ock seems to h be5 due to ! passage ( ^! surface-waves4 ,at ,%illong1 accord+ to an obs]v] quot$ above 7p4 #bff71 ! surface ( ! gr\nd vibrat$ visibly 9 e direction1 z if x 7 made ( s(t jelly4 ,ano!r describes x z pres5t+ ! aspect ( a /orm-toss$ sea1 ) ?is diff]5ce t ! undulations 7 inf9itely m rapid ?an any se5 at sea4 ,ne> ,maimans+h1 e>?-waves 7 wat*$ approa*+1 exactly l roll]s on ! sea-coa/1 &1 z !y pass$1 ! obs]v]s _h a difficulty 9 /&+4 ,at ,nalb>i1 ! rice 9 ! fields c\ld be se5 ris+ & fall+ at int]vals dur+ ! transit ( ! waves4 ,9 ! ,assam valley1 ne> ,mangaldai1 !re 7 se5 waves com+ f opposite directions & meet+ 9 a great heap & !n fall+ back2 ea* "t ! waves seem$ to fall back ! gr\nd op5$ slightly1 & ea* "t !y met1 wat] & s& 7 ?r[n up to a height ( ab\t #ah in*es or s4 ,ev5 z f> z ,midnapur1 ! gr\nd 0 di/9ctly bill[y1 & at ,allahabad a s]ies ( waves 0 obs]v$ to cross ! gr\nd f s\?-s\?-we/ to nor?-nor?-ea/4 ,x is obvi\sly difficult to judge 9 any case ( ! magnitude ( su* waves4 ,9 ! epic5tral area1 ,mr4 ,oldham believes t1 on an av]age1 !y 7 probably ab\t ?irty feet long & "o foot 9 height1 ?\gh "s may h be5 bo? %ort] & high]4 ,^! movem5ts mu/ h be5 comp>atively sl[1 = _! progress c\ld be easily foll[$ by ! eye2 inde$1 _! rate1 z "o witness rem>ks1 ?\gh decid$ly fa/] ?an a man c\ld walk1 0 n s fa/ z he c\ld run4 ,,elem5ts ,,( ,,! ,,wave-,,motion4 ,9 8 /udy ( ! ,neapolitan e>?quake1 ,mallet %[$ h[ ! amplitude & maximum velocity ( ! vibrations c\ld be det]m9$ r\ghly f ! displacem5t1 projection1 or ov]?r[ ( v>i\s bodies by ! e>?quake4 ,some:at simil> me?ods 7 employ$ by ,mr4 ,oldham 9 ! abs5ce ( seismographs f ! epic5tral area4 ,8 results are ( c\rse only approximate1 b !y lead nev]!less to a conclusion ( great value & int]e/4 ,illu/ration3 ,,fig4 #fi4--,section ( ,tombs 9 ! ,cemet]y at ,*]rapunji4 7,oldham47 ,amplitude4--,! be/ measure ( ! amplitude 0 obta9$ at ! cemet]y at ,*]rapunji1 situat$ ne> ! s\!rn m>g9 ( ! epic5tral area4 ,"h 7 two oblong masonry tombs 7,fig4 #fi71 /&+ close toge!r ) _! long] axes po9t+ nor? & s\?4 ,_! inn] sides 7 p>tially de/roy$4 ,on ! out] sides1 !y are almo/ intact1 b ! tombs h be5 driv5 bodily d[n into ! gr\nd1 & on ei!r side to ea/ & we/1 !re is a depression ) a v]tical side p>allel to ! out] surface ( ! tomb & a smoo? flat bottom ov] :i* ! base ( ! tomb has slid4444 ,! edge ( ! we/]n depression has ! grass gr[+ undi/urb$ up to ! edge ( x1 & along ! edge small fragm5ts ( lime & pla/] %[ t ?is 0 orig9ally 9 contact ) ! edge ( ! tomb1 :i* has n[ mov$ away to a di/ance ( #ah in*es4 ,on ! ea/ ! edge ( ! depression is rais$ & ! grass & e>? =c$ upw>ds by ! ?ru/ ( ! tomb aga9/ x2 ! bread? ( ?is depression is #aj in*es4 ,dur+ ! movem5t ( ! gr\nd1 ! tombs1 ow+ to _! in]tia1 rema9$ comp>atively /ation>y1 & ! depressions 7 =m$ by ! backw>d & =w>d movem5t ( ! gr\nd aga9/ !m4 ,! movem5t on ! ea/ side 0 cle>ly arre/$ 9 "s mann]1 & ! range !re=e _c h be5 less ?an #aj in*es4 ,x may h be5 z mu* z #ah in*es1 & 0 probably1 9 ,mr4 ,oldham's op9ion1 ! mean ( ^! two am\nts--namely1 #ad in*es4 ,?is w\ld give an amplitude ( ab\t #g in*es1 a value :i* may be 9 excess ( ! av]age am\nt else:]e 9 ! di/rict1 z ! cemet]y is situat$ ne> ! edge ( a high s&/one sc>p4 ,at ,tura1 also )9 ! epic5tral area1 a range ( n less ?an #aj in*es 0 giv5 by ! slid+ ( a wood5 h\se ov] ! po/s on :i* x re/$4 ,six mon?s aft] ! %ock1 ,mr4 ,oldham frequ5tly notic$ vacant spaces f\r or five in*es across by ! side ( l>ge b\ld]s scatt]$ ov] ! ,khasi hills1 & he inf]s t ?r\gh\t ! :ole tract ly+ we/ ( ,%illong & ,gauhati1 z f> z ! hills ext5d1 & probably ov] a l>ge area ( ! pla9s besides1 ! amplitude ( ! wave-motion 0 n[h]e less ?an #c in*es1 :ile 9 _m places x 0 ov] #f in*es4 ,maximum ,velocity4--,! mo/ tru/wor?y measure ( ! maximum velocity are ^? obta9$ f ! projection ( bodies4 ,mr4 ,oldham selects ! foll[+ z mo/ des]v+ ( notice3--,at ,goalp>a1 an obelisk surm\nt+ a tomb 0 brok5 (f & ?r[n to "o side1 giv+ a maximum velocity ( n less ?an #aa feet p] second4 ,at ,gauhati1 ! cop+ ( a small gate-pill> 0 %ot (f & fell at a di/ance ( #d feet #d in*es f ! c5tre ( ! pill>2 9 ?is case ! maximum velocity mu/ h exce$$ #h feet p] second4 ,! highe/ velocity1 ( m ?an #af feet p] second1 0 measur$ at ,rambrai1 :]e a small gr\p ( monoli?s 7 %ot out ( ! gr\nd1 "o ( !m to a di/ance ( #f-a_/b feet4 ,la/ly1 at ,sil*>1 a bullet 0 project$ f ! corn] ( a wood5 po/1 act+ z a r\gh =m ( seismomet]1 f :i* a maximum velocity ( at lea/ #a-a_/b feet p] second 0 d$uc$4 ,maximum ,accel]ation4--,e/imates ( ! maximum horizontal accel]ation 7 made f #bh ov]?r[n pill>s by means ( ,pr(essor ,we/'s =mula 7p4 #ahd1 footnote74 ,! measures obta9$ at ! same place %[ "s v>iation1 b ,mr4 ,oldham consid]s z fair av]age values ^? ( #ad feet p] second p] second at ,goalp>a1 #ab at ,gauhati1 ,%illong1 & ,sylhet1 #aj at ,*]rapunji1 #i at ,dhubri1 & #d feet p] second p] second at ,sil*>4 ,( ! v]tical compon5t ( ! accel]ation1 n ev5 ! r\ghe/ num]ical e/imate c be =m$4 ,we "k1 h[ev]1 t at ,%illong1 ,gauhati1 & inde$ ?r\gh\t ! epic5tral area1 /ones 7 project$ upw>ds1 & ?is is evid5ce t ! v]tical compon5t 0 great] ?an t ( gravity--namely1 #cb feet p] second p] second4 ,viol5t z ! %ock 0 at ! places j m5tion$1 x mu/ h be5 /ill great] 9 c]ta9 p>ts ( ! epic5tral area4 ,at ,dilma1 9 ! ,g>o hills1 ! %ock seems to h be5 /rong en\gh to disable m52 &1 9 ! neighb\rhood ( ! faults t w be describ$ 9 a lat] section1 =e/ trees 7 snapp$ 9 two4 ,=tunately1 z ,mr4 ,oldham rem>ks1 !re 7 9 ^! di/ricts no t[ns or popul\s settlem5ts to feel ! full p[] ( ! e>?quake to de/roy4 ,anomalies 9 ! above ,measurem5ts4--,if ! movem5ts ( ! gr\nd foll[$ ! law ( simple h>monic motion1 any two ( ! f\r elem5ts 7p]iod1 amplitude1 maximum velocity1 & maximum accel]ation7 w\ld suffice to det]m9e ! o!rs 7p4 #d74 ,apply+ ! usual =mul to ! quantities obta9$ at ,gauhati--namely1 #h feet p] second = ! maximum velocity & #ab feet p] second p] second = ! maximum accel]ation1 x foll[s t ! amplitude w\ld be #e feet & ! p]iod #d seconds--values1 :i* are evid5tly inadmissible4 ,or1 tak+ ! maximum v]tical compon5t at #cb feet p] second p] second1 ! correspond+ values w\ld be #b feet & #a-a_/b seconds1 t ( ! amplitude be+ /ill too great4 ,aga91 at ,rambrai1 ! maximum velocity 0 f\nd to exce$ #af feet p] second4 ,! o!r elem5ts are unkn[n1 b1 if ! amplitude 7 "o foot1 ,mr4 ,oldham %[s t ! maximum accel]ation w\ld be #bef feet p] second p] second2 or1 tak+ ! amplitude at ! impossible am\nt ( two feet1 t ! maximum accel]ation w\ld be #abh feet p] second p] second4 ,x foll[s1 !re=e1 t only "p ( ! high velocities at ,rambrai & else:]e c be due to ! ela/ic waves provok$ by ! initial di/urbances4 ,! rema9+ portion mu/ be attribut$ to a bodily displacem5t ( ! e>?'s cru/ )9 ! epic5tral area--a displacem5t ( :i* ! fault-sc>ps & o!r di/ortions ( t region furni% ample evid5ce4 ,,s\nd-,,ph5om5a4 ,9 ! epic5tral area1 ! s\nd t accompani$ ! e>?quake 0 rem>kable = its extraord9>y l\dness4 ,at ,%illong1 ! cra% ( h\ses fall+ )9 ?irty y>ds 0 completely dr[n$ by ! ro> ( ! e>?quake4 ,! s\nd 0 g5]ally comp>$ to di/ant ?und]1 ! passage ( a tra9 or c>t1 etc42 b1 :atev] ! type may be1 x always implies a s\nd ( deep pit*1 close to ! l[] limit ( audibility--a cont9u\s rumbl+ or rattl+ noise1 z a rule gradually becom+ l\d] & !n dy+ away4 ,!re 0 ! usual conflict 9 ! evid5ce ( diff]5t obs]v]s due to ! dep? ( ! s\nd4 ,9 ,calcutta1 :i* lies well )9 ! s\nd-area1 "s p]sons ass]t$ t !y he>d a rumbl+ noise2 o!rs 7 positive t ! only noise 0 t caus$ by fall+ build+s & furniture4 ,"s1 aga91 notic$ t ! %ock 0 prec$$ by a l\d ro>2 :ile o!rs 7 c]ta9 t !re 0 no s\nd ( any k9d until ! e>?quake _h become sev]e4 ,z 9 ! case ( ! di/urb$ area1 x is impossible to def9e ! b\nd>y ( ! region ov] :i* ! s\nd 0 he>d4 ,l ! %ock1 also1 x seems to h be5 obs]v$ f>!r to ! we/ ?an t[>ds ! ea/4 ,leav+ out ( acc\nt records t are possibly d\btful1 ! s\nd 0 he>d = a di/ance ( #ccj miles to ! we/ & s\?-we/1 & #bij miles to ! ea/ ( ! epic5tral area--t is1 all[+ = ! dim5sions ( t area1 x mu/ h be5 p]ceptible ov] a region measur+ n less ?an #hjj miles f ea/ to we/4 ,,velocity ,,( ,,! ,,e>?-,,waves4 ,x is some:at d\btful :e!r a m accurate e/imate ( ! velocity is to be obta9$ f a viol5t e>?quake or f "o ( mod]ate int5sity4 ,9 ! =m] case1 ! va/ di/ances to :i* ! %ock is notic$ less5 ! effects ( errors 9 ! "t-det]m9ations1 b ?is advantage is to a great ext5t comp5sat$ by ! consid]able duration ( ! %ock & ! consequ5t unc]ta9ty :e!r all obs]v]s h tim$ ! same phase ( ! movem5t4 ,also1 9 ! ,indian e>?quake1 !re are fur!r s\rces ( error 9 ! v>iety ( /&>d times employ$ ?r\gh\t ! c\ntry & 9 ! magnitude ( ! epic5tral area4 ,( ! num]\s "t-records collect$ by ,mr4 ,oldham1 ! be/ are ^? :i* 7 obta9$ f a few self-record+ in/rum5ts1 f ! m busy telegraph (fices1 f ! l>g] railway /ations1 & 9 "s cases f private individuals4 ,all records 7 9 ! fir/ place subject$ to a rigid process ( selection2 a l>ge numb] 7 reject$ on v>i\s gr\nds1 & ^? only 7 reta9$ :i* bore int]nal evid5ce ( accuracy1 due ei!r to ! conditions ( ! report]'s occupation or to ! c>e tak5 by him to ensure exactness4 ,to gu>d aga9/ any unconsci\s bias 9 mak+ ! selection1 ?is process 0 c>ri$ out be=e ! di/ances 7 calculat$1 & ev5 be=e ! position ( ! epic5tral area 0 kn[n4 ,! b\nd>y ( ?is area is %[n by ! cont9u\s l9e ,a 9 ,fig4 #fh4 ,its greate/ l5g? be+ ab\t #bjj miles f ea/ to we/1 x is necess>y 9 ! fir/ place to fix ^u an equival5t c5tre )9 x1 :i* may be reg>d$ = ?is special purpose z ! po9t ( dep>ture ( ! e>?-waves4 ,! m natural c\rse p]haps w\ld be to assume ?is po9t to co9cide ) ! c5tre ( ! area4 ,b1 z ! rate at :i* ! initial movem5t spread ov] t area w\ld probably diff] little f ! velocity ( ! e>?-wave1 & z all ! "t-/ations lie t[>ds ! we/1 ,mr4 ,oldham reg>ds a po9t ne> ! we/]n b\nd>y ( ! area 79 lat4 #be #de' ,n4 & long4 #ij #ae' ,e47 z a suffici5tly exact approximation to ! position ( ! equival5t c5tre4 ,! ne>e/ place at :i* good "t-obs]vations 7 made is ,calcutta1 di/ant #bee4e miles f ! assum$ c5tre4 ,"o is indicat$ on ! record+ tide-gauge by a sudd5 rise ( ! wat]1 :ile ! o!rs 7 obta9$ f ! c5tral telegraph (fice1 ! t]m9al railway /ations1 & f two c>eful read+s by int]e/$ obs]v]s4 ,!y v>y f #d;h4 #bgm4 #js4 to #d;h4 #bhm4 #cgs4 ,p4,m41 all be+ liable to an error ( half-a-m9ute4 ,! ari?metic mean = ! beg9n+ ( ! %ock is #d;h4 #bgm4 #dis41 & ?is is probably z accurate an e/imate z ! conditions all[4#gj ,bombay lies outside ! di/urb$ area1 #abjh4c miles f ! equival5t c5tre2 &1 = ! "t ( arrival 9 t city1 we h to dep5d on ! records ( ! b>ograph & ! ?ree magnetographs4 ,! horizontal =ce magnet 0 set 9 motion two & a half m9utes be=e ! o!rs1 no d\bt by ! advance tremors4 ,! times giv5 by ! b>ograph & ! v]tical =ce-in/rum5t diff] by only "o m9ute1 & ! be/ result seems to be t obta9$ by tak+ _! mean--namely1 #d;h4 #cem4 #dcs41 :i* is probably accurate to )9 a m9ute4 ,assum+1 !n1 t ! "t-int]val betwe5 ,calcutta & ,bombay does n err by m ?an half-a-m9ute1 x foll[s t ! int]v5+ velocity mu/ lie betwe5 #b4h & #c4b kilometres p] second1 its probable value be+ #c kilometres1 or #b miles1 p] second4 ,! rema9+ records1 :i* are ( less value ?an ^? obta9$ 9 ^! cities1 fall into two gr\ps1 ! fir/ consi/+ ( a numb] ( /ations along a l9e runn+ nor? & s\? betwe5 ,calcutta & ,d>jil+ or )9 a hundr$ miles on ei!r side ( ! same1 & ! second a long s]ies ( /ations cross+ ,nor!rn ,india 9 a ne>ly we/]ly direction4 ,! obs]vations made at ! ,burmese /ations 7 un=tunately affect$ by an error aris+ f ! ret>dation ( ! ,madras "t-signals ?r\gh frequ5t repetition along ! l9e4 ,illu/ration3 ,,fig4 #gj4--,"t-curve ( ,indian e>?quake4 7,oldham47 ,individually1 ^! records are n exact en\gh to be us$ 9 det]m9+ ! velocity1 b !y may be employ$ collectively = ! con/ruction ( ! "t-curve 9 ,fig4 #gj4 ,9 ?is diagram1 di/ances 9 hundr$s ( miles f ! equival5t c5tre are repres5t$ along ! horizontal l9e1 & ! "t ( occurr5ce 9 m9utes pa/ #d ,p4,m4 along ! p]p5dicul> l9e4 ,! small circles repres5t ! obs]vations at ,calcutta & ,bombay1 ! dots ^? at places ly+ ne>ly we/ ( ! orig91 & ! crosses ^? at places situat$ to ! s\? or nor?-we/4 ,! cont9u\s curve passes 9 an av]age mann] ?r\gh ! s]ies ( po9ts1 & probably does n diff] mu* f ! true curve ( ! "t ( arrival ( ! %ock at diff]5t places4 ,! curve1 x w be notic$1 is at fir/ concave1 & aft]w>ds convex1 upw>ds2 indicat+ t ! times requir$ to trav]se successive equal di/ances at fir/ increas$1 & !n decreas$4 ,?us1 if ! curve is an accurate repres5tation ( ! facts1 x w\ld foll[ t ! surface-velocity 0 subject to a cont9ual decrease outw>ds f ! c5tre1 until x 0 a m9imum at a di/ance ( ab\t #bhj miles1 aft] :i* x increas$4 ,! deviation ( ! curve f a /raight l9e is1 h[ev]1 s slight t we _c feel mu* confid5ce 9 ?is conclusion4 ,if we jo9 ! po9ts correspond+ to ,calcutta & ,bombay by a /raight l9e 7drawn dott$ 9 ,fig4 #gj71 x does n 9 any "p v>y f ! cont9u\s l9e by a di/ance equival5t to m ?an half-a-m9ute4 ,inde$1 if a v few discordant records are exclud$1 & if less weight is giv5 to ^? times :i* are multiples ( five m9utes1 ! /raight l9e repres5ts ! mean q z fairly z ! curv$ l9e does2 & t ?is is ! m probable int]pretation w appe> f ! obs]vations on ! unfelt e>?quake describ$ 9 ! next section4 ,we may !re=e conclude t ! e>?-waves travell$ along ! surface at an approximately uni=m rate ( #c kilometres p] second1 or ab\t #abj miles a m9ute--a result :i* ,mr4 ,oldham consid]s may be accept$ z accurate to )9 five p] c5t4 ,if ! two "t-curves 9 ,fig4 #gj are cont9u$ to ! "r until !y meet ! "t-scale1 x w be se5 t !y int]sect x ne> ! po9t correspond+ to #d4bf ,p4,m41 imply+ t ?is w\ld be approximately ! "t at :i* ! %ock 0 felt )9 ! epic5tral area4 ,?is agrees closely ) ! obs]v$ times ( ab\t #d4be at ,p>batipur & ,ku* ,bih>1 #d4bf at ,siliguri1 & #d4bg at ,%illong & ,goalp>a2 & x is probable t ! error is n m ?an a qu>t] ( a m9ute 9 defect or half-a-m9ute 9 excess4 ,?us1 ! "t ( arrival ( ! fir/ s5sible waves at ! surface w\ld lie betwe5 #d;h4 #bem4 #des41 & #d;h4 #bfm4 #cjs4 ,p4,m41 ,madras "t1 or betwe5 #aa;h4 #dm4 #des4 & #aa;h4 #em4 #cjs4 ,a4,m41 ,gre5wi* mean "t4 ,,! ,,unfelt ,,e>?quake4 ,( ! cr[d ( vibrations t agitate ! gr\nd dur+ an e>?quake1 "p only comb9e to =m ! p]ceptible %ock4 ,"s are ins5sible ow+ to _! small amplitude1 o!rs to ! sl[ness ( ! motion4 ,an int]e/+ obs]vation belong+ to ! latt] class 0 made by an eng9e] ne> ,midnapur1 a place :i* lies j )9 ! area ( damage4 ,at ! "t ( ! e>?quake1 he 0 tak+ levels on a railway bank1 & 0 ab\t to take a read+ :5 he notic$ ! bubble ( ! level oscillat+4 ,9 five or t5 seconds ! %ak+ began & appe>$ to la/ ?ree or f\r m9utes2 b1 = m ?an five m9utes aft] x _h app>5tly ceas$1 ! level %[$ t ! gr\nd cont9u$ to rock4 ,aga91 9 ,burmah1 at a place n9ete5 miles ea/ ( ,tagaung & close to ! bord] ( ! di/urb$ area1 ! wat] 9 a %all[ tank1 ab\t #cjj y>ds 9 l5g?1 0 se5 lapp+ up aga9/ ! side 9 a mann] t 0 at fir/ attribut$ to elephants ba?+4 ,no %ock 0 felt1 b ! %ak+ ( ! trees at ! same "t %[$ t ! di/urbance 0 due to ! e>?quake4 ,f> beyond ! limits ( ! di/urb$ area1 h[ev]1 ! e>?quake 0 record$ by _m ( ! delicate in/rum5ts :i* h be5 employ$ dur+ ! la/ few ye>s = ! regi/ration ( di/ant %ocks4 ,among ! m important ( ^! in/rum5ts are long v]tical p5dulums1 horizontal p5dulums ( v>i\s =ms1 & magnetographs4 ,9 ! v]tical1 & "s ( ! horizontal1 p5dulums1 especially 9 ^? us$ 9 ! ,italian obs]vatories1 ! masses c>ri$ are heavy1 & ! movem5ts ( ! gr\nd are magnifi$ by lightly-balanc$ lev]s end+ 9 po9ts :i* trace _! records on b&s ( smok$ pap] driv5 by clockwork4 ,9 ! o!r horizontal p5dulums & 9 ! magnetographs1 ! me?od ( regi/ration is photographic4 ,! pap] requir$ = ! me*anical records be+ inexp5sive1 a high velocity 7half-an-in* or m p] m9ute7 c be giv5 to x1 & ! result+ diagrams are op5 & detail$4 ,! ,italian in/rum5ts also respond m readily ?an ! o!rs to ! e>li] & slight] tremors3 :ile ! app>atus 9 :i* photographic me?ods are us$ are sometimes s viol5tly di/urb$ by ! lat] undulations t ! spot ( light fails to leave any trace on ! photographic pap]4 ,x is !re=e f ! ,italian obs]vatories t ! m int]e/+ records come4 ,"o ( ^!1 giv5 by a horizontal p5dulum at ,rocca di ,papa ne> ,rome1 is reproduc$ 9 ,fig4 #ga2 :ile ! curve ( ! bifil> p5dulum at ,ed9burgh 7,fig4 #gb7 is a good example ( ^? obta9$ by ! photographic me?od ( regi/ration4#ga ,all ov] ,italy1 f ,is*ia & ,catania 9 ! s\? to ,pavia 9 ! nor?1 ! diff]5t in/rum5ts employ$ began1 "o aft] ! o!r1 to write _! records ( ! movem5t z ! unfelt e>?-waves sp$ outw>ds f ! c5tre4 ,italy pass$1 ! tale 0 tak5 up by magnetographs at ,potsdam & ,wilhelm%av51 ,pawlovsk 7ne> ,/4 ,pet]sburg71 ,cop5hag51 ,utre*t1 & ,p>c ,/4 ,maur 7ne> ,p>is72 by horizontal p5dulums at ,/rassburg & ,%ide 79 ! ,isle ( ,wight71 & by a bifil> p5dulum at ,ed9burgh4 ,%ide is #d1hia miles f ! c5tre ( di/urbance1 b1 z we %all see1 ! movem5t c\ld be trac$ = a di/ance great] ev5 ?an ?is4 ,illu/ration3 ,,fig4 #ga4--,seismographic ,record ( ,indian ,e>?quake at ,rocca di ,papa4 7,cancani47 ,9 ! m complete records1 & especially 9 ^? giv5 by ! ,italian app>atus1 ,mr4 ,oldham di/+ui%es ?ree phases ( motion4 ,! fir/ consi/s ( rapid & ne>ly horizontal movem5ts ( ! gr\nd4 ,9 ,italy1 x beg9s at ab\t #aa4ag ,a4,m4--t is1 ab\t #ab-a_/b m9utes aft] ! comm5cem5t ( ! %ock at ! epic5tre 7,fig4 #ga1 a74 ,)\t any break 9 ! movem5t1 & aft] a fur!r int]val ( ab\t #h-a_/b m9utes1 ! second phase beg9s2 ! vibrations are simil> to ! prec$+1 b !y are l>g] & m op51 & are accompani$ by an unmi/akable tilt+ ( ! surface ( ! gr\nd 7,fig4 #ga1 b74 ,la/ly1 aft] ! lapse ( ab\t tw5ty m9utes m1 ! second phase gives place1 )\t int]ruption1 to ! ?ird 7,fig4 #ga1 c71#gb consi/+ ( well-m>k$ sl[ undulations1 :i* h be5 aptly comp>$ by ,pr(essor ,milne to ! movem5ts caus$ by an ocean-swell4 ,z !y travell$ across ,europe1 ! surface ( ! gr\nd 0 ?r[n into a s]ies ( flat waves1 #cd miles 9 l5g?1 & #bj in*es 9 maximum height1 ! complete p]iod ( ea* wave be+ #bb seconds4 ,?is phase is by f> ! longe/ ( ! ?ree2 9 ! m s5sitive in/rum5ts1 two or ?ree h\rs elaps$ be=e _! traces ceas$ to %[ any sign ( movem5t4 ,illu/ration3 ,,fig4 #gb4--,seismographic ,record ( ,indian ,e>?quake at ,ed9burgh4 7,hea?47 ,kn[+ ! di/ances ( ! diff]5t obs]vatories f ! epic5tre1 & ! times tak5 by ea* phase to rea* !m1 we c =m "s idea ( ! rates at :i* !y travell$4 ,if ! e>ly tremors mov$ 9 /raight l9es1 _! mean velocity = ! fir/ phase 0 #i4j1 & = ! second #e4c1 kilometres p] second2 b1 if !y mov$ along curv$ pa?s ?r\gh ! body ( ! e>?1 _! mean velocities mu/ h exce$$ ^! am\nts4 ,= ! fir/ undulations ( ! ?ird phase1 ! velocity w\ld be #b4i kilometres p] second if !y travell$ along /raight l9es1 & #c4j kilometres p] second if !y 7 conf9$ to ! surface ( ! e>?4 ,! exi/5ce ( ! second phase 0 notic$ = ! fir/ "t by ,mr4 ,oldham 9 ! records ( ! ,indian e>?quake1 b he has s9ce detect$ x 9 ^? ( o!r %ocks4 ,he believes1 9 common ) mo/ seismologi/s1 t ! fir/ phase corresponds to waves ( ela/ic compression1 or longitud9al waves1 travell+ ?r\gh ! body ( ! e>?2 & ! second phase he attributes to waves ( ela/ic di/ortion1 or transv]sal waves1 travell+ 9 ! same way1 9 :i* ! p>ticles move at "r angles to ! direction 9 :i* ! wave travels1 ?us caus+ a slight tilt+ ( ! surface4 ,x is probable t ! waves ( bo? phases move along curv$1 r ?an /raight1 l9es ?r\gh ! e>?1 t ! curves are concave t[>ds ! surface1 & t ! velocity ( ! waves increases ) ! dep? ( _! pa? bel[ ! surface4 ,on ! o!r h&1 ! surface-velocity ( ! fir/ undulations ( ! ?ird phase is practically con/ant = all di/ances f ! epic5tre1 &1 9 ! case ( ! ,indian e>?quake1 x agrees almo/ exactly ) t obta9$ = ! velocity )9 ! di/urb$ area1 & z f> z ,bombay4 ,x is !re=e difficult to resi/ ! conclusion t ! ?ird phase consi/s ( undulations :i* travel along ! surface ( ! e>?4 ,div]g+ 9 two dim5sions only1 !y fade away mu* m sl[ly ?an ! vibrations ( ! o!r two phases4 ,we may ?us imag9e ^! surface-undulations spe$+ outw>ds f ! epic5tre 9 ev]-wid5+ circles until !y h pass$ ov] a qu>t]-circumf]5ce ( ! e>?1 :5 !y %\ld beg9 to conv]ge t[>ds ! antipodes4 ,"h !y %\ld cross ea* o!r1 & aga9 spread out z circul> waves1 once m 9 _! c\rse pass+ ! same obs]vatories :]e !y 7 fir/ record$1 b 9 ! opposite ord]4 ,x has be5 res]v$ = ! mo/ viol5t e>?quake ( mod]n times to v]ify ?is int]e/+ conclusion4 ,fa9t1 b decid$1 are ! traces ( ! second cross+4 ,at ,ed9burgh1 !y occur at #b4f ,p4,m41 at ab\t ! same "t at ,%ide1 at ,leghorn #b4aj1 ,catania #b4ab-c_/d1 :ile at ,is*ia !re are sev]al movem5ts betwe5 #b & #c ,p4,m4 ,at ,rocca di ,papa1 ne> ,rome1 ! "t is slightly e>li]1 b ! undulations1 l ^? at ! fir/ cross+1 h a complete p]iod ( ab\t #bj seconds4 ,! di/ances trav]s$ by ! waves are m ?an #bj1jjj1 in/ead ( less ?an #ejjj miles2 b ! mean velocity ) :i* !y travell$ is almo/ exactly ! same z at fir/--namely1 #b4ie kilometres p] second4 ,,e>?-,,fissures1 ,,s&-,,v5ts1 ,,etc4 ,e>?-,fissures4--,among ! sup]ficial effects ( ! e>?quake1 none take a m important place ?an ! fissures =m$ 9 alluvial pla9s4 ,n only 7 !y rem>kably abundant1 m s ?an 9 any o!r kn[n e>?quake1 b !y occurr$ ov] an unusually wide area4 ,:]ev] ! necess>y conditions prevail$1 !y 7 f\nd to be num]\s ov] a di/rict b\nd$ approximately by ! isoseismal #a 7,fig4 #fh71 & measur+ ab\t #djj miles f ea/ to we/1 & ab\t #cjj miles f nor? to s\?2 & !y 7 pres5t1 ?\gh 9 small] numb]s1 ov] an area ne>ly #fjj miles long 9 an ea/-nor?-ea/ & we/-s\?-we/ direction4 ,!y 7 naturally m frequ5t ne> riv]-*annels & res]voirs1 on acc\nt ( ! abs5ce ( lat]al support1 & z a rule 7 p>allel to ! edge ( ! bank1 a few hundr$ y>ds 9 l5g?1 & 9 wid? v>y+ f "s in*es to f\r or five feet4 ,fissures 9 su* positions are =m$ ) e viol5t e>?quake1 & ev5 ) "s ( ^? m mod]ate %ocks t visit ! ,briti% ,isl&s 7see p4 #bdg74 ,b an int]e/+ po9t e/abli%$ by ! ,indian e>?quake is t !y also occurr$ at a di/ance f any wat]-*annel or excavation1 (t5 runn+ p>allel to1 & along ei!r side (1 a road or embankm5t4 ,9 o!r situations1 !y %[$ a di/9ct t5d5cy to range !mselves p>allel to "o ano!r2 &1 9 ^! cases1 x is possible t _! =mation 0 connect$ ) ! passage ( ! visible surface-waves4 ,9 an acc\nt already quot$ 7p4 #bdg71 x is /at$ t ^! waves came f opposite directions & t1 z !y sep>at$ aft] meet+1 ! gr\nd op5$ slightly4 ,among ! ,khasi & ,g>o hills 7see ,fig4 #ge71 :]ev] ! alluvium ( ! pla9s runs up to ! foot ( ! hills1 ano!r =m ( fissure1 repres5t$ 9 ,fig4 #gc1 0 con/antly notic$4 ,close to ! junction1 !re 0 a sudd5 drop1 z at a1 ( f "o to five feet1 ! v]tical face hav+ ! appe>ance ( a fault1 b di/+ui%$ f "o by foll[+ ! w9d+s ( ! hills4 ,!n came a depress$ b& b1 f t5 to tw5ty feet wide1 & outside ?is a l[ r\nd$ ridge c rais$ above its =m] level1 & m]g+ beyond at d into ! undi/urb$ pla94 ,:5 ,mr4 ,oldham visit$ ! di/rict 9 ,m>* #ahih1 ! natives _h flood$ ! rice-fields1 & ! features describ$ 7 cle>ly depict$ by ! ga!r+ ( ! wat] 9 ! depression & ! isolation ( ! ridge4 ,illu/ration3 ,,fig4 #gc4--;,displacem5t ( alluvium at foot ( a hill4 7,oldham47 ,! explanation ( ^! peculi>ities is evid5tly t giv5 by ,mr4 ,oldham4 ,dur+ ! passage ( repeat$ waves ( compression1 ! ?ru/ ( ! hill & pla9 aga9/ "o ano!r caus$ ! heap+ up ( ! alluvium 9 ! ridge c2 :ile ! return movem5ts result$ 9 ! te>+ ( ! alluvium away f ! hillside1 leav+ ! sc>p a & ! depression b4 ,displacem5ts ( ,alluvium4--,_m o!r rem>kable evid5ces ( compression 7 obs]v$4 ,telegraph po/s1 orig9ally set up 9 a /raight l9e1 7 displac$1 occasionally z mu* z t5 or fifte5 feet2 sometimes )\t any app>5t connection ) neighb\r+ riv]-*annels4 ,9 "o "p ( ! ,assam-,b5gal ,railway1 = ne>ly half a mile1 ! :ole embankm5t1 includ+ borr[-pits & trees on ei!r side1 0 %ift$ lat]ally )\t any sign ( wr5*+ f ! adjo9+ gr\nd1 ! maximum di/ance am\nt+ to #f-c_/d feet4 ,z ! displacem5t took place p>allel to ! only riv]-c\rse 9 ! neighb\rhood1 ,mr4 ,oldham attributes x to ! slid+ ( ! surface-lay]s ov] "s yield+ b$ b5ea?4 ,aga91 ?r\gh\t l>ge areas ( ,nor!rn ,b5gal1 ,l[] ,assam1 & ,maimans+h1 rice-fields1 :i* _h be5 c>efully levell$ s t !y might be uni=mly flood$1 7 ?r[n into g5tle undulations1 ! cre/s ( :i* 7 occasionally two or ?ree feet above ! holl[s4 ,! pi]s ( bridges 7 also mov$ p>allel to1 z well z t[>ds1 ! /reams1 %[+ t ! displacem5ts ext5d$ to ! dep? ( ! f\ndations4 ,! buckl+ ( railway l9es 0 (t5 viol5t & took place ov] a l>ge area4 ,9 ! ,*>le/on e>?quake1 e su* b5d 0 accompani$ by a correspond+ ext5sion else:]e 7p4 #aac72 b1 9 ! ,balu*i/an e>?quake ( #ahib1 ! neighb\r+ fi%-jo9ts 7 jamm$ up tight4#gc ,9 ! "o case1 !re 0 m]ely local compression2 9 ! o!r1 a p]man5t displacem5t ( ! e>?'s cru/4 ,! di/ortion ( ! ,indian l9es seems to belong to ! =m] class4 ,repairs 7 ( c\rse g5]ally made )\t delay2 b all ! in=mation t c\ld be obta9$ on ?is po9t %[$ t ! compression caus+ ! crumpl+ ( ! l9es 0 accompani$ by a comp5sat+ expansion1 g5]ally at a di/ance ( ab\t #cjj y>ds4 ,s&-,v5ts4--,%ortly aft] ! e>?quake1 l>ge quantities ( wat] & s& issu$ f fissures 9 ! gr\nd4 ,at ,dhubri1 innum]able jets ( wat]1 l f\nta9s play+1 sp\t$ up to heights v>y+ f #ah in*es to q #c-a_/b or #d feet4 ,:]ev] ?is _h occurr$1 ! l& 0 aft]w>ds se5 to occupy a s&y circle ) a depression 9 its c5tre4 ,^! circles rang$ f #b to #f & #h feet 9 diamet]1 & 7 to be se5 all ov] ! c\ntry4 ,9 "s places1 sev]al 7 q close toge!r2 9 o!rs !y 7 at a di/ance ( sev]al y>ds4 ,ne> ,maimans+h1 !y seem to h be5 almo/ z num]\s1 fifty-two1 ( f\r feet & less 9 diamet]1 be+ c\nt$ )9 an area #ajj y>ds long & ab\t #bj feet wide4 ,! s& & wat] 7 eject$ f ! v5ts ) "s =ce4 ,a few obs]v]s e/imat$ ! height ( ! sp\ts at ab\t #ab feet1 b ?is probably ref]s to /ray spla%es4 ,x is cle>1 h[ev]1 t ! s& & wat] 7 =c$ n only up to ! surface1 b ev5 9 a cont9u\s /ream to heights ( f two to t5 feet above x4 ,9 _m di/ricts1 trunks ( trees or lumps ( coal & fossil res9 7 wa%$ up ) ! wat]1 & ev51 9 "o or two cases1 pebbles ( h>d rock weigh+ z mu* z half-a-p\nd4 ,! orig9 ( ! s&-v5ts is to be s\ght 9 ! pres5ce ( a wat]-be>+ b$ situat$ n f> bel[ ! surface4 ,9 ! c5tral area1 :]e !re 0 a m>k$ v]tical compon5t 9 ! motion1 ?is b$ dur+ ! e>?quake 0 compress$ betwe5 ^? above & bel[ x1 & ! result+ pressure 0 9 places suffici5t to =ce ! wat] & s&1 ?r\gh ! fissures =m$ by ! e>?quake1 up to & beyond ! surface4 ,! gradual settl+ ( ! upp] lay]1 cut up by ! fissures1 into ! und]ly+ quicks&1 prolong$ ! process = "s "t aft] ! %ock 0 ov]2 &1 :5 ! pressure 0 at la/ reliev$1 "s ( ! wat] 0 suck$ back & s produc$ ! crat]i=m holl[s4 ,rise ( ,riv]-,b$s1 etc4--,ov] a l>ge area1 riv]-*annels1 tanks1 wells1 etc41 7 fill$ up1 p>tly by ! outp\r+ ( ! s& f v5ts1 b *iefly1 z %[n by ! =c+ up ( ! c5tral pi]s ( bridges1 by ! elevation ( ! b$s ( ! excavations4 ,9 ! l[l&s :i* lie betwe5 ! ,g>o hills & ! ,brahmaputra1 !re 7 num]\s *annels f #ae to #bj feet 9 dep?1 ! b$s ( :i* 7 press$ up until !y became level ) ! banks1 :ile a comp5sat+ subsid5ce took place close to ! /reams on ei!r side4 ,! g5]al t5d5cy ( ! e>?quake 0 ?us to oblit]ate ! surface inequalities1 s t1 :5 ! riv]s rose lat] on1 ! di/rict 0 ext5sively flood$4 ,besides ^! def]r$ floods1 !re occurr$ imm$iately aft] ! e>?quake a sudd5 rise 9 _m riv]s1 am\nt+ to f two to t5 feet1 foll[$ by a gradual decl9e to ! =m] /ate 9 two or ?ree days4 ,at ,gauhati1 = in/ance1 ! riv]-gauge %[$ t1 at ab\t ?ree-qu>t]s ( an h\r aft] ! e>?quake1 ! wat] /ood #g feet #g in*es high] ?an on ! morn+ ( ,june #ab?2 at #g ,a4,m4 on ,june #ac? x _h fall5 to #e feet #h in*es1 & at ! same "t on ! two foll[+ days to #b feet #g in*es & #f in*es1 %[+ t ! wat] _h return$ ne>ly to its orig9al level aft] ! lapse ( two & a half days4 ,9 mo/ ( ! l>ge riv]s1 ! rise ( wat] 0 due to ! =mation ( p>tial dams =m$ by ! local elevation ( ! riv]-b$s describ$ above4 ,z ! b>ri]s 7 compos$ ( loose s&1 !y 7 gradually sc\r$ away & ! mat]ial 0 spread ov] ! bottom s z to leave ! wat] at a level slightly high] ?an t :i* x ma9ta9$ be=e ! e>?quake4 ,,l&slips4 ,! di/ribution ( l&slips %[s t _! =mation dep5ds almo/ z mu* on local conditions z on ! viol5ce ( ! %ock4 ,! effect ( ! latt] is manife/$ by _! limitation to a c]ta9 c5tral area4 ,to ! ea/ ( ! ,nor? ,ca*> hills1 few1 if any1 7 to be se52 b1 z f> z ,kohima1 cracks or incipi5t l&slips 7 =m$ on ! hillsides4 ,! ,sylhet valley & a l9e to ! we/ ( ,d>jil+ =m ! s\!rn & we/]n b\nd>ies ( ! l&slip area1 :i* 0 !re=e n less ?an #cjj miles 9 l5g? f ea/ to we/4 ,)9 ?is area1 h[ev]1 local conditions ass]t$ _! sup]iority4 ,among ! m important may be m5tion$ ! con/itution ( ! hills & ! pres5ce ( a ?ick sup]ficial lay] ( subsoil or rock ) an inn] b\nd+ surface ( weak cohesion1 ! slope ( ! hillsides1 & _! height f base to cre/4 ,?us1 ?\gh ! epic5tral area 0 situat$ *iefly to ! s\? ( ! ,brahmaputra valley 7,fig4 #ge71 ! ea/ & we/ range ( ! l&slips 0 m ext5sive 9 ! ,himalayas on ! nor? side ?an 9 ! ,g>o & ,khasi hills on ! s\?4 ,9 _m places1 ! /eep sides ( ! ,himalayan valleys exi/ always 9 a critical condition ( repose1 & ! effect ( ! ,indian e>?quake 0 su* t all along ! nor? side ( ! ,brahmaputra valley1 ! range is sc>r$ by l&slips1 ev5 to ! ea/ ( ,tezpur4 ,aga91 along ! s\!rn edge ( ! ,g>o & ,khasi hills1 l&slips 7 unusually preval5t4 ,view$ f ! deck ( a /eam] sail+ up to ,sylhet1 says ,mr4 ,oldham1 ! s\!rn face ( ^! hills pres5t$ a /rik+ sc5e4 ,! high s&/one hills fac+ ! pla9s ( we/]n ,sylhet1 usually =e/-clad f cre/ to foot1 7 /ripp$ b>e1 & ! :ite s&/one %one cle> 9 ! sun1 9 an app>5tly unbrok5 /ret* ( ab\t #bj miles 9 l5g? f ea/ to we/4 ,at ,*]rapunji1 also1 ! deep valleys 7 s scor$ t1 f a di/ance1 !re appe>$ to be m l&slip ?an unt\*$ hillside4 ,b 9 no "p1 probably1 7 l&slips m /rik+ly develop$ ?an 9 ! small valley ( ! ,mahdeo1 :i* =ms an amphi!atre ab\t f\r miles long f ea/ to we/1 & a mile & a half across1 ly+ to ! s\? ( ! ,blpakrm & ,pund5gru hills4 ,"h1 rem>ks ,mr4 ,oldham1 ev]y?+ comb9$ to fav\r ! =mation ( l&slips4 ,! hills 7 compos$ ( s(t s&/one1 !y 7 /eep-sid$1 high1 & n>r[ f side to side1 & consequ5tly 7 d\btless ?r[n into actual oscillation z a :ole2 :ile ! range ( motion ( ! wave p>ticle 0 n less ?an eight in*es ne> ! edge ( ! precipices4 ,! result 444 has be5 to produce an indescribable sc5e ( desolation4 ,ev]y:]e ! hillsides fac+ ! valley h be5 /ripp$ b>e f cre/ to base1 & ! seams ( coal & p>t+s ( %ale c\ld be se5 runn+ 9 & out ( ! irregul>ities ( ! cliffs ) a %>pness & di/9ctness :i* recall$ ! pictures ( ! caons ( ,colorado4 ,at ! bottom ( ! valley 0 a pil$-up heap ( dbris & brok5 trees1 :ile ! old /ream _h be5 oblit]at$ & ! /ream c\ld be se5 fl[+ ov] a s&y b$1 :i* mu/ h be5 rais$ _m feet above ! level ( ! old wat]c\rse4 ,9 ! s&/one di/ricts ( ! area "h consid]$1 ! l&slips _h "s important second>y effects4 ,along ! s\!rn edge ( ! ,g>o & ,khasi hills1 great s&-fans spread ov] ! fields1 & ! exposure ( ! hillsides =m]ly protect$ by =e/ left free scope = future d5udation4 ,e /ream ( any size has 9 ?is way deva/at$ _m squ>e miles ( c\ntry4 ,among ! hills !mselves1 m s& 0 br\ght d[n ?an ! /reams c\ld c>ry away1 & ev]y:]e _! b$s 7 rais$4 ,ord9>ily1 ! b$s ( ^! riv]s1 :i* are rag+ torr5ts :5 9 flood1 consi/ ( a succession ( deep pools sep>at$ by rocky rapids4 ,aft] ! ra9s ( #ahig1 x 0 f\nd t ! pools _h be5 fill$ up1 & ! rapids oblit]at$ by a great deposit ( s&1 ov] :i* ! riv]s fl[$ 9 a broad & %all[ /ream4 ,a few valleys 7 = a %ort "t b>r$ across by l&slips4 ,9 "o1 on ! nor!rn foot ( ! ,g>o hills1 a l&slip cross$ ! dra9age *annel & =m$ a %all[ pond1 :i* 0 n fill$ up by s& until ! end ( ,janu>y #ahih4 ,ne> ,s9ya1 9 ! nor!rn ,khasi hills1 an unusually l>ge l&slip =m$ a b>ri]1 ( :i* ! rema9s are m ?an #bjj feet above ! level ( ! riv]-b$4 ,beh9d ?is1 ! wat] accumulat$ 9 a great lake until ! beg9n+ ( ,septemb] #ahig1 :5 ! b>ri] bur/ & a flood ( wat] ru%$ d[n ! valley4 ,,rotation ,,( ,,pill>s1 ,,etc4 ,a curi\s effect ( e>?quakes /rong en\gh to damage build+s is t pill>s1 monum5ts1 etc41 may be fractur$ & ! upp] "p rotat$ ov] ! l[] )\t be+ ov]?r[n4 ,ev5 9 ,h]e=d & ! surr\nd+ villages1 sev]al p9nacles & *imney-/acks 7 twi/$ by ! e>?quake ( #ahif4 ,! int]e/ ( ! ph5om5on1 :i* has be5 kn[n1 s9ce #agee1gd is ma9ly hi/orical1 = ! endeav\r to discov] its cause 0 ! orig9 ( ,mallet's views on ! dynamics ( e>?quakes4 ,p>tly1 also1 x lies 9 ! difficulty ( f9d+ a satisfactory explanation1 or r 9 decid+ :i* ( ?ree or f\r possible explanations is ! true "o 9 any p>ticul> case4 ,illu/ration3 ,,fig4 #gd4--,twi/+ ( monum5t at ,*hatak4 7,oldham47 ,! ,indian e>?quake (f]$ exceptional opportunities = /udy+ ! ph5om5on 9 ! l>ge numb] ( examples obs]v$ & ! v>iety ( objects rotat$4 ,none c\ld be m /rik+ ?an ! twi/$ monum5t to ,george ,+lis1 repres5t$ 9 outl9e 9 ,fig4 #gd4 ,*hatak1 :]e ?is is situat$1 lies close to ! s\!rn b\nd>y ( ! epic5tral area4 ,! monum5t is an obelisk1 built ( broad flat bricks or tiles on a base ( #ab feet squ>e1 & orig9ally m ?an #fj feet high4 ,x 0 split by ! e>?quake into f\r portions4 ,! two upp]1 ab\t six & n9e feet long1 7 ?r[n d[n2 :ile ! ?ird1 #bb feet high1 rema9s /&+1 b is twi/$ ?r\gh an angle ( #cj ) respect to ! l[e/ "p1 :i* is unmov$4 ,! upp] ( ^! two p>ts _h evid5tly rock$ on ! l[]1 z ! corn]s & edges 7 spl9t]$1 & bel[ ! fracture a slice ( masonry ab\t #ae in*es ?ick1 :i* 0 n bond$ into ! ma9 mass1 0 split (f by ! pressure on its upp] end4 ,! plan ( ! p>ts /ill /&+ is %[n 9 ! l[] "p ( ,fig4 #gd4 ,! possible explanations ( ! ph5om5on are at lea/ ?ree 9 numb]4 ,accord+ to ! fir/1 :i* 0 giv5 by ,mallet 9 #ahdf1 ! adhesion ( ! twi/$ portion to its base is n uni=m1 & ! resultant resi/ance to motion is n 9 ! same v]tical plane z ! wave-movem5t4#ge ,"s ye>s lat]1 ,mallet (f]$ ano!r explanation4 ,! body1 he imag9$1 might be tilt$ on "o edge by ! e>?quake1 &1 :ile /ill rock+1 a second %ock oblique to ! fir/ might twi/ x ab\t t edge4#gf ,9 #ahhj1 ,pr(essor ,t4 ,gray sugge/$ t ! column might be tilt$ on "o corn] & !n twi/$ r\nd x by lat] vibrations ( ! same %ock4#gg ,none ( ^! !ories1 ,mr4 ,oldham argues1 c give by itself a complete explanation ( ! ph5om5a obs]v$ 9 ! c5tral di/rict ( ! ,indian e>?quake2 & he !re=e fav\rs an ext5sion ( ! second !ory1 :i*1 ?\gh fir/ propos$ 9 #ahhb1gh 0 ?\ght out indep5d5tly & 9 great] detail by himself4 ,:5 ! focus is ( consid]able dim5sions1 ! %ock at neighb\r+ places is con/antly v>y+ 9 direction1 ow+ to ! arrival ( vibrations f diff]5t p>ts ( ! focus4 ,?us1 in/ead ( ! two sep>ate %ocks requir$ by ,mallet's second explanation1 we h a numb] ( closely successive impulses frequ5tly *ang+ 9 direction & giv+ rise to :at is kn[n 9 ! ,s\? ( ,europe z a vorticose %ock4 ,&1 in/ead ( a s+le twi/ ( ! pill>s ab\t "o c5tre only1 we h a s]ies ( small twi/s r\nd a numb] ( diff]5t c5tres1 accompani$ 9 consequ5ce by a mu* small] displacem5t ( ! c5tre ( gravity ?an w\ld h occurr$ _h ! same rotation be5 accompli%$ 9 "o op]ation4 ,! !ory1 x w be se51 acc\nts = ! twi/+ ( ! pill> )\t ov]?r[1 & = ! spl9t]+ ( ! edges dur+ ! rock+ ( ! column4 ,x expla9s :y 9 any di/rict a numb] ( simil>ly plac$ objects are g5]ally twi/$ 9 ! same direction4 ,moreov]1 a l[ column rocks to & fro m rapidly ?an a tall "o simil> 9 =m & position1 s t1 at ! in/ant :5 a lat] impulse comes f a diff]5t direction1 two su* columns might happ5 to be tilt$ on opposite edges1 & w\ld !n be twi/$ 9 opposite directions4 ,9 c]ta9 cases1 !n1 z occurr$ at sev]al places dur+ ! ,indian e>?quake1 an object may rotate 9 "o direction1 :ile o!rs1 simil> 9 e respect b size1 may be twi/$ 9 ! opposite direction4 ,,aft]-,,%ocks4 ,frequ5cy ( ,aft]-,%ocks4--,= "s days aft] ! great e>?quake1 ! aft]-%ocks by _! v frequ5cy & by _! wide di/ribution baffl$ close inquiry4 ,dur+ ! fir/ #bd h\rs1 hundr$s 7 felt at all po9ts ( ! epic5tral area2 inde$1 x is n too mu* to say t = sev]al days ! gr\nd 0 nev] actually at re/4 ,at ! ,bordw> tea-e/ate1 :i* is trav]s$ by "o ( ! great fractures to be describ$ 9 ! next section1 ! surface ( a glass ( wat] on a table 0 = a :ole week 9 a con/ant /ate ( tremor2 & at ,tura a hang+ lamp 0 kept cont9ually sw++ = ! fir/ ?ree or f\r days4 ,mo/ ( ^! %ocks 71 ( c\rse1 v slight2 b1 int]sp]s$ among !m1 7 o!rs ( great] /r5g?1 & a few ( consid]able viol5ce4 ,"o1 on ,june #ac?1 ab\t eight h\rs aft] ! e>?quake1 0 s5sible beyond ,allahabad--t is1 = m ?an #ebj miles f ! epic5tre2 & ano!r on ! same day 0 felt 9 ,calcutta1 di/ant #bee miles4 ,on ,june #ad?1 #bbnd1 & #bi?1 & aga9 on ,augu/ #bnd & ,octob] #i?1 %ocks 7 notic$ 9 t city2 b1 aft] ! latt] date1 ! di/urb$ area ( no %ock rea*$ to s great a di/ance4 ,to =m any e/imate ( ! total numb] ( aft]-%ocks is impossible1 ev5 = any "o /ation4 ,at fir/1 li/s 7 kept at isolat$ places1 su* z ,%illong1 ,maimans+h1 ,dhubri1 & a few o!rs4 ,!n1 f ,july #ae?1 ?r\gh ,mr4 ,oldham's ef=ts1 ! records became m num]\s until ! end ( ! ye>1 aft] :i* int]e/ 9 ! subject decl9$4 ,mr4 ,oldham's catalogue closes ) ! ye> #ahih2 b ! regi/] ( a r\ghly-con/ruct$ seismograph1 erect$ at ,%illong 9 ,july #ahig1 cont9ues to ! pres5t day4 ,imp]fect z all non-in/rum5tal regi/]s mu/ be1 !y nev]!less furni% "s idea ( ! frequ5cy ( ! aft]-%ocks4 ,?us1 until ! end ( ,june1 #fgi %ocks 7 record$ at ,rangmahal 7,nor? ,gauhati71 #ace at ,maimans+h1 #hi at ,ku* ,bih>1 & #hc at ,kaunia 7omitt+ ^? on ,june #ab?74 ,aga91 f ,augu/ #a/ to #ae?1 #ahb 7 felt at ,goalp>a1 #aea at ,d>angiri1 #abd at ,tura1 #aje at ,bijni1 #id at ,lakhipur1 #id at ,kri%nai1 #dh at ,dhubri1 #bh at ,rangpur1 & #ab at ,ku* ,bih>2 :ile at ,borpeta1 #aac %ocks 7 report$ dur+ ! fir/ n9e days ( ,augu/4 ,turn+ to ! regi/]s ( long] duration1 we f9d t at ,maophlang 7ne> ,%illong7 #a1aid %ocks 7 felt by "o obs]v] f ,septemb] #ab?1 #ahig1 to ,octob] #g?1 #ahih2 at ! neighb\r+ /ation ( ,mairang1 #a1jfe f ,septemb] #g?1 #ahig1 to ,decemb] #ca/1 #ahih2 & at ,tura1 9 ! ,g>o hills1 #a1ade %ocks f ,july #ba/1 #ahig1 to ,decemb] #ca/1 #ahih4 ,! total numb] ( e>?quakes regi/]$ by ! seismograph at ,%illong f ,augu/ #ahig to ! end ( #aija am\nts to #a1bgd1 & all ( ^! 7 probably /rong en\gh to ar\se ! obs]v] f sleep4 ,outside ! epic5tral area1 ,mr4 ,oldham's li/ includes #hh %ocks f ,june #ab? to ,july #ae?1 ab\t #iej f ,july #af? to ,decemb] #ca/ 7! p]iod :5 ! aft]-%ocks 7 mo/ c>efully obs]v$71 & #bif %ocks dur+ ! ye> #ahih4 ,geographical ,di/ribution ( ,aft]-,%ocks4--,:5 we endeav\r to comp>e ! li/s ( aft]-%ocks at diff]5t places1 we are at once met by two s]i\s difficulties1--! imp]fection ( ! records & ! approximate "* ( ! times ( occurr5ce4 ,mak+ e all[ance1 h[ev]1 = ^! defici5cies1 x is evid5t t v few ( ! %ocks felt at any "o /ation 7 p]ceptible at its neighb\rs2 9 o!r words1 t ! %ocks orig9at$ 9 a l>ge numb] ( foci scatt]$ ov] a v wide area4 ,= in/ance1 two ( ! mo/ c>efully kept regi/]s ( aft]-%ocks are ^? compil$ at ,maophlang 7ne> ,%illong71 & at ,mairang1 only #aa miles to ! nor?-we/4 ,n[1 betwe5 ,septemb] #ab? & ,septemb] #bh?1 #ahig 7bo? dates inclusive71 #ib %ocks 7 felt at ,maophlang & #hc at ,mairang4 ,( ! =m]1 #cg 7 describ$ z sm>t1 #de slight1 & #aj feeble2 ( ! latt]1 #f z sm>t1 #i slight1 #fe feeble1 & #c v feeble4 ,b1 ( ! total numb]1 only #bj 7 felt at bo? places at record$ times t 7 n m ?an fifte5 m9utes ap>t2 #ac be+ describ$ z sm>t--"o at bo? places1 "o at ,mairang alone1 & ! rema9+ #aa at ,maophlang alone4 ,:5 %ocks occur s frequ5tly1 z 9 ^! cases1 x is inevitable t1 ev5 if all 7 indep5d5t1 "s %\ld co9cide approximately 9 "t ( occurr5ce4 ,x is !re=e probable t only "o 9 e eight %ocks1 & possibly only "o 9 e twelve1 0 felt at bo? places4 ,! actual numb]s ( %ocks felt )9 /at$ p]iods at diff]5t places are p]haps h>dly comp>able1 ow+ to ! obvi\s imp]fection ( ! records & ! probably v>y+ /&>ds adopt$ by ! report]s4 ,b !re c be little d\bt t c]ta9 di/ricts 7 m subject to aft]-%ocks ?an o!rs1 especially su* places z ,nor? ,guahati1 ,%illong1 & neighb\r+ villages1 ,tura1 ,d>angiri1 ,goalp>a1 ,bijni1 ,borpeta1 ,kaunia1 & ,rangpur4 ,on ! o!r h&1 !y seem to h be5 unusually sc>ce at ,dhubri & 9 ! di/rict to ! nor?-we/1 & !y became r>e at ,gauhati long be=e !y ceas$ to be frequ5t at ,borpeta4 ,9 ! pla9 to ! s\? ( ! ,g>o & ,khasi hills1 !y 7 also uncommon1 ! comb9$ records = ,sylhet & ,sonamganj = ,augu/ #a-ae giv+ only #bj %ocks1 &1 nei!r to ! ea/ nor to ! we/ ( ^! places1 is !re any sign ( great] frequ5cy4 ,s\nd-,ph5om5a ( ,aft]-,%ocks4--,_m ( ! aft]-%ocks 7 accompani$ by s\nd1 or else consi/$ ( s\nd-vibrations only2 & ,mr4 ,oldham notices t su* s\nds 7 equally frequ5t bo? on ! rocky gr\nd ( ! hills & on alluvial pla9s ne>ly all ! %ocks t orig9at$ "u ! ,borpeta pla9 be+ att5d$ by di/9ctly audible rumbl+s4 ,dur+ 8 t\r 9 ! epic5tral area 9 ! w9t] ( #ahig-ih1 ,mr4 ,oldham _h _m opportunities = obs]v+ ^! e>?-s\nds4 ,!y 71 he says1 close to ! l[] limit ( audibility1 less a note ?an a rumble1 & v l di/ant ?und]1 ?\gh sometimes !y consi/$ ( a rapid succession ( %ort s\nds1 su* z is caus$ by a c>t :5 driv5 rapidly ov] a r\gh pavem5t4 ,z a rule1 !y began z a l[1 almo/ inaudible rumble1 gradually increas+ 9 l\dness1 ?\gh to a v v>y+ degree1 & !n gradually dy+ out aft] hav+ la/$ any?+ f #e to #ej seconds4 ,x _c be said t !re 0 any connection betwe5 ! duration & ! l\dness ( ! s\nds1 "s ( ! mo/ prolong$ nev] becom+ l\d1 & "s ( ^? :i* la/$ a %ort] p]iod be+ z l\d z ord9>y ?und] at a di/ance ( two or ?ree miles4 ,mr4 ,oldham records an int]e/+ fact 9 connection ) ! di/ribution ( ! e>?-s\nds4 ,at ,naphak1 9 ! ,g>o hills & ab\t five miles s\? ( ,sam91 #dh di/9ct rumbles 7 he>d dur+ #bc h\rs on ,janu>y #ba-bc1 #ahih1 only sev5 ( !m be+ accompani$ by a p]ceptible %ock4 ,at ,sam91 :i* 0 visit$ next1 !y 7 mu* less frequ5t1 n m ?an #h or #aj a day1 & mo/ ( !m att5d$ by tremors4 ,at ,damra1 a few miles to ! nor?-ea/1 !y aga9 became frequ5t2 :ile1 9 ! ,*$rang valley1 v few 7 he>d1 & only a small proportion ( !m 7 unaccompani$ by s5sible %ocks4 ,9 ! next section1 x w be se5 t ! mo/ conspicu\s fault-sc>ps kn[n 9 ! epic5tral area pass close by ,sam9 & along ! ,*$rang valley4 ,?us1 ?\gh ! /atem5t p]haps requires fur!r confirmation1 x w\ld appe> t e>?-s\nds 7 m common :]e ! surface ( ! gr\nd _h be5 m]ely b5t ?an :]e fractures ext5d$ "r up to ! surface4 ,,/ructural ,,*anges ,,9 ,,! ,,epic5tral ,,area4 ,we come n[ to ! important features :i* assign ! ,indian e>?quake to a small class ap>t f ne>ly e o!r %ock4 ,mo/ e>?quakes are due to movem5ts t are entirely deep-seat$4 ,if /rong en\gh1 !y may precipitate l&slips or fissure ! alluvial soil ne> riv]-*annels4 ,9 ! ,neapolitan1 ,&alusian1 & ,*>le/on e>?quakes1 !re 7 _m su* effects ( ! %ock )9 ! meizoseismal areas4 ,9 all ?ree1 h[ev]1 ! di/urbances produc$ 7 sup]ficial2 no /ructural *ange1 no fissur+ t did n die out rapidly d[nw>ds1 0 9 any place p]ceptible4 ,9 ! ,rivi]a e>?quake1 ! seismic sea-waves po9t to a small displacem5t ( ! ocean-b$2 b x is only 9 ! long fault-sc>p ( ! c5tral ,japanese pla9 t we f9d a rival ( ! m\nta9-mak+ movem5ts t gave rise to ! ,indian e>?quake4 ,! b\nd>y ( ! epic5tral area1 to ! gr[? ( :i* ^! di/ortions contribut$1 is repres5t$ by ! curve m>k$ ,a 9 ,fig4 #fh1 & on a l>g] scale by ! cont9u\s l9e ,a 9 ,fig4 #ge4 ,a great "p ( ! di/rict is occupi$ by a gr\p ( hills kn[n by v>i\s names locally1 b :i* are conv5i5tly includ$ "u ! g5]al t]m ( ! ,assam range4 ,to avoid ! confusion ( hill-%ad+1 only ! b\nd>y ( ! range is indicat$ 7by ! brok5 l9e7 9 ! map 9 ,fig4 #ge4 ,! ,g>o hills =m ! we/]n "p1 & ! ,khasi & ,ja9tia hills ! c5tral & we/]n p>ts1 ( ! range z !re depict$4 ,!y are =m$ *iefly ( cry/all9e gneissic & granitic rocks & "s metamorphic s*i/s & qu>zite1 ) cretace\s & t]ti>y rocks ( v>y+ ?ickness along its s\!rn edge4 ,?ree /ages h be5 di/+ui%$ 9 ! hi/ory ( ! range4 ,dur+ ! e>lie/1 an old l&-surface 0 worn d[n by ra9 & riv]s till !y 7 almo/ incapable ( produc+ any fur!r *ange4 ,traces ( ?is surface are /ill visible 9 ! plateau "* ( ! mass4 ,x 0 !n elevat$1 n uni=mly1 b along a s]ies ( faults1 s t x n[ consi/s ( a succession ( ranges1 ! face ( ea* range be+ a fault-sc>p1 & its cre/ ! edge ( an adjo9+ plateau slop+ away f ! summit4 ,) ?is elevation began ! ?ird & la/ /age4 ,! /reams 7 able to "w aga91 & deep gorges 7 cut out ( ! range1 s t 9 p>ts its orig9al "* 0 ne>ly effac$4 ,b ! ret5tion ( t "* 9 o!r di/ricts is ( c\rse evid5ce ( ! comp>atively rec5t date ( ! f9al elevation4 ,illu/ration3 ,,fig4 #ge4--;,epic5tral ,area ( ,indian ,e>?quake4 7,oldham47 ,ow+ to ! great size ( ! epic5tre & to ! ?ickness ( ! =e/s :i* cov] s mu* ( its area1 a comp>atively small "p ( x c\ld be trav]s$ by ,mr4 ,oldham dur+ 8 t\r 9 ! w9t] ( #ahig-ih4 ,! positions ( ! m important /ructural *anges are indicat$ 9 ,fig4 #ge4 ,( ^!1 ! fault-sc>ps are repres5t$ by cont9u\s /raight l9es1 ! ,bordw> fracture by ! dott$ /raight l9e1 pools & lakes n due to fault+ by black ovals1 report$ *anges 9 ! aspects ( ! hills by circles1 & ! pr9cipal /ations ( ! revis$ trigonometrical survey by crosses4 ,fault-,sc>ps4--,! mo/ important fault-sc>p is t call$ by ,mr4 ,oldham ! ,*$rang fault1 aft] ! /ream :i* co9cides r\ghly ) a great "p ( its c\rse4 ,! long] /raight l9e 9 ,fig4 #ge repres5ts its position & g5]al direction1 & ! sket*-map 9 ,fig4 #gf gives ! plan ( its s\!rn half4 ,f ^!1 x w be se5 t ! fault foll[s on ! :ole a ne>ly /raight pa? f s\?-s\?-ea/ to nor?-nor?-we/ = n less ?an twelve miles1 & t its ?r[1 z indicat$ by ! numb]s to ! "r 9 ,fig4 #gf2 is v v>iable1 be+ z]o 9 "s places1 & 9 "o z mu* z #ce feet or m4 ,! up?r[ is uni=mly on ! ea/]n side ( ! fault4 ,at its s\!rn end1 z mapp$ 9 ,fig4 #gf1 !re is no p]ceptible ?r[ at ! surface1 b v>i\s m>ks ( viol5ce are manife/$ 9 ! fissur+ ( ! hillside & ! snapp+ ( small trees4 ,ab\t a qu>t] ( a mile f ?is po9t1 ! fault crosses a tribut>y /ream1 :]e ! ?r[ am\nts to two feet1 & ! same di/ance f>!r on x meets ! ,*$rang riv]1 ! b$ ( :i* x crosses _m times 9 its %ort c\rse4 ,illu/ration3 ,,fig4 #gf4--,plan ( ,*$rang fault4 7,oldham47 ,mr4 ,oldham describes ! fault 9 detail1 z obs]v$ by him 9 ,febru>y #ahih4 ,"h1 x w be suffici5t to ref] to its m important features1 & to its effects on ! sup]ficial dra9age ( ! di/rict4 ,at ! spot m>k$ a 7,fig4 #gf7 ! riv]1 aft] runn+ on ! we/ or d[n-?r[ side ( ! fault = ne>ly half a mile1 meets ! sc>p1 & is pond$ back by x = ab\t a qu>t] ( a mile up/ream4 ,= ! next half-mile1 ! riv] keeps to ! up?r[ side ( ! fault1 ! sc>p ( :i* blocks ! tribut>y /reams f ! we/1 =m+ a numb] ( small pools4 ,at ! la/ ( ^!1 ! total ?r[ is n less ?an #be feet4 ,a little f>!r on1 ! fault crosses ! ,*$rang & causes ! wat]fall at b1 ! height ( :i*1 ow+ to ! fall ( dislodg$ fragm5ts1 does n exce$ n9e feet4 ,! fault !n runs along ! old & n[ dry b$ ( ! riv]1 :ile ! /ream itself fl[s 9 a depression on ! d[n-?r[ side4 ,ab\t a qu>t] ( a mile bel[ ! wat]fall1 ! fault crosses ! riv]1 & soon aft] ent]s a l>ge %eet ( wat] at c1 half a mile long1 f #cjj to #djj y>ds wide1 & ) a maximum dep? ( #ah feet4 ,at fir/1 ! pool spreads on bo? sides ( ! fault1 b ! inequalities due to ! sc>p are evid5c$ by s\nd+s4 ,at ! po9t :]e ! fault leaves ! pool1 its ?r[ is r$uc$ to no?+1 & x is j "h t ! wat] atta9s its greate/ dep?4 ,to ! nor? ! ?r[ increases r rapidly1 to #be feet 9 a qu>t] ( a mile4 ,b ! peculi>ity ( ?is pool is t x is n1 l ! o!rs m5tion$ above1 damm$ back by ! fault-sc>p4 ,!re is no b>ri] at its nor!rn end1 :]e ! riv] escapes1 except t =m$ by ! gradually increas+ ?r[ ( ! fault4 ,! pool is simply due to ! rev]sal ( ! natural slope ( ! riv]-b$1 caus$ by ! =mation ( a roll or undulation 9 ! gr\nd on ! up?r[ side ( ! fault4 ,its rec5t orig9 is evid5t f ! numb] ( dead trees & bamboo clumps /ill /&+ 9 ! wat]4 ,= a mile aft] ! fault leaves ! pool1 its ?r[ v>ies consid]ably4 ,x rises1 z already m5tion$1 f z]o to #be feet4 ,a little f>!r on1 ! fault runs up ! side ( a spur1 ! ?r[ increas+ to #ca feet2 &1 9 ?is "p1 ! viol5ce ( ! %ock 0 %[n by ! dislodgm5t ( blocks ( granite z mu* z #bj feet 9 diamet]1 & by ! ov]?r[ or de/ruction ( _m trees4 ,aft] cross+ ! spur1 ! fault returns to ! neighb\rhood ( ! riv]1 & crosses its b$ f\r times1 =m+ pools 7e1 g7 or wat]falls 7d1 f7 accord+ z ! sc>p occurs on ! d[n/ream or up/ream side4 ,! ?r[ ( ! fault !n *anges consid]ably )9 little m ?an half a mile1 f #ah feet to z]o & aga9 to #bj feet1 ! undulation s =m$ produc+ a l>ge pool 7h7 entirely on ! up?r[ side ( ! fault4 ,at ! po9t m>k$ i on ! map1 ! riv] once m crosses ! fault2 b ! bottom ( ! valley is fill$ ) alluvium1 &1 in/ead ( a wat]fall1 a l>ge s&y delta spreads d[n ! /ream4 ,! sc>p is1 h[ev]1 readily trac$ on ! ea/ side ( ! riv]1 a ?r[ ( #cb feet be+ measur$4 ,aft] ?is1 ! alluvium becomes ( consid]able ?ickness1 & ! cont9uation ( ! fault is m>k$ by a %ort slope1 :i* tilts ov] ! trees :5 x trav]ses =e/-l&4 ,leav+ ! valley ( ! ,*$rang1 ! fault crosses an op5 pla91 & is foll[$ ) "s difficulty to ! neighb\rhood ( ,jhira1 :]e1 ow+ to ! ?ick b$ ( alluvium1 x =ms a g5tle roll or undulation ( ! surface1 cross+ ! ma9 *annel ( ! ,kri%nai to ! nor?-ea/ ( ,jhira4 ,on ! we/ side ( ?is b>ri] a l>ge %eet ( wat]1 a mile & a half 9 l5g?1 ?ree-qu>t]s ( a mile wide1 & #ab feet 9 dep?1 ga!r$ ov] ! village ( ,jhira4 ,on ! ea/ side ( ! ,jhira lake1 says ,mr4 ,oldham1 !re is ample evid5ce ( *ange ( level1 = "p ( ! dry l& 0 =m]ly 444 p]petually "u wat]1 & at "o place ! rema9s ( an old irrigation *annel c be se54444 ,at ! nor!rn end ( ! lake ! dra9age n[ makes its escape 9 a broad & %all[ %eet ( wat] ov] :at 0 once high l& cov]$ ) sal =e/4 ,?is is ! la/ m>k$ feature due to ! ,*$rang fault4 ,beyond ! nor? ( ,jhira ! ?r[ rapidly dim9i%es1 & p]haps dies out altoge!r be=e rea*+ ! l[ hills ly+ to ! nor? ( t village4 ,9 sev]al ways1 ?is fault-sc>p diff]s f t =m$ ) ! ,japanese e>?quake ( #ahia4 ,?r\gh\t its c\rse ! d[n-?r[1 :]ev] x is p]ceptible1 is inv>iably to ! we/2 9 no place c\ld any trace ( horizontal %ift+ be detect$2 & ! plane ( ! fault1 :5 x trav]s$ rock1 is practically v]tical4 ,:e!r ! sc>p 0 =m$ by ! elevation ( ! rock to ! ea/ ( ! fault1 or by ! depression ( t to ! we/1 or by bo? su* movem5ts at once1 !re is no decisive evid5ce2 b !re are v good reasons = believ+ ! fir/ alt]native to be ! true "o4 ,! undulations 9 ! gr\nd :i* gave rise to ! l>ge pools at c & h 7,fig4 #gf7 occur on ! ea/ side ( ! fault4 ,also1 betwe5 ! outlet ( ! lake at ,jhira & ! po9t :]e ! ,kri%nai rejo9s its orig9al *annel1 ! gradi5t ( ! riv] approa*es t ( a m\nta9 /ream1 al?\gh ! new b$ consi/s ( alluvium1 & n ( rock4 ,n[1 ! alluvial pla9 ( ?is di/rict is rais$ s slightly above ! sea-level t no subsid5ce great en\gh to h caus$ ! exi/+ gradi5t c\ld h occurr$ )\t ! depress$ area be+ flood$ ) wat]4 ,?\gh "s movem5ts may h tak5 place on ! we/ side ( ! fault1 x seems cle>1 !n1 t elevation ( ! rock on ! ea/ side 0 ! pr$om9ant1 if n ! sole1 cause ( ! fault-sc>p4 ,z ! ,*$rang fault has be5 describ$ some:at fully1 a brief ref]5ce to ! re/ w be suffici5t ,! only o!r kn[n sc>p ( any consequ5ce lies ab\t t5 miles to ! s\? ( ! ,*$rang fault1 & runs by ! village ( ,sam91 ) an av]age c\rse f ,e4 #cj ,s4 to ,w4 #cj ,n4 ,its total l5g? does n exce$ #b-a_/b miles4 ,! d[n-?r[ is uni=mly to ! nor?1 & ! ?r[1 :i* am\nts to t5 feet ne> its c5tre1 gradually dim9i%es to z]o at ei!r end4 ,sev]al pools are =m$ along ! c\rse ( ! fault-sc>p by ! block+ ( small /reams4 ,! ,bordw> ,fracture4--,9 ! map ( ! epic5tral area 7,fig4 #ge71 ?is rem>kable fracture is repres5t$ by a dott$ /raight l9e4 ,x is app>5tly an incipi5t fault4 ,?\gh traceable = a di/ance ( ab\t sev5 miles1 at no po9t is !re any decisive evid5ce ( ei!r v]tical or horizontal displacem5t2 &1 ev5 if "s d\btful indications ( a *ange ( level %\ld be real1 ! ?r[ mu/ c]ta9ly be less ?an "o foot4 ,yet1 9 ! imm$iate neighb\rhood ( ! fracture1 ! viol5ce ( ! %ock 0 extreme4 ,trees h be5 ov]?r[n or kill$ z !y /ood2 a huge mass ( rock1 dislodg$ f ne> ! cre/ ( ! hills1 has roll$ d[n ! slope1 scor+ ! side ( ! hill4 ,on ! opposite side an equally l>ge block has be5 dislodg$1 & 9 its d[nw>d c\rse cle>$ a /raight track d[n ! hill2 & on ! summit a gap has be5 cle>$ by ! ov]?r[ ( trees along ! l9e ( fracture4 ,be+ only a few in*es 9 wid? :]e x has r5t ! solid rock1 ! fracture 0 difficult to foll[ 9 _m p>ts ( its c\rse4 ,b1 ?r\gh =e/-clad l&1 its track 0 m>k$ by a well-def9$ b& ( ab\t half a mile broad1 9 :i* ov]turn$ trees are mu* m abundant ?an on ei!r side1 & t[>ds ! c5tre ( ?is b& ! ov]turn$ trees are n only m num]\s1 b _m ( ! small] ones1 up to six in*es 9 diamet]1 h be5 snapp$ across by ! viol5ce ( ! %ock4 ,lakes & ,pools n due to ,fault+4--,a few miles to ! s\? ( ! ,*$rang & ,sam9 faults1 & also ( ! ,bordw> fracture1 occurs a gr\p ( lakes or pools1 repres5t$ on ! map ( ! epic5tral area 7,fig4 #ge7 by small black ovals4 ,9 ! gradual increase 9 dep? f ei!r end1 !y resemble ! two l>ge %eets ( wat] along ! c\rse ( ! ,*$rang fault 7c & h1 ,fig4 #gf71 b !y diff] f !m 9 hav+ no direct connection ) any app>5t fault4 ,"o ( ^! pools lies 9 ! valley ( ! ,rong?am riv]1 to ! s\? ( ! ,sam9 fault4 ,x seem$1 at fir/ sight1 to be no?+ m ?an an ord9>y pool1 su* z may be se5 on any m\nta9 /ream4 ,on ! bottom1 & close to ! outlet1 h[ev]1 are co>se1 p>tially r\nd$ b\ld]s1 exactly resembl+ ^? f>!r d[n ! riv]2 &1 z ! old b$ 0 foll[$ up1 ^! became coat$ ) a slight deposit ( s& & mud1 po9t+ cle>ly to a *ange 9 ! conditions "u :i* !y 7 =m$4 ,! wat] gradually deep5$1 until trees 7 met /&+ 9 ! wat]1 b kill$ by ! rec5t subm]g5ce ( _! roots4 ,! pool is ne>ly a qu>t] ( a mile long1 & its greate/ dep? 7#ab feet7 occurs ne> ! middle1 j :]e ! =m] /ream1 ) an av]age dep? ( ab\t a foot1 0 cross$ by ! track f ,d>angiri4 ,t[>ds ! upp] end1 ! wat] %all[s z gradually z x deep5s at ! o!r1 & ends 9 a delta ( b\ld]s br\ght d[n by ! /ream above4 ,z no fault c\ld be discov]$ 9 ! neighb\rhood ( ! pool1 x is evid5t t its =mation 0 due to a b5d ( ! riv]-b$1 ! maximum *ange ( level1 tak+ into acc\nt ! riv]-slope1 be+ n less ?an #bd feet4 ,simil> features *>act]ise ! o!r pools t 7 exam9$1 "s ( :i* are small]1 & o!rs l>g]1 ?an t describ$ above4 ,"o1 high] up ! valley ( ! ,rong?am1 has a l5g? ( ab\t #a-a_/b mile & a maximum dep? ( #ah feet4 ,o!rs ( ! same type1 b ( small] size1 7 obs]v$ among ! ,khasi hills1 ab\t fifte5 miles s\? ( ! ,bordw> fissure2 & x is probable t _m o!rs w\ld h be5 f\nd 9 ! int]m$iate di/rict1 :i* ,mr4 ,oldham 0 unable to visit4 ,*anges 9 ! ,aspects ( ! ,hills4--,!re are1 aga91 o!r facts ( consid]able int]e/ :i* po9t to *anges ( level ov] a wide area2 ! places :]e !y 7 notic$ be+ indicat$ by small circles 9 ,fig4 #ge4 ,= in/ance1 f ,maophlang1 ne> ,%illong1 a road leads to ! neighb\r+ /ation ( ,mairang4 ,be=e ! e>?quake1 only a %ort /ret* ( ?is road c\ld be se5 f ! =m] place1 z x r\nd$ a spur ab\t ?ree miles away4 ,n[1 a mu* long] /ret* is visible1 & x c also be se5 pass+ r\nd ! next1 & previ\sly hidd51 spur4 ,9 ?is di/rict ! movem5ts seem to h cont9u$ ) ! aft]-%ocks2 =1 be=e ! e>?quake1 ! cre/ only ( a ridge ab\t a mile & a half to ! we/ 0 visible2 :ile1 aft] x1 a consid]able portion c\ld be se51 & mu* m "s mon?s lat] ?an imm$iately aft] ! %ock4 ,aga91 f a spot ne> ! s\!rn end ( ! ,*$rang fault1 x us$ to be only j possible to see ! ,brahmaputra ov] an int]v5+ hill2 :]eas1 n[1 ! :ole wid? ( ! riv] has come into view4 ,la/ly1 at ,tura1 :i* is #ie miles we/ ( ,maophlang1 a battalion ( milit>y police 7 accu/om$ to signal by heliograph ) ano!r /ation1 ,r[m>i1 #ae miles f>!r to ! we/4 ,?is1 =m]ly1 c\ld j be done by means ( a ray :i* graz$ a hill betwe5 ! two places2 x c n[ be done q easily1 &1 9 addition1 a broad /ret* ( ! pla9s ea/ ( ! ,brahmaputra is visible f ! same spot4 ,revision ( ! ,trigonometrical ,survey4--,! movem5ts describ$ 9 ! prec$+ pages are ( c\rse ref]r$ to po9ts :i* may !mselves h be5 displac$1 & only a revision ( ! trigonometrical survey ( ! epic5tral area & ( "p ( ! surr\nd+ di/rict c\ld det]m9e _! absolute magnitude4 ,dur+ ! cold wea!r ( #ahig-ih1 "s ( ! triangles 7 re-measur$ by a memb] ( ! trigonometrical survey2 b1 z ! "t at 8 disposal 0 %ort1 !y 7 conf9$ to ! ea/]n "p ( ! epic5tral area1 z ! focus at t "t 0 suppos$ to lie "u ! ,khasi hills4 ,! positions ( "s ( ^! /ations are indicat$ by crosses 9 ,fig4 #ge2 & 9 ,fig4 #gg ! m important triangles are %[n4 ,9 ! revis$ "w1 all t[] /ations1 consi/+ ( brick t[]s built on alluvium1 7 omitt$1 z x c\ld n be assum$ t !y _h be5 undi/urb$ by displacem5ts ( ! sup]ficial b$s4 ,9 re-calculat+ ! l5g?s ( ! sides1 ! side ,rangsanobo-,t>amun ,tila 0 adopt$ z ! initial base1 & ! height ( ,rangsanobo z ! initial height2 a *oice :i* lat] exp]i5ce %[$ to be un=tunate1 = ,t>amun ,tila probably lies j outside1 & ,rangsanobo )91 ! epic5tral area4 ,( ! #af sides1 ^: old & new l5g?s 7 comp>$1 only "o 0 f\nd to be app>5tly un*ang$1 two 7 %ort5$ by an in* or two1 :ile ! o!rs 7 all l5g!n$ by am\nts v>y+ f "o to eight or n9e feet1 ! numb]s affix$ to ! sides 9 ,fig4 #gg d5ot+ ! calculat$ increases 9 feet4 ,assum+ ! new base-l9e to be unalt]$ by ! e>?quake movem5ts1 ^! *anges imply ! foll[+ displacem5ts ( ! pr9cipal /ations3--,?anj9a? #f feet1 ,mun #d1 & ,laid]a #b1 feet to ! nor?2 ,mop5 #e1 ,d+hei #i1 ,l&au ,modo #ab1 & ,umt] #aa1 feet to ! nor?-we/2 & ,mos+i #c1 & ,mau!rrican #e1 feet to ! we/4 ,at ! same "t1 ! height ( mo/ ( ! /ations 0 f\nd to be increas$ ) ref]5ce to t ( ,rangsanobo3 ,mun by #b feet1 ,?anj9a? & ,umt] by #c1 ,mos+i by #d1 ,t>amun ,tila & ,laid]a by #f1 ,d+hei by #g1 ,l&au ,modo by #ag1 & ,mau!rrican by #bd1 feet2 :ile ! height ( ,mop5 seems to h be5 dim9i%$ by #d feet4 ,?us1 at fir/ sight1 ^! calculations appe> to indicate a g5]al elevation & ext5sion ( ! hills1 su* z might foll[ on a bulg+ upw>ds ( ! surface due to ! ext5sion ( a l>ge mass ( molt5 matt] und]gr\nd4 ,illu/ration3 ,,fig4 #gg4--,re-triangulation ( ,khasi hills4 7,oldham47 ,un=tunately1 z ,mr4 ,oldham %[s1 a v diff]5t1 & m probable1 int]pretation may be giv5 ( ^! results2 = all ! calculat$ *anges are r5d]$ unc]ta9 by ! *oice ( ! two /ations :i* =m ! ends ( ! new base-l9e4 ,"o at lea/ may h be5 displac$ by ! /ructural movem5ts )9 ! epic5tral area2 &1 moreov]1 ! l9e jo9+ !m runs ne>ly nor? & s\?4 ,z compression 9 ?is direction is to be expect$1 x is probable t ?is l9e 0 %ort5$2 & ! assumption t its l5g? 0 un*ang$ w\ld !re=e lead to an app>5t expansion ( all ! o!r sides4 ,! calculat$ *anges seem to fav\r ?is explanation to a great ext5t4 ,! sides jo9+ ,mop51 ,rangsanobo1 & ,?anj9a? run ne>ly ea/ & we/1 & are app>5tly l5g!n$ by #d4i & #c4d feet respectively2 :ile1 ( ! f\r sides jo9+ ^! /ations to ,mos+i & ,mun1 ly+ next to ! nor?1 two are ne>ly or q un*ang$1 & ! o!rs increas$ by #b4c & #c4b feet4 ,aga91 ! e/imat$ increase ( ! ,mos+i-,mun l9e is #d4d feet2 :ile ! f\r sides jo9+ ^! /ations to ! next nor!rly gr\p are increas$ by small am\nts--namely1 #a4b1 #b4f1-j4c1 & #b4d feet4 ,?us1 ! app>5t expansion t %\ld h occurr$ 9 ^! m or less nor!rly sides is less5$1 or r\ghly comp5sat$1 probably by a compression ( ! :ole region 9 a m]idianal direction4 ,= a simil> reason1 ! slight g5]al upheaval ( ! hills indicat$ by ! repeat$ calculations1 mu/ be reg>d$ z d\btful1 = x dep5ds on ! assum$ fixity ( ! /ation ( ,rangsanobo1 :]eas x is m probable t x 0 ! height ( ,t>amun ,tila t rema9$ un*ang$4 ,r$uc+ ! calculat$ heights ( all ! o!r /ations by six feet 7! assum$ rise ( ! latt]71 x foll[s t1 on ! :ole1 ! height ( ! ,khasi hills und]w5t b little *ange1 except at ,mau!rrican & ,l&au ,modo1 & ! second>y /ations ( ,mairang & ,kollong ,rock1 ne> ,maonoi4 ,! app>5t elevations ( #bd1 #ag1 #aa1 & #ae feet at ^! places exce$ ! probable error ( ! obs]vations2 & x is wor?y ( notice t all f\r /ations lie close to ! edge ( fault-sc>ps1 :ile ,l&au ,modo is n f> f two ( ! pools =m$ by di/ortion ( ! surface unaccompani$ by fault+4 ,if1 !n1 ! revis$ triangulation ( ! ,khasi hills has fail$ to provide absolute measures ( ! displacem5ts 9 ! epic5tral area1 x has1 nev]!less1 prov$ t important movem5ts1 bo? horizontal & v]tical1 h tak5 place4 ,di/ribution ( ! ,/ructural ,*anges4--,! b\nd>y ( ! epic5tral area1 z drawn 9 ,figs4 #fh & #ge1 lays no claim to great accuracy2 b its dep>ture f ! true l9e is probably 9 no place consid]able4 ,x mu/ evid5tly include all ! di/ricts :]e m>k$ /ructural *anges occurr$1 & mu/ !re=e ext5d ea/ ( ,maophlang & we/ ( ,tura4 ,t[>ds ! nor?1 ^! *anges h be5 trac$ to ! foot ( ! ,g>o hills1 & !re is "s1 ?\gh n v c]ta91 evid5ce ( alt]ations ( level along ! c\rse ( ! ,brahmaputra4 ,! v l>ge numb] ( aft]-%ocks record$ at ,borpeta & ,bijni also po9ts to an ext5sion ( ! epic5tral area beyond ^! places4 ,to ! ea/1 ! c\rse ( ! b\nd>y becomes d\btful1 b x mu/ pass close to ,gauhati & ea/ ( ,%illong1 & probably ends a %ort di/ance beyond ,ja9tiapur4 ,! s\!rn b\nd>y mu/ co9cide ne>ly ) ! nor? edge ( ! alluvial pla9s ( ,sylhet1 = !re is no evid5ce ( its intrusion into ! pla9s4 ,on ! we/ side1 ! epic5tral area includes ! ,g>o hills & "p ( ! alluvial pla9 to ! we/2 &1 f ! l>ge numb] ( aft]-%ocks felt at ,rangpur & ,kaunia1 & ! great viol5ce ( ! %ock at ! =m]1 we may inf] t bo? places lie )9 ! b\nd>y-l9e4 ,if1 !n1 !re is no great error 9 ! mapp+ ( ?is l9e1 x foll[s t ! epic5tre 0 ab\t #bjj miles long f ea/ to we/1 n less ?an #ej1 & possibly z mu* z #ajj1 miles 9 maximum wid?1 & conta9$ an area ( at lea/ #fjjj squ>e miles4 ,ne> ! b\nd>y1 ! p]man5t displacem5ts mu/ h be5 comp>atively small2 b !y 7 c]ta9ly m>k$ 9 ! nor!rn "p ( ! ,assam hills = a di/ance ( #ajj miles f ea/ to we/4 ,at ! limits ( ! latt] area1 z ,mr4 ,oldham rem>ks1 ! evid5ce po9ts to ! *anges be+ ( ! nature ( long1 l[ rolls1 ! *ange ( slope be+ insuffici5t to cause any appreciable *ange 9 ! dra9age *annels4 ,!n comes a zone 9 :i* ! surface *anges are m abrupt1 ! slopes ( ! /ream b$s h be5 alt]$ s z to cause conspicu\s *anges 9 ! nature ( ! /reams1 b any fracture or fault+ :i* may h tak5 place has di$ out be=e ! surface 0 rea*$4 ,& nor? ( ?is1 close to ! edge ( ! hills1 ! rocks h be5 fractur$ & fault$ "r up to ! surface4 ,,orig9 ,,( ,,! ,,e>?quake4 ,almo/ e feature ( ! great e>?quake po9ts to an orig9 v diff]5t f t ( ! o!rs describ$ 9 ?is volume4 ,! sudd5ness ) :i* ! %ock began1 its unusual duration1 & ! occurr5ce ( _m maxima ( int5sity1 are inconsi/5t ) a simple fault-displacem5t4 ,aga91 ! excessive velocities ( projection at ,rambrai & else:]e1 ! exi/5ce ( isolat$ fault-sc>ps & fractures1 ! local *anges ( level1 ! compression indicat$ by ! revis$ trigonometrical survey1 ! wide area ov] :i* ^! /ructural *anges took place1 & ! num]\s di/9ct c5tres ( subsequ5t activity1 all ^! ph5om5a demon/rate ! int5se & complex "* ( ! initial di/urbances1 z well z ! widespread bodily displacem5t ( ! e>?'s cru/ )9 ! epic5tral area4 ,!re may1 x is conceivable1 h be5 a numb] ( foci1 ne>ly or q deta*$ f "o ano!r1 & giv+ rise to a gr\p ( ne>ly concurr5t %ocks4 ,or--& ?is is a f> m probable supposition--!re may h be5 "o va/ deep-seat$ c5tre1 f :i* (f-%oots ran up t[>ds ! surface1 ea* p>tak+ to a great] or less degree 9 ! movem5t )9 ! p>5t focus4 ,z ,mr4 ,oldham po9ts out1 we h rec5tly become acqua9t$ ) a /ructure exactly correspond+ to t :i* is "h inf]r$4 ,! great ?ru/-planes1 s typically develop$ 9 ! ,scotti% ,highl&s1 are only rev]s$ faults :i* are ne>ly horizontal in/ead ( be+ highly incl9$2 & !y are accompani$ by a numb] ( ord9>y rev]s$ faults runn+ upw>ds to ! surface4 ,9 ,fig4 #gh1 ! ma9 features ( a section drawn by ! ,geological ,survey ( ,scotl& are reproduc$2 ,t1 ,t1 repres5t+ ?ru/ planes1 & t1 t1 m9or ?ru/s or faults4 ,a great movem5t along "o ( ! ma9 ?ru/-planes w\ld c>ry ) x dep5d5t slips along _m ( ! second>y planes4 ,direct effects ( ! =m] might be invisible at ! surface1 except 9 ! horizontal displacem5ts t w\ld be r5d]$ manife/ by a r5ew$ trigonometrical survey2 :]eas ! latt] might or might n rea* ! surface1 giv+ rise 9 ! "o case to fissures & fault-sc>ps1 9 ! o!r to local *anges ( level1 & 9 bo? to regions ( in/ability result+ 9 num]\s aft]-%ocks4 ,illu/ration3 ,,fig4 #gh4--;,diagram ( ,?ru/-planes4 ,! enorm\s dim5sions ( ! p>5t focus w be obvi\s f ! ph5om5a t h be5 describ$ above4 ,mr4 ,oldham has trac$ ! probable =m ( ! epic5tre4 ,x may 9 reality be nei!r s simple nor s symmetrical z is repres5t$ 9 ,fig4 #ge1 b !re are good reasons = ?9k+ t x does n diff] s5sibly ei!r 9 size or =m f t laid d[n4 ,! "p ( ! ?ru/-plane ov] :i* movem5t took place mu/ !re=e h be5 ab\t #bjj miles long1 n less ?an #ej miles wide1 & betwe5 #fjjj & #gjjj squ>e miles 9 area4 ,) reg>d to its dep?1 we h no decisive k4 ,x may h be5 ab\t five miles or less2 x c h>dly h be5 mu* great]4 ,x is a /ra9 on ! imag9ation to try & picture ! displacem5t ( s huge a mass4 ,we may ?9k1 if we w1 ( a slice ( rock ?ree or f\r miles 9 ?ickness & l>ge en\gh to rea* f ,dov] to ,exet] 9 "o direction & f ,london to ,brighton 9 ! o!r2 n slipp+ int]mitt5tly 9 diff]5t places1 b giv+ way almo/ in/antane\sly ?r\gh\t its :ole ext5t2 cru%+ all be=e x1 bo? solid rock & e>?y gr\nd alike2 &1 :e!r by ! sudd5 spr+ ( ! entire mass or by ! j> ( its hurtl+ fragm5ts1 %att]+ ! /ronge/ "w ( human h&s z easily z ! fraile/4 ,su* a ?ru/ might well be s5sible ov] half a cont95t1 & give rise to undulations :i*1 unse5 & unfelt1 might w5d _! way ar\nd ! globe4 ,,ref]5ces4 #a4 ,,agam5none1 ,g4--,notizie sui t]remoti oss]vati 9 ,italia durante l'anno #ahig 7,t]remoto dell' ,india poco dopo il mezzogiorno del #ab giugno74 ,ital4 ,sismol4 ,soc4 ,boll41 vol4 iii41 pte4 ii41 #ahig1 pp4 #bdi-bic4 #b4 ---- ,il t]remoto dell' ,india del #ab giugno #ahig4 ,ibid41 vol4 iv41 #ahih1 pp4 #cc-dj4 #c4 ---- ,eco 9 ,europa del t]remoto indiano del #ab giugno #ahig4 ,ibid41 vol4 iv41 #ahih1 pp4 #da-fg4 7,see also ! same volume1 pp4 #afg-agb47 #d4 ,,b>atta1 ,m4--,il gr&e t]remoto indiano del #ab giugno #ahig4 ,ital4 ,soc4 ,geogr4 ,boll41 vol4 x41 #ahig1 fasc4 viii4 #e4 ,,cancani1 ,a4--,i p5doli orizzontali del ,r4 ,oss]vatorio geod9amico di ,rocca di ,papa1 ed il t]remoto indiano del #ab giugno #ahig4 ,ital4 ,sismol4 ,soc4 ,boll41 vol4 iii41 #ahig1 pp4 #bce-bdj4 #f4 ,,hea?1 ,t4--,note on ! ,calcutta ,e>?quake 7,june #ab?1 #ahig7 z record$ by ! bifil> p5dulum at ! ,ed9burgh ,royal ,obs]vatory4 ,ed9b4 ,roy4 ,soc4 ,proc41 #ahig1 pp4 #dha-dhh4 #g4 ,,oldham1 ,r4,d4--,report on ! ,great ,e>?quake ( #ab? ,june #ahig4 ,mems4 ,geol4 ,surv4 ( ,india1 vol4 xxix41 #ahii1 pp4 i4-xxx41 #a-cgi1 ) #dd plates & #c maps4 #h4 ---- ,li/ ( ,aft]-%ocks ( ! ,great ,e>?quake ( #ab? ,june #ahig4 ,ibid41 vol4 xxx41 pt4 i41 #aijj1 pp4 #a-ajb4 #i4 ---- ,on ,tidal ,p]iodicity 9 ! ,e>?quakes ( ,assam4 ,j\rn4 ,asiat4 ,soc41 vol4 lxxi41 #aijb1 pp4 #aci-aec4 ,,footnotes3 #fi ,accord+ to "s reports1 ! e>?quake 0 felt 9 ,italy4 ,at ,livorno1 ! fir/ movem5ts 7 regi/]$ by seismographs at #aa4ag ,a4,m4 7,g4,m4,t471 & tremors 7 notic$ by "s p]sons at re/ at ab\t #aa4ae ,a4,m4 ,at ,sp9ea1 a s5sible undulatory %ock f s\?-ea/ to nor?-we/1 & la/+ ab\t f\r seconds1 0 felt at ! mom5t :5 all ! seismographs 7 set 9 motion by ! ,indian e>?quake4 ,9 spite ( ! great di/ance1 ! p]ception ( ! e>?quake 9 ,italy is n impossible1 b ! records seem to me to ref] to local tremors r ?an to ! v sl[ evanesc5t oscillations ( a v di/ant e>?quake4 #gj ,all ! times 9 ?is section are ref]r$ to ,madras mean "t1 :i* is #e;h4 #bjm4 #ei4bs4 9 advance ( ,gre5wi* mean "t4 ,9 ! next section x w be f\nd conv5i5t to use ! latt] /&>d4 #ga ,x may be useful to give ref]5ces to works 9 ,engli% 9 :i* ! pr9cipal in/rum5ts = regi/]+ di/ant e>?quakes are describ$4 ,= ,cancani's v]tical p5dulum1 see ,brit4 ,assoc4 ,rep41 #ahif1 pp4 #df-dg2 ,d>w9's bifil> p5dulum1 ,brit4 ,assoc4 ,rep41 #ahic1 pp4 #bia-cjc1 & ,nature1 vol4 #a41 #ahid1 pp4 #bdf-bdi2 ,milne's horizontal p5dulum1 ,seismology1 pp4 #eh-fa2 ,rebeur-,pas*witz's horizontal p5dulum1 ,brit4 ,assoc4 ,rep41 #ahic1 pp4 #cjc-cjh4 #gb ,! beg9n+s ( ! second & ?ird phases are %[n m cle>ly 9 ! record ( ! v]tical p5dulum at ,catania1 a record1 h[ev]1 t w n be> ! r$uction necess>y = ^! pages4 #gc ,geol4 ,mag41 vol4 x41 #ahic1 pp4 #cef-cfj4 #gd ,iri% ,acad4 ,trans41 vol4 xxi1 #ahdh1 p4 #eb4 #ge ,iri% ,acad4 ,trans41 vol4 xxi41 #ahdh1 pp4 #ee-eg4 #gf ,neapolitan ,e>?quake ( #aheg1 vol4 i41 #ahfb1 pp4 #cgf-cgh4 #gg ,japan ,seismol4 ,soc4 ,trans41 vol4 i41 pt4 ,,ii41 #ahhj1 pp4 #cc-ce4 #gh ,geol4 ,mag41 vol4 ix41 #ahhb1 pp4 #beg-bfe4 ,,*apt] ,x4 ,,conclusion4 ,9 ?is conclud+ *apt]1 ,i propose to give a summ>y ( ! results at :i* we h arriv$ f ! /udy ( rec5t e>?quakes1 & ?is c1 ,i ?9k1 be done be/ by describ+ :at may be reg>d$ z an av]age or typical e>?quake1 ?\gh x may be conv5i5t occasionally to dep>t slightly f su* a c\rse4 ,few %ocks h contribut$ m to our k ?an ! majority ( ^? describ$ 9 ?is volume2 b1 on c]ta9 po9ts1 we ga9 additional in=mation f ! inve/igation ( o!r e>?quakes1 & ^! are ref]r$ to :5 necess>y = ! purpose 9 view4 ,,=e-,,%ocks4 ,at ! outset1 we are met by a "q ( "s int]e/ & great practical importance--namely1 :e!r !re are any con/ant signs ( ! com+ ( great e>?quakes by means ( :i* _! occurr5ce might be pr$ict$ & _! disa/r\s effects mitigat$4 ,exclud+ ! ,is*ian e>?quakes1 :i* belong to a special class1 x is evid5t t !re is g5]ally "s slight prep>ation = a great e>?quake4 ,= a few h\rs or days be=eh&1 weak %ocks & tremors are felt or rumbl+ noises he>d )9 ! future meizoseismal area4 ,b1 un=tunately1 x has n yet be5 f\nd possible to di/+ui% ^! di/urbances f o!rs ( app>5tly ! same "* :i* occur alone1 s t = ! pres5t !y fail to s]ve z w>n+s4 ,9 ,japan1 :]e ! organisation ( e>?quake-/udies is m complete ?an else:]e1 x is possible t a vague =eca/ might be made1 if ! di/ribution ( ! =e-%ocks ( ! e>?quake ( #ahia %\ld prove to be a g5]al feature ( all great e>?quakes4 ,x 0 at fir/ suppos$ t ?is e>?quake occurr$ )\t prep>ation ( any k9d2 b a clos] analysis ( ! records %[s t dur+ ! previ\s two ye>s !re 0 a v decid$ increase 9 ! seismic activity ( ! di/rict1 & also t ! di/ribution ( ! epic5tres m>k$ out ! future fault-sc>p1 & at ! same "t exhibit$ a t5d5cy to comp>ative uni=mity ov] ! :ole fault-region4 ,= ! pres5t1 !n1 ! only w>n+ available is t giv5 by ! prelim9>y s\nd1 :i* may prec$e ! /ronge/ vibrations by z mu* z five or t5 or ev5 m seconds4 ,?\gh two or ?ree seconds may elapse be=e its "* is recognis$1 ! =e-s\nd ?us all[s "t = _m p]sons to escape f _! fall+ h\ses4 ,"s races1 h[ev]1 are less capable ( he>+ ! s\nd ?an o!rs1 & ?is may be "o reason :y ,japanese e>?quakes are s de/ructive ( human life4 ,,di/urb$ ,,area4 ,x is usual ) "s inve/igators to measure ! int5sity ( an e>?quake r\ghly by ! ext5t ( its di/urb$ area4 ,! dep? ( ! seismic focus mu/ ( c\rse h "s influ5ce on ! size ( ?is area1 & ?is condition is only neglect$ because we h no precise k ( ! dep? 9 any case4 ,?us1 ,mr4 ,oldham reg>ds ! ,indian e>?quake ( #ahig z rivall+ ! ,lisbon e>?quake ( #agee1 :i* is g5]ally consid]$ to hold ! fir/ place1 because its di/urb$ area 0 n c]ta9ly exce$$ by t ( ! latt]4 ,t di/urb$ area is1 h[ev]1 an untru/wor?y measure ( int5sity w be evid5t f ! foll[+ table1 9 :i* ! e>?quakes describ$ 9 ?is volume 7omitt+ ^? ( ,is*ia7 are arrang$ z ne>ly z may be 9 ord] ( int5sity1 beg9n+ ) ! /ronge/3-- ,e>?quake4 ,di/urb$ ,area 9 ,sq4 ,miles4 ,indian #a1gej1jjj ,japanese #ccj1jjj ,neapolitan #ci1bjj ,*>le/on #b1hjj1jjj ,rivi]a #bai1jjj ,&alusian #agd1jjj ,h]e=d #ih1jjj ,inv]ness #cc1jjj ,"h we see t ! ,*>le/on e>?quake 0 p]ceptible ov] a great] area ?an ! ,indian e>?quake1 :ile ! ,neapolitan e>?quake 0 inf]ior to t ( ,h]e=d 9 ?is respect4 ,! explanation ( c\rse is t ! b\nd>ies ( ! di/urb$ areas are isoseismal l9es correspond+ to diff]5t degrees ( int5sity1 ! inhabitants ( ,great ,brita9 & ! ,unit$ ,/ates be+ evid5tly m s5sitive to weak tremors1 or m obs]vant1 ?an ^? ( ,italy1 ,spa91 or ,c5tral ,asia4 ,! only di/urb$ areas t are b\nd$ by isoseismals ( ! same int5sity are ! two la/4 ,v r\ghly1 !n1 we may say t ! int5sity ( ! ,h]e=d e>?quake 0 ?ree times z great z t ( ! ,inv]ness e>?quake4 ,,position ,,( ,,! ,,epic5tre4 ,"o ( ! fir/ objects 9 ! inve/igation ( an e>?quake is to det]m9e ! position & =m ( ! epic5tre4 ,9 a few r>e cases1 z 9 ! ,japanese & ,indian e>?quakes1 :5 ! fault-sc>p is left protrud+ at ! surface1 only c>eful mapp+ is requir$ to asc]ta9 bo? data4 ,b1 9 ! great majority ( e>?quakes1 ! fault-slip dies out be=e rea*+ ! surface & ! position ( ! epic5tre is !n inf]r$ by me?ods dep5d+ *iefly on ! "t ( occurr5ce or on ! direction or int5sity ( ! %ock4 ,at fir/ sight1 me?ods t involve ! "t ( occurr5ce at diff]5t places seem to be ( consid]able promise4 ,no sci5tific in/rum5ts are s widely diffus$ z clocks & wat*es2 b1 on ! o!r h&1 few are s c>elessly adju/$4 ,x is ! exception1 r ?an ! rule1 to f9d a "t-record accurate to ! ne>e/ m9ute2 &1 z small errors 9 ! "t may be ( consequ5ce1 me?ods dep5d+ on ?is elem5t ( ! e>?quake are seldom employ$4 ,if1 h[ev]1 ! numb] ( obs]vations is l>ge = ! size ( ! di/urb$ area1 ! con/ruction ( coseismal l9es may def9e approximately ! position ( ! epic5tre4 ,9 ! ,h]e=d e>?quake ( #ahif1 ! c5tre ( ! inn]mo/ coseismal l9e 7,fig4 #fb7 is close to ! region ly+ betwe5 ! two epic5tres4 ,! me?od ( locat+ ! epic5tre by means ( ! int]section ( two or m l9es ( direction ( ! %ock 0 fir/ sugge/$ by ,mi*ell 9 #agfj1gi & has be5 employ$ by ,mallet 9 inve/igat+ ! ,neapolitan e>?quake1 by ,pr(essors ,t>amelli & ,m]calli 9 _! /udies ( ! ,&alusian & ,rivi]a e>?quakes1 z well z by o!r seismologi/s4 ,! div]sity ( app>5t directions at "o & ! same place caus$ its tempor>y neglect1 until ,pr(essor ,omori %[$ 9 #ahid t ! mean ( a l>ge numb] ( measurem5ts gives a tru/wor?y result 7p4 #ai74 ,8 int]e/+ obs]vations %\ld re9/ate ! me?od to its =m] place among ! m valuable in/rum5ts at ! disposal ( ! seismologi/4 ,no obs]vations1 h[ev]1 are at pres5t s valuable = ! purpose 9 view z ^? made on ! int5sity ( ! %ock4 ,= _m ye>s1 x has be5 ! cu/om to reg>d ! epic5tre z co9cid5t ) ! area ( greate/ damage to build+s2 &1 :5 ! area is small1 ! assumption _c be mu* 9 error4 ,x is ( c\rse m]ely a r\gh way ( obta9+ a result t is g5]ally giv5 m accurately by means ( isoseismal l9es2 b !re are exceptional cases1 su* z ! ,neapolitan & ,is*ian e>?quakes1 :5 ! de/ruction wr\ght by ! e>?quake furni%es evid5ce ( ! great] value4 ,a s+le isoseismal accurately drawn n only gives ! position ( ! epic5tre ) "s approa* to exactness1 b also by ! direction ( its long] axis det]m9es t ( ! orig9at+ fault4 ,:5 two or ?ree su* l9es c be trac$1 ! relative position supplies 9 addition ! hade ( ! fault 7p4 #bai74 ,! successful application ( ! me?od requires1 x is true1 a l>ge numb] ( obs]vations1 & ^! _c z a rule be obta9$ except 9 di/ricts t are some:at ?ickly & uni=mly populat$1 su* z ^? surr\nd+ ! cities ( ,h]e=d & ,inv]ness4 ,9 ! ,*>le/on e>?quake1 also1 ! position & =m ( ! epic5tres 7 d$uc$ f ! tr5d ( isoseismal l9es bas$ on ! damage to railway-l9es & v>i\s /ructures )9 a sp>sely inhabit$ meizoseismal area4 ,9 a few cases1 ( :i* ! ,indian e>?quake may be reg>d$ z typical1 a f\r? me?od has rec5tly be5 f\nd ( s]vice4 ,! num]\s aft]-%ocks :i* foll[ a great e>?quake orig9ate = ! mo/ "p )9 ! seismic focus ( ! latt]2 &1 z !y usually di/urb a v small area1 x is n difficult to asc]ta9 approximately ! positions ( _! epic5tres4 ,"s1 z 9 ! ,inv]ness aft]-%ocks ( #aija1 result f slips 9 ! v m>g9 ( ! pr9cipal focus2 b1 z a rule1 ! seat ( _! activity t5ds to contract t[>ds a c5tral region ( ! focus4 ,be>+ 9 m9d1 !n1 t "s ( ! succe$+ %ocks orig9ate at & beyond ! conf9es ( ! focus1 & t o!rs may be sympa!tic %ocks precipitat$ by ! sudd5 *ange ( /ress1 x foll[s t ! %ift+ epic5tres ( ! true aft]-%ocks map out1 9 "p at any rate1 ! epic5tral area ( ! pr9cipal e>?quake4 ,,dep? ,,( ,,! ,,seismic ,,focus4 ,x is mu* to be regrett$ t we h no satisfactory me?od ( det]m9+ s int]e/+ an elem5t z ! dep? ( ! seismic focus4 ,t x am\nts to b a few miles at ! mo/ is c]ta9 f ! limit$ areas )9 :i* slight %ocks are felt or disa/r\s ones exhibit _! maximum effects4 ,nor c we suppose t ! rocks at v great dep?s are capable ( (f]+ ! prolong$ resi/ance & sudd5 collapse "u /ress t are necess>y = ! production ( an e>?quake4 ,! problem is evid5tly beyond our pres5t p[]s ( solution1 & its int]e/ is !re=e ma9ly hi/orical4 ,all ! kn[n me?ods are vitiat$ by our ignorance ( ! refractive p[]s ( ! rocks trav]s$ by ! e>?-waves4 ,b1 ev5 if ?is ignorance c\ld be replac$ by k1 mo/ ( ! me?ods sugge/$ are op5 to objection4 ,falb's me?od1 dep5d+ on ! "t-int]val betwe5 ! initial epo*s ( ! s\nd & %ock1 is ( m ?an d\btful value4 ,dutton's1 bas$ on ! rate ( *ange ( surface-int5sity1 is difficult to apply1 & 9 any case gives only an inf]ior limit to ! dep?4 ,"t-obs]vations h be5 employ$1 especially 9 ,new ,zeal&2 b ! unc]ta9ty 9 select+ ?r\gh\t ! same phase ( ! movem5t1 & ! l>ge errors 9 ! e/imat$ dep? result+ f small errors 9 ! "t-records1 are at pres5t mo/ s]i\s objections4 ,!re rema9s ! me?od devis$ by ,mallet1 &1 ?\gh he claim$ = x an exagg]at$ accuracy1 x /ill1 9 my op9ion1 holds ! field aga9/ all its successors4 ,:5 c>efully appli$1 z x has be5 by ,mallet himself1 by ,john/on-,lavis & ,m]calli1 we probably obta9 at lea/ "s conception ( ! dep? ( ! seismic focus4 ,pr(essor ,omori & ,mr4 ,k4 ,hirata h rec5tly#hj less5$ ! *ief difficulty 9 ! application ( ,mallet's me?od4 ,!y h d$uc$ ! angle ( em]g5ce f ! v]tical & horizontal compon5ts ( ! motion z regi/]$ by seismographs1 in/ead ( f ! incl9ation ( fissures 9 damag$ walls4 ,9 two rec5t e>?quakes record$ at ,miyako 9 ,japan1 !y f9d ! angle ( em]g5ce to be #g4b & #i respectively1 ! correspond+ dep?s ( ! foci be+ #e4f & #i4c miles4 ,^! are probably ! mo/ accurate e/imates t we possess1 & x w be not$ t !y diff] little f ! mean values obta9$ = ! ,neapolitan1 ,&alusian1 & ,rivi]a e>?quakes--namely1 #f4f1 #g4f1 & #aj4h miles4 ,,nature ,,( ,,! ,,%ock ,9 "o respect1 ! e>?quakes describ$ above fail to repres5t ! progress ( mod]n seismology4 ,!y furni% no diagrams made by accurately con/ruct$ seismographs )9 _! di/urb$ areas4 ,! curve reproduc$ 9 ,fig4 #cf1 z already po9t$ out1 is no exception to ?is /atem5t4 ,= ano!r reason1 ! records t 7 obta9$ 9 ,japan ( ! e>?quake ( #ahia are tru/wor?y = little m ?an ! %ort-p]iod initial vibrations2 =1 ow+ to ! passage ( ! surface-waves1 visible 9 & ne> ! meizoseismal area1 ! ,japanese seismographs regi/]$ ! tilt+ ( ! gr\nd r ?an ! ela/ic vibrations t trav]s$ ! e>?'s cru/4 ,not)/&+ ?is defect1 p]sonal impressions ( an e>?quake-%ock give a fairly accurate1 if incomplete1 idea ( its nature4 ,ne>ly all obs]v]s plac$ "u fav\rable conditions agree t an e>?quake beg9s ) a deep rumbl+ s\nd1 accompani$1 aft] ! fir/ second or two1 by a fa9t tremor :i* gradually1 & sometimes rapidly1 increases 9 /r5g? until x m]ges into ! %ock prop]1 :i* consi/s ( sev]al or _m vibrations ( l>g] amplitude & long] p]iod1 & dur+ :i* ! att5dant s\nd is g5]ally at its l\de/2 ! e>?quake dy+ away1 z x began1 ) tremors & a l[ rumbl+ s\nd4 ,illu/ration3 ,,fig4 #gi4--,seismographic ,record ( ,tokio ,e>?quake ( #ahid4 7,omori47 ,! vibrations t produce ! s5sible %ock are by no means all t are pres5t dur+ an e>?quake4 ,! ,indian e>?quake1 = in/ance1 seem$ to la/ ab\t ?ree or f\r m9utes at ,midnapur2 b ! movem5ts ( ! bubble ( a level %[$ t ! gr\nd cont9u$ to oscillate = at lea/ five m9utes long] 7p4 #bhj74 ,_m ( ^! unfelt waves are r5d]$ manife/ by seismographs1 al?\gh !re are /ill o!rs t elude regi/ration ei!r f ! extreme %ortness or ! great l5g? ( _! p]iods4 ,9 ,fig4 #gi is %[n ! pr9cipal "p ( a diagram obta9$ at ,tokio dur+ ! ,japanese e>?quake ( ,june #bj?1 #ahid 7p4 #ah71 ! curve repres5t+ ! ,n4,e4-,s4,w4 compon5t ( ! horizontal motion dur+ ! fir/ #be seconds ( ! record4 ,! in/rum5t employ$ is "o specially design$ = regi/]+ /rong e>?quakes1 & is unaffect$ by v m9ute tremors4 ,^? :i* =m$ ! comm5cem5t ( ?is e>?quake la/$ = ab\t #aj seconds1 z %[n by ord9>y seismographs1 & ! vibrations _h atta9$ a range ( a few millimetres be=e !y affect$ ! in/rum5t 9 "q4 ,= ! fir/ #b-a_/b seconds1 !y occurr$ at ! rate ( f\r or five a second4 ,! motion !n sudd5ly became viol5t1 & ! gr\nd 0 displac$ #cg mm4 9 "o direction1 foll[$ by a return movem5t ( #gc mm41 & ?is aga9 by "o ( #db mm41 ! complete p]iod ( ! oscillation be+ #a4h seconds4 ,! succe$+ vibrations 7 ( small] amplitude & g5]ally ( %ort] p]iod = a m9ute & a half1 !n dy+ out dur+ ! la/ ?ree m9utes z almo/ imp]ceptible waves ) a p]iod ( two or m seconds4#ha ,?\gh incomplete 9 "s respects1 ?is diagram illu/rates cle>ly ! division ( ! e>?quake-motion into ?ree /ages--namely1 ! prelim9>y tremors1 ! pr9cipal portion or mo/ active "p ( an e>?quake1 & ! end-portion or gradually evanesc5t sl[ undulations4 ,9 all ?ree /ages1 h[ev]1 bo? tremors & sl[ undulations may be pres5t2 &1 z ! latt]1 ow+ to _! long p]iod1 are m or less ins5sible to human be+s1 ! ripples ( ! f9al /age give ! impression ( a tremul\s t]m9ation z describ$ above4 ,! duration ( ea* /age v>ies consid]ably 9 diff]5t e>?quakes4 ,?us1 9 a valuable /udy ( #bg e>?quakes record$ at ,miyako1 9 ,japan1 dur+ ! ye>s #ahif-ih1 ,messrs4 ,omori & ,hirata %[#hb t ! duration ( ! prelim9>y /age v>ies f #j to #bf seconds1 ) an av]age ( ab\t #aj seconds2 t ( ! pr9cipal portion f #j4g to #bf seconds1 also ) an av]age ( ab\t #aj seconds2 & t ( ! end portion f #bh & #aje seconds1 ) an av]age ( ab\t "o m9ute4 ,! total app>5t duration1 h[ev]1 dep5ds on ! in/rum5t employ$2 "o ( ! e>?quakes1 t ( ,april #bcrd1 #ahih1 di/urb+ ! seismograph at ,miyako = two m9utes2 :ile1 at ,tokio1 a horizontal p5dulum design$ by ,pr(essor ,omori oscillat$ = at lea/ two h\rs4 ,! p]iods ( bo? ripples & sl[ undulations1 aga91 v>y f "o e>?quake to ano!r2 b x is wor?y ( notice t ! av]age p]iod ( ! undulations is almo/ con/ant 9 all ?ree /ages ( ! motion1 be+ #a4a1 #a4c1 & #a4c seconds1 respectively1 = ! ea/-we/ compon5t ( ! horizontal motion1 & #a4j second ?r\gh\t = ! nor?-s\? compon5t4 ,= ! ripples1 ! av]age p]iod is 4#jh second 9 ! prelim9>y /age1 4#aj second 9 ! pr9cipal portion1 & 4#jh second aga9 9 ! end portion2 ^? ( ! pr9cipal portion be+ slightly l>g] 9 amplitude1 z well z long] 9 p]iod1 ?an ! ripples ( ! fir/ & ?ird /ages4 ,,s\nd-,,ph5om5a4 ,besides ! ripples already m5tion$1 !re are o!rs ( /ill small] amplitude & %ort] p]iod t are s5sible1 b z a rule only j s5sible1 to u z s\nds4 ,all ! kn[n evid5ce po9ts to ! extraord9>y l[ness ( ! e>?quake-s\nd4 ,accord+ to "s obs]v]s1 x seems z if close to _! l[] limit ( audibility2 :ile o!rs1 h[ev] int5tly !y may li/51 are unable to he> ! slighte/ noise4 ,9 o!r words1 ! mo/ rapid vibrations pres5t 9 an e>?quake d n recur at a rate ( mu* m ?an ab\t #cj to #ej p] second2 or1 if !y d1 !y are n /rong en\gh to impress ! human e>4 ,to mo/ obs]v]s1 ! s\nd seems to increase & decrease 9 int5sity ) ! %ock1 & s gradually & smoo?ly does ?is *ange take place t ! s\nd is frequ5tly mi/ak5 = t ( an und]gr\nd tra9 approa*+ ! obs]v]'s h\se1 pass+ b5ea? x1 & rec$+ 9 ! opposite direction4 ,"s p]sons1 especially if situat$ )9 ! meizoseismal area1 he> also l\d cra%es 9 ! mid/ ( ! rumbl+ s\nd & simultane\sly ) ! /ronge/ vibrations4 ,at a mod]ate di/ance1 say f #cj to #dj miles1 ! s\nd becomes m h>% & grat+ :ile ! %ock is felt2 &1 at a great] di/ance1 ev5 ?is *ange disappe>s1 & no?+ is he>d b an almo/ monoton\s s\nd l ! l[ roll ( di/ant ?und]4 ,! explanation ( ?is is t ! s\nd-vibrations are ( diff]5t p]iods & v>y+ amplitude1 & ! limit+ vibrations t5d to become inaudible ) increas+ di/ance1 ! l[] on acc\nt ( _! long p]iod1 ! high] ow+ to _! small amplitude4 ,! magnitude ( ! s\nd-area dep5ds1 ev5 m ?an t ( ! di/urb$ area1 on ! p]sonal equation ( ! obs]v]s4 ,! l[] limit ( audibility v>ies n only 9 diff]5t individuals1 b also 9 diff]5t races4 ,9 ,great ,brita91 x is d\btful :e!r an e>?quake ev] occurs unaccompani$ by s\nd2 & 9 ! meizoseismal area ! noise is he>d by ne>ly all obs]v]s4 ,) ,italians1 ! av]age l[] limit ( audibility is high] ?an ) ! ,anglo-,saxon race2 slight %ocks frequ5tly occur )\t noticeable s\nd1 b ) /rong ones1 ! l>g] numb] ( obs]v]s is sure to include "o or m capable ( he>+ ! rumbl+ noise4 ,! ,japanese are1 h[ev]1 seldom affect$ by ! mo/ rapid e>?quake-vibrations1 & ! /ronge/ %ocks may be unatt5d$ by any record$ s\nd4 ,! result is manife/ 9 ! size ( ! s\nd-area 9 diff]5t c\ntries4 ,9 ! ,h]e=d e>?quake1 ! s\nd-area conta9$ #gj1jjj squ>e miles2 9 ! ,neapolitan e>?quake1 ab\t #c1cjj squ>e miles2 :ile1 9 ,japanese e>?quakes1 ! s\nd is r>ely he>d m ?an a few miles f ! epic5tre4 ,ano!r effect ( ?is p]sonal equation ( ! obs]v]s is t ! s\nd-vibrations app>5tly outrace ^? ( long] p]iod4 ,! ,italians1 = in/ance1 g5]ally he> ! s\nd t prec$es ! %ock1 & m r>ely ! weak] s\nd t foll[s x4 ,9 ,japan1 only ! e>li] s\nd-vibrations1 if any1 seem to be audible4 ,9 ,great ,brita91 on ! contr>y1 ! =e-s\nd is p]ceptible to f\r1 & ! aft]-s\nd to ?ree1 out ( e five obs]v]s2 & ^! proportions are ma9ta9$ r\ghly to consid]able di/ances f ! epic5tre4 ,x foll[s1 !re=e1 t ! s\nd-vibrations & ^? :i* con/itute ! %ock mu/ travel ) ne>ly1 if n q1 ! same velocity2 & t ! great] duration ( ! s\nd is due ei!r to ! prolongation ( ! initial movem5t or to ! ov]lapp+ ( ! pr9cipal focus by ! s\nd-focus4 ,nei!r alt]native c be reg>d$ z improbable1 b obs]vations made on ,briti% e>?quakes po9t to ! latt] explanation z ! true "o4 ,x w be suffici5t to ref] to two ph5om5a 9 support ( ?is /atem5t4 ,9 ! fir/ place1 ! p]c5tage ( obs]v]s :o he> ! =e-s\nd v>ies ) ! direction f ! epic5tre4 ,?us1 dur+ ! ,inv]ness e>?quake ( #aija1 ! majority ( obs]v]s 9 ,ab]de5%ire reg>d$ ! s\nd z beg9n+ & end+ ) ! %ock2 :ile1 9 c\nties ly+ m ne>ly along ! c\rse ( ! great fault1 ! s\nd 0 g5]ally he>d bo? be=e & aft] ! %ock 7p4 #bec74 ,9 ?is case1 !n1 ! initial & conclud+ s\nd vibrations mu/ h come *iefly f ! m>g9s ( ! seismic focus2 & ^? f ! m>g9 ne>e/ to an obs]v] w\ld be m s5sible ?an ^? f ! f>!r m>g94 ,aga91 9 slight e>?quakes1 su* z ! ,cornwall e>?quake ( ,april #a1 #ahih1hc ! curves ( equal s\nd int5sity1 :ile _! axes are p>allel to ^? ( ! isoseismal l9es1 are displac$ lat]ally ) respect to ^! curves1 ow+ to ! arrival ( ! /ronge/ s\nd-vibrations f ! upp] m>g9 ( an incl9$ seismic focus4 ,:5 a fault-slip occurs1 ! displacem5t is obvi\sly greate/ 9 ! c5tral region1 & dies out gradually t[>ds ! m>g9s ( ! focus4 ,! ph5om5a describ$ above %[ t ! evanesc5t displacem5t )9 ^! m>g9s g5]ate s\nd-vibrations only2 & t ! great] slip )9 ! c5tral region produces also ! m important vibrations t compose ! %ock4 ,z ! =m] are p]ceptible ov] a limit$ di/rict1 :ile ! latt] may be felt ?r\gh half a cont95t1 x is cle> t ! s\nd-area %\ld be> no fix$ relation 9 po9t ( size to ! di/urb$ area1 b %\ld be comp>atively great] = a slight %ock ?an = a /rong "o4 ,,velocity ,,( ,,! ,,e>?-,,waves4 ,if we consid] only ! e>?quakes "h describ$1 we see at once h[ great is ! div]sity 9 ! e/imat$ velocity ( ! e>?-waves4 ,on ! "o h&1 we h a value z high z #e4b kms4 p] sec4 = ! ,*>le/on e>?quake1 &1 at ! o!r end ( ! scale1 a value ( #j4i km4 p] sec4 = ! ,h]e=d e>?quake4 ,betwe5 !m1 & equally tru/wor?y1 lie ! e/imates ( #c4j km4 p] sec4 = ! ,indian e>?quake1 & #b4a kms4 p] sec4 = ! ,japanese e>?quake & its imm$iate successors4 ,x is difficult to acc\nt entirely = su* discordance4 ,errors ( obs]vation may be responsible = a small "p ( ! diff]5ces4 ,! initial /r5g? ( ! di/urbance appe>s to h "s effect1 & ! nature ( ! rocks trav]s$ mu/ be a factor ( consequ5ce :5 ! di/ances 9 "q are n v great4 ,9 ! ,japanese & ,h]e=d e>?quakes1 all ?ree may h comb9$ to produce ! div]g5t results1 ! di/ance 9 ^! cases be+ only #bge & #adb kms4 respectively4 ,9 ! ,indian & ,*>le/on e>?quakes1 ! di/ances are mu* great] 7#aidd & #adhg kms471 & ! v>iety ( rocks trav]s$ mu/ t5d to give a tru] av]age4 ,9 ! =m]1 ! result obta9$ 7#c4j kms4 p] sec47 agrees s closely ) ! velocity ( ! long-p]iod undulations ( di/ant e>?quakes z to sugge/ t x 0 ^! waves t 7 tim$ at ! /ations we/ ( ,calcutta & di/urb$ ! magnetographs at ,bombay4#hd ,omitt+1 !n1 ! ,indian e/imate1 we f9d t1 = ! ,japanese & ,*>le/on e>?quakes1 ! velocity increases ) ! di/ance z measur$ along ! surface4 ,to a c]ta9 ext5t1 su* a result might h be5 expect$1 _h we assum$ ! e>?quake-waves to travel along ! *ords jo9+ ! focus to v di/ant places ( obs]vation4 ,! wave-pa?s t p5etrate ! e>? are /raight l9es1 h[ev]1 only :5 ! conditions t det]m9e ! velocity are uni=m ?r\gh\t1 & su* uni=mity we h no reason to expect4 ,f :at we "k ( ! e>?'s int]ior1 !re c1 inde$1 be little d\bt t ! velocity ( e>?quake-waves increases ) ! dep? bel[ ! surface1 & t ! wave-pa?s 9 consequ5ce are curv$ l9es ) _! convexity d[nw>ds4 ,x w\ld be out ( place to /ate m ?an ! pr9cipal result ( ! rec5t inve/igations by ,dr4 ,a4 ,s*midt#he & ,pr(4 ,p4 ,rudzki#hf on ?is subject4 ,^! are bas$ on ! assumptions t ! velocity increases ) ! dep? bel[ ! surface1 & t x is always ! same at ! same dep?4 ,f ! focus ( ! e>?quake1 wave-pa?s div]ge 9 all directions4 ,^? :i* />t horizontally curve upw>ds1 & int]sect ! surface ( ! e>? 9 a circle divid+ ! :ole surface into two areas ( v unequal size4 ,)9 ! small area1 ! surface-velocity is inf9ite at ! epic5tre1 & decreases outw>ds until x is lea/ on ! b\nd>y-circle4 ,9 ! l>g] region beyond1 ! surface-velocity increases ) ! di/ance f ! epic5tre1 until1 at ! antipodes ( t po9t1 x is aga9 inf9ite4 ,b1 z ! dep? ( ! focus is always slight comp>$ ) ! radius ( ! e>?1 ! small circul> area surr\nd+ ! epic5tre is practically negligible1 & we may reg>d ! surface-velocity ( ! waves t trav]se ! body ( ! e>? z a quantity t cont9ually increases ) ! di/ance f ! epic5tre4 ,h[ fully ?is int]e/+ !oretical result has be5 confirm$ is well %[n 9 ,mr4 ,oldham's rec5t & v valuable inve/igation on ! propagation ( e>?quake-motion to great di/ances4#hg ,a /udy ( ! records ( ! ,indian e>?quake reveal$ ! exi/5ce ( ?ree s]ies ( waves1 ! fir/ two consi/+ 9 all probability ( longitud9al & transv]sal waves travell+ ?r\gh ! body ( ! e>?1 & ! ?ird ( undulations spread+ ov] its surface 7pp4 #bhb-bhe74 ,ext5d+ 8 inquiries to t5 o!r e>?quakes orig9at+ 9 six diff]5t c5tres1 ,mr4 ,oldham di/+ui%es ! same ?ree phases 9 _! movem5ts2 ! ?ird phase be+ ! mo/ con/antly record$1 ! second less s1 :ile ! fir/ phase is ! mo/ frequ5tly abs5t4 ,) ! exception ( a few v div]g5t records1 ! initial times ( ^! phases & ! maximum epo* ( ! ?ird phase are plott$ on ! accompany+ diagram 7,fig4 #hj71 9 :i* di/ances f ! epic5tre 9 degrees ( arc are repres5t$ along ! horizontal l9e & ! "t-int]val 9 m9utes along ! p]p5dicul> l9e4 ,! dots ne> ! two l[] curves ref] to ! records ( ! heavily weight$ ,italian in/rum5ts1 & ! crosses to ^? ( ! light horizontal p5dulums1 :i* respond some:at irregul>ly to ! motion ( ! fir/ two phases 7p4 #bhb74 ,9 ! ?ird phase1 !re is less div]g5ce betwe5 ! indications ( ! two classes ( in/rum5ts1 & dots are us$ 9 ea* case = ! initial1 & crosses = ! maximum epo*4 ,illu/ration3 ,,fig4 #hj4--,"t-curves ( pr9cipal epo*s ( e>?quake-waves ( di/ant orig94 7,oldham47 ,( ! smoo!d curves drawn betwe5 ^! s]ies ( po9ts1 ^? m>k$ ,a1 ,b1 & ,c repres5t ! "t-curves ( ! beg9n+s ( ! fir/1 second1 & ?ird phases respectively1 :ile ,d is ! "t-curve = ! maximum ( ! ?ird phase4 ,! concavity ( ! two l[] l9es t[>ds ! horizontal base-l9e %[s t ! surface-velocity ( ! correspond+ waves increases rapidly ) ! di/ance1 f> m s ?an w\ld be possible ) rectil9e> motion4 ,! rates at :i* ^! waves travel ?r\gh ! e>? !re=e increase ) ! dep?1 & ! wave-pa?s mu/ 9 consequ5ce be curv$ l9es convex t[>ds ! c5tre ( ! e>?4 ,if ! "t-curves ,a & ,b 7 cont9u$ backw>ds to ! orig91 _! incl9ations at t po9t to ! horizontal l9e give ! initial velocities ( ! correspond+ waves1 :i* prove to be ab\t #e & #c kms4 p] sec4 respectively4 ,n[1 accord+ to rec5t exp]im5ts made by ,mr4 ,h4 ,nagaoka on ! ela/ic con/ants ( rocks1#hh ! mean velocity ( sev5 ar*aean rocks is #e4a kms4 p] sec4 = ! longitud9al waves1 & #b4h kms4 p] sec4 = ! transv]sal waves--values :i* agree s closely ) ^? obta9$ = ! fir/ two s]ies ( e>?quake-waves z to leave little d\bt ) reg>d to _! "*4 ,! o!r "t-curves1 ,c & ,d1 correspond+ to ! initial & maximum epo*s ( ! ?ird phase1 are practically /raight l9es4 ,"s ( ! records are slightly discordant = ! av]age curve1 especially = ! initial epo*2 b x is (t5 difficult to def9e ! comm5cem5t ( ?is phase ) precision4 ,at any rate1 ! obs]vations %[ no di/9ct sign ( an increase 9 ! surface-velocity ( ^! waves ) ! di/ance f ! orig94 ,x may !re=e be conclud$ t !y travel along ! surface ) velocities :i* are practically con/ant = ea* individual e>?quake1 ! l>ge/ waves at ! rate ( ab\t #b4i kms4 p] sec41 & ! advance waves ) a velocity ( ab\t #c4c kms4 p] sec41 ris+ occasionally to ov] #d4j kms4 p] sec4 ,,/ructural ,,*anges ,,9 ,,! ,,epic5tral ,,area4 ,*anges ( elevation h long be5 kn[n z accompanim5ts ( great e>?quakes1 ?\gh _m ( ! e>li] obs]vations & measurem5ts left mu* to be desir$ 9 accuracy & complet5ess4 ,! ,japanese e>?quake ( #ahia1 h[ev]1 plac$ ! reality ( su* movem5ts beyond d\bt1 & reveal$ ! exi/5ce ( a fault-sc>p1 ) a height 9 "o place ( #ah or #bj feet1 & a l5g? ( at lea/ #dj1 if n ( #gj1 miles4 ,9 ! ,indian e>?quake ( #ahig1 ! fault-sc>ps 7 %ort]1 ?\gh m pron\nc$ 9 "*1 ! l>ge/ kn[n 7! ,*$rang fault7 be+ ab\t #ab miles long1 & hav+ a maximum ?r[ at ! surface ( #ce feet4 ,9 "s o!r rec5t e>?quakes1 also1 rem>kable fault-sc>ps h be5 develop$4 ,aft] ! great %ocks felt 9 ,ea/]n ,greece on ,april #bj? & #bg?1 #ahid1 a fissure 0 trac$ = a di/ance ( ab\t #cd miles1 runn+ 9 an ea/-s\?-ea/ & we/-nor?-we/ direction ?r\gh ! epic5tral di/rict1 & v>y+ 9 wid? f an in* or two to m ?an ?ree y>ds4 ,t x 0 a fault1 & n an ord9>y fissure1 0 evid5t f its great l5g?1 its uni=m direction1 & its indep5d5ce ( geological /ructure4 ,! ?r[ 0 g5]ally small1 9 no place exce$+ five feet4#hi ,aga91 9 ,briti% ,balu*i/an1 aft] ! sev]e e>?quake ( ,decemb] #bj?1 #ahib1 a fre% crack 0 obs]v$ 9 ! gr\nd runn+ = sev]al miles 9 a /raight l9e p>allel to ! axis ( ! ,khojak range4 ,x co9cid$ almo/ exactly ) a l9e ( spr+s1 & 0 cle>ly produc$ by a fre% slip along an old l9e ( fault1 = be=e ! e>?quake x _h ! appe>ance ( an old road1 & ! natives ass]t t ! gr\nd has always crack$ along ?is l9e ) e sev]e %ock4 ,9 #ahib1 ! *ange 9 relative height ( ! two sides ( ! fault 0 small1 9 "o place :]e x 0 measur$ be+ only two in*es4#ij ,b o!r *anges1 besides ^? 9 a v]tical direction1 occasionally take place2 ?\gh1 ow+ to _! rec5t discov]y1 comp>atively few examples are z yet kn[n4 ,:ile ! ?r[ ( ! ,japanese fault v>i$ greatly 9 am\nt1 & once ev5 9 direction1 !re 0 also a con/ant %ift t[>ds ! nor?we/ ( ! gr\nd on ! nor?-ea/ side ( ! fault1 ! displacem5t at "o spot be+ z mu* z #ac feet4 ,9 ! fault-sc>p =m$ 9 #ahid 9 ,ea/]n ,greece1 a simil> %ift took place1 ?\gh to :at ext5t is unkn[n4 ,!re is1 moreov]1 evid5ce ( actual compression ( ! e>?'s cru/ at "r angles to ! fault-l9e4 ,! ,neo valley1 trav]s$ by ! ,japanese fault1 0 app>5tly n>r[] aft] ! e>?quake ?an x 0 be=e1 & plots ( gr\nd 7 r$uc$ f #dh to #cj feet 9 l5g?--i4e41 by ne>ly #dj p] c5t4 ,9 ,briti% ,balu*i/an1 ! =mation ( ! fissure ref]r$ to above 0 accompani$ bo? by compression p]p5dicul>1 & by %ift+ p>allel1 to ! fault4 ,! actual displacem5t 9 ea* direction is unkn[n1 b ! resultant 0 n less ?an #bg in*es4 ,!re c be no d\bt t a fault-sc>p is =m$ 9 ! fir/ place ) great rapidity4 ,s abrupt1 inde$1 7 ! /ructural displacem5ts 9 ! epic5tral area ( ! ,indian e>?quake1 t !y contribut$ v mat]ially to ! int5sity ( ! %ock1 giv+ rise to ! excessive velocities obs]v$ at ,rambrai & else:]e 7p4 #bgc74 ,! gr[? ( ! sc>p does n1 h[ev]1 always cease ) ! fir/ great e>?quake1 ?\gh x may take place 9 a contr>y s5se1 z 9 ! elevation connect$ ) ! ,conception e>?quake ( #ahce4 ,! pr9cipal %ock1 accord+ to ,d>w91 0 foll[$ dur+ ! few succe$+ days by "s hundr$ m9or ones 7?\gh ( no inconsid]able viol5ce71 :i* seem$ to come f ! same qu>t] f :i* ! fir/ _h proce$$2 :il/1 on ! o!r h&1 ! level ( ! gr\nd 0 c]ta9ly n rais$ by !m2 b1 on ! contr>y1 aft] an int]val ( "s weeks1 x /ood r l[] ?an x did imm$iately aft] ! great convulsion4#ia ,,aft]-,,%ocks4 ,a s]ies ( aft]-%ocks1 m or less long1 is a con/ant att5dant on e great tectonic e>?quake1 & few are ! e>?quakes ( any degree ( /r5g? t c be reg>d$ z completely isolat$4 ,ev5 9 ^? :i* visit ?is c\ntry1 aft]-%ocks are seldom abs5t4 ,= in/ance1 conf9+ ourselves to ! la/ few ye>s1 ! ,pembroke e>?quake ( #ahib 0 foll[$ by #h %ocks1 ! ,inv]ness e>?quake ( #ahij by at lea/ #aj1 & possibly by #ai %ocks1 & t ( ! same di/rict 9 #aija by #ae well-def9$ aft]-%ocks 9 addition to _m o!rs record$ by "o obs]v]4 ,( #cjj ,italian e>?quakes /rong en\gh to cause "s damage to build+s1 ,dr4 ,cancani f9ds t e "o 0 ei!r prec$$ or foll[$1 & *iefly foll[$1 by its own tra9 ( m9or %ocks4 ,= "s h\rs1 & ev5 = days1 aft] a great e>?quake1 ! %ocks are s num]\s t x is (t5 impossible to keep c\nt ( !m4 ,_m local c5tres spr+ into activity 9 diff]5t p>ts ( ! epic5tral area2 &1 ?\gh only ! /ronge/ %ocks c be id5tifi$ else:]e1 x is cle> t z a rule ! %ocks felt at any "o /ation are q di/9ct f ^? obs]v$ at ano!r4 ,! enorm\s numb] ( aft]-%ocks t foll[ "s e>?quakes c only be realis$ :5 !y are subject$ to cont9u\s seismographic regi/ration2 &1 ev5 !n1 c\ntless e>?-s\nds & ! slighte/ tremors mu/ escape detection4 ,! %ocks may1 inde$1 succe$ "o ano!r s rapidly t "o beg9s be=e ano!r ends1 & ! result is an almo/ incessant tremul\s motion r5d]$ manife/ by ! quiv]+ ( wat]-surfaces or ! sw++ ( *&eli]s4 ,( ! total numb] ( aft]-%ocks1 we may =m "s idea f rec5t records 9 ,japan4 ,aft] ! ,m9o-,ow>i e>?quake ( #ahia1 #c1cfe %ocks 7 record$ )9 little m ?an two ye>s at ,gifu1 & #a1bih at ,nagoya1 b nei!r ( ^! figures includes ! %ocks felt )9 ! fir/ few h\rs4 ,( ! ,kumamoto e>?quake ( ,july #bh?1 #ahhi1 ! aft]-%ocks record$ at ,kumamoto until ! end ( #ahic am\nt to #ibb2 & ^? ( ! ,kago%ima e>?quake ( ,septemb] #g?1 #ahic1 record$ at ,*iran until ! end ( ,janu>y #ahid1 to #dhj4 ,dur+ ! fir/ #cj days1 ! numb]s record$ 7 #a1gdf at ,gifu1 #cdj at ,kumamoto1 & #bgh at ,*iran2 %[+1 z ,pr(essor ,omori rem>ks1 t ! aft]-%ocks dim9i% 9 frequ5cy ) ! size ( ! di/urb$ areas1#ib--;i4e41 r\ghly ) ! initial int5sity ( ! %ocks4 ,next to absolute numb]1 ! rapid decl9e 9 g5]al frequ5cy is ! mo/ m>k$ *>act]i/ic ( aft]-%ocks4 ,pr(essor ,omori has %[n t1 exclud+ m9or oscillations1 x foll[s ! law repres5t$ geographically by ! curves 9 ,fig4 #ea1 & algebraically by ! equation y k _/ 7h x71 :]e y is ! frequ5cy at "t x & h & k are con/ants = "o & ! same e>?quake4 ,by means ( ?is =mula1 x is possible to e/imate r\ghly ! int]val ( "t t mu/ elapse be=e ! seismic activity ( ! c5tral di/rict resumes its normal value4 ,= ! ,m9o-,ow>i e>?quake1 ?is proves to be ab\t =ty ye>s1 = ! ,kumamoto e>?quake ab\t sev5 or eight ye>s1 & = ! ,kago%ima e>?quake ab\t ?ree or f\r ye>s4 ,9 a rec5t memoir on ,italian aft]-%ocks1#ic ,dr4 ,cancani has urg$ t o!r factors besides initial int5sity det]m9e ! duration ( a seismic p]iod1 & prom95tly among ^! he places ! dep? ( ! seismic focus4 ,:5 ! dep? is v small1 ! duration ( ! p]iod is %ort1 n mu* m ?an t5 days2 :5 ! dep? is mod]ate1 ! duration may ext5d to ?ree mon?s2 &1 :5 great1 x may am\nt to sev]al ye>s4 ,! pr9cipal law t gov]ns ! di/ribution ( aft]-%ocks 9 "t may be reg>d$ z well-e/abli%$4 ,x is o!rwise ) reg>d to _! di/ribution 9 space4 ,?is has be5 exam9$ only 9 ! cases ( ! ,japanese e>?quake ( #ahia & ! ,inv]ness e>?quake ( #aija4 ,s f> z we c judge f ! evid5ce :i* !y furni%1 aft]-%ocks appe> to be mo/ num]\s )9 & ne> ! c5tral portion ( ! seismic focus2 ?\gh ! area ( maximum activity is subject to cont9ual oscillation4 ,9 ?is region1 also1 !re is evid5ce ( a gradual decrease 9 ! dep?s ( ! aft]-%ock foci2 :ile1 ne> ! extremities ( ! epic5tral area1 !re occur di/ricts ( slightly great] frequ5cy ?an else:]e4 ,) ! lapse ( "t1 !re seems !re=e to be a con/ant ext5sion1 bo? upw>ds & longitud9ally1 ( ! area ov] :i* ! pr9cipal fault-slip took place4 ,,orig9 ,,( ,,e>?quakes4 ,9 ! introductory *apt]1 a brief sket* is giv5 ( ! diff]5t causes to :i* e>?quakes are assign$4 ,) ^? due to rock-falls 9 subt]ranean *annels1 we ne$ h little to d4 ,! %ocks are inv>iably slight1 & ! "p !y play 9 ! %ap+ ( ! e>?'s cru/ is insignificant4 ,volcanic e>?quakes possess a high] degree ( int]e/4 ,!y repres5t1 no d\bt1 incipi5t or unsuccessful attempts to produce an eruption4 ,!y may be ! =]unn]s ( a great cata/rophe4 ,( f> high] importance 9 ! hi/ory ( our globe is ! ?ird class ( e>?quakes1 includ+ all ^? connect$ ) ! manifold *anges :i* ! cru/ has und]gone4 ,9 ! sl[ anneal+ process1 to :i* x has be5 subject$ f ! e>lie/ times1 ! cru/ has be5 crumpl$ & fractur$1 elevat$ into ! l(tie/ m\nta9 ranges or depress$ bel[ ! level ( ! sea4 ,e sudd5 yield+ "u /ress is ! cause ( an e>?quake4 ,x is *iefly1 p]haps almo/ entirely1 9 ! =mation ( faults t ?is yield+ is manife/$4 ,! initial fractur+ may be ! cause ( "o or _m %ocks1 b inf9itely ! l>g] numb] mu/ be ref]r$ to ! sl[ gr[? ( ! fault1 ! int]mitt5t slips1 n[ 9 "o "p1 n[ 9 ano!r1 :i*1 aft] ! lapse ( ages1 culm9ate 9 a great displacem5t4 ,( ! l5g? ( "t occupi$ 9 ! =mation ( a s+le fault1 we c make no e/imate 9 ye>s4 ,! anticl9al fault ( ,*>nwood ,=e/ dates f a pre-c>bonif]\s p]iod4 ,9 #ahic x _h n ceas$ to gr[4#id ,/ill less c we conceive1 h[ev] fa9tly1 ! numb] ( elem5tal slips t con/itute ! hi/ory ( a s+le fault4 ,we may ?9k1 if we please1 ( ! #adc tremors & e>?-s\nds not$ at ,comrie 9 ,p]?%ire dur+ ! la/ ?ree mon?s ( #ahci1 ( ! #cjf e>?quakes felt 9 ! ,isl& ( ,zante dur+ ! ye> #ahif1 or ! #a1gdf %ocks record$ at ,gifu dur+ ?irty days 9 #ahia2 b we %all be z f> z ev] f realis+ ! va/ numb] ( /eps involv$ 9 ! gr[? ( a fault1 let alone a m\nta9-*a94 ,yet1 all ov] ! l&-surface ( ! globe1 ! cru/ is int]sect$ by numb]less faults1 & h>dly any portion is !re 9 :i* "s or _m ( ^! faults are n gr[+4 ,"o c\ntry1 inde$1 su* z ,great ,brita91 may h rea*$ a condition ( comp>ative /agnancy2 ! fault-slips are few & slight1 & e>?quakes 9 consequ5ce are r>e & g5]ally inconspicu\s4 ,9 ano!r1 l ,ea/]n ,japan & ! adjo9+ ocean-b$1 ! movem5ts are frequ5t1 occasionally almo/ incessant1 & few ye>s pass )\t "s great convulsion by :i* cities are wreck$ & hundr$s ( human lives are lo/4 ,at su* times1 we magnify ! rle ( e>?quakes1 & are 9 "s dang] ( =gett+ t1 9 ! =mation ( a m\nta9-*a9 or cont95t1 !y s]ve no high] purpose ?an ! creak+ ( a :eel 9 ! complex movem5ts ( a great ma*9e4 ,,footnotes3 #gi ,phil4 ,trans41 vol4 li41 pt4 ii41 #agfa1 pp4 #fbe-fbf4 #hj ,j\rn4 ,sci4 ,coll4 ,imp4 ,univ41 ,tokyo1 vol4 xi41 #ahii1 pp4 #aid-aie4 #ha ,j\rn4 ,coll4 ,sci4 ,imp4 ,univ41 ,tokyo1 vol4 vii41 pt4 v41 #ahid1 pp4 #a-d2 ,ital4 ,sismol4 ,soc4 ,boll41 vol4 ii41 #ahif1 pp4 #ahj-ahh4 #hb ,j\rn4 ,coll4 ,sci4 ,imp4 ,univ41 ,tokyo1 vol4 xi41 #ahii1 pp4 #afa-aie4 #hc ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 lvi41 #aijj1 pp4 #a-g4 #hd ,!re is no reason :y ! surface-undulations ( ! ,indian e>?quake %\ld n h produc$ a s5sible %ock ev5 z f> z ,italy4 ,tak+ _! amplitude 9 t c\ntry at #ejh mm4 & _! p]iod at #bb sec4 7p4 #bhc71 ! maximum accel]ation w\ld be ab\t #dj mm4 p] sec41 correspond+ to ! int5sity #b ( ! ,rossi-,=el scale4 7,am]4 ,j\rn4 ,sci41 vol4 xxxv41 #ahhh1 p4 #dbi47 #he ,nature1 vol4 lii41 #ahie1 pp4 #fca-fcc4 #hf ,g]l&'s ,beitrge zur ,geophysik1 vol4 iii41 pp4 #dhe-eah4 #hg ,phil4 ,trans41 #aijj;,a1 pp4 #ace-agd4 #hh ,publ4 ( ,e>?q4 ,inves4 ,com4 9 ,=4 ,langs4 7,tokyo71 ,no4 #d1 #aijj1 pp4 #dg-fg4 #hi ,s4,a4 ,papavasili\1 ,p>is1 ,acad4 ,sci41 ,compt4 ,r5d41 vol4 cxix41 #ahid1 pp4 #aab-aad1 #chj-cha4 #ij ,geol4 ,mag41 vol4 x41 #ahic1 pp4 #cef-cfj4 #ia ,geol4 ,soc4 ,trans41 vol4 v41 #ahdj1 pp4 #fah-fai4 #ib ,! di/urb$ areas ( ^! e>?quakes conta9$1 respectively1 #bba1jjj1 #ci1jjj1 & #cj1jjj squ>e miles4 #ic ,boll4 ,sismol4 ,soc4 ,ital41 vol4 viii41 #aijb1 pp4 #ag-dh4 #id ,roy4 ,soc4 ,proc41 vol4 lvii41 #ahie1 pp4 #hg-ie4 ,,index4 ,accel]ation1 maximum1 ( wave-motion 9 ,japanese e>?quake1 #ahd1 #ahe2 9 ,indian e>?quake1 #bgb ,aft]-%ocks1 def9ition1 #d2 frequ5cy1 #aih1 #bef1 #bif1 #cdd2 di/ribution 9 space1 #bjj1 #bjc1 #bih1 #cbf1 #cde2 s\nd-ph5om5a1 #bjg1 #cjj2 connection ) fault-sc>ps1 #cjj2 outl9+ ( epic5tre by1 #cbf2 orig9 (1 #beg2 ( ,neapolitan e>?quake1 #dj2 ( ,is*ian e>?quakes1 #ef1 #fe2 ( ,&alusian e>?quake1 #ig2 ( ,*>le/on e>?quake1 #acc2 ( ,rivi]a e>?quake1 #afg2 ( ,japanese e>?quake1 #aih2 ( ,h]e=d e>?quake1 #bdj2 ( ,inv]ness e>?quake1 #bef2 ( ,indian e>?quake1 #bif2 ( ,briti% e>?quakes1 #cdc2 ( ,italian e>?quakes1 #cdc2 ( ,japanese e>?quakes1 #cdd ,agam5none1 ,g41 #ic1 #id1 #aja1 #cai ,alluvium1 displacem5t (1 by ,indian e>?quake1 #bhg ,amplitude ( wave-motion1 def9ition1 #d2 9 ,neapolitan e>?quake1 #cd2 9 ,japanese e>?quake1 #ahe2 9 ,indian e>?quake1 #bgj ,&alusian e>?quake1 prep>ation =1 #ge2 inve/igation (1 #gf2 damage caus$ by1 #gg2 isoseismal l9es & di/urb$ area1 #gh2 ! unfelt e>?quake1 #hb2 position ( epic5tre1 #hd2 dep? ( focus1 #he2 nature ( %ock1 #hg2 s\nd-ph5om5a1 #ia2 velocity ( e>?-waves1 #ib2 connection betwe5 geological /ructure & int5sity ( %ock1 #ie2 fissures1 #if2 l&slips1 #ig2 effect on und]gr\nd wat]1 #ig2 aft]-%ocks1 #ig2 orig9 (1 #ii2 bibliography1 #aja ,animals1 effects ( e>?quakes on1 #adc ,balu*i/an e>?quake ( #ahib1 #bhh1 #cda ,baldacci1 ,l41 #gj1 #gc ,b>atta1 ,m41 #cbj ,b>rois1 ,c41 #gf ,b]g]on1 ,c41 #gf ,b]telli1 ,t41 #age ,b]tr&1 ,m41 #gf ,birds1 effects ( e>?quakes on1 #adc ,bordw>1 cru/-fracture at1 #cji ,bron1 ,r41 #gf ,burton1 ,w4,k41 #bad ,cancani1 ,a41 #bha1 #bhb1 #cbj1 #cdc1 #cde ,ca/ro1 ,m4,f4 de1 #gf1 #aja ,*>le/on e>?quake1 inve/igation (1 #ajb2 damage caus$ by1 #ajc2 isoseismal l9es & di/urb$ area1 #ajd2 prep>ation =1 #ajg2 nature ( %ock1 #ajh2 d\ble epic5tre1 #aaa2 orig9 ( d\ble %ock1 #abj2 dep? ( foci1 #abb2 velocity ( e>?-waves1 #abf2 fissures1 #acj2 s&-crat]s1 #acj2 effects on human be+s1 #aca2 feel+ ( nausea1 #acb2 aft]-%ocks1 #acc2 orig9 (1 #acd2 bibliography1 #acg ,*>lon1 ,e41 #age ,*$rang1 fault-sc>p at1 #cjd ,clocks1 untru/wor?9ess ( "t-records ( /opp$1 #ci1 #id1 #aba1 #abg ,cond]1 ,j41 #agg1 #bac ,coseismal l9es1 #bbg1 #cbd ,covelli1 ,n41 #fg1 #fi ,damage caus$ by ,neapolitan e>?quake1 #aj1 #bd2 by ,is*ian e>?quakes1 #ej1 #ef2 by ,&alusian e>?quake1 #gg2 by ,*>le/on e>?quake1 #ajc2 by ,rivi]a e>?quake1 #aci2 by ,japanese e>?quake1 #aha2 by ,h]e=d e>?quake1 #bag2 by ,inv]ness e>?quake1 #bdg ,d>w91 ,h41 #bha ,daubre1 ,a41 #gc ,davison1 ,c1 #bjb-bjf1 #bjh1 #baj1 #bac1 #bae-bfa1 #bie ,dea?-rate ( ,neapolitan e>?quake1 #bd2 ( ,is*ian e>?quakes1 #ej1 #ef2 ( ,&alusian e>?quake1 #gg2 ( ,*>le/on e>?quake1 #ajd2 ( ,rivi]a e>?quake1 #adj2 ( ,japanese e>?quake1 #ahb ,d5za1 ,f41 #aee1 #age ,dep? ( seismic focus1 me?ods ( det]m9+1 #be1 #hf1 #abb1 #cbf2 ( ,neapolitan e>?quake1 #bh2 ( ,is*ian e>?quakes1 #ed1 #fa2 ( ,&alusian e>?quake1 #hf2 ( ,*>le/on e>?quake1 #abb1 #abe2 ( ,rivi]a e>?quake1 #aej2 ( ,japanese e>?quakes1 #cbh ,d]by e>?quake ( #aijc1 #bcf ,direction ( %ock1 #bb1 #cc1 #ahf1 #bbe1 #cbe ,di/urb$ area1 def9ition (1 #c2 ( ,neapolitan e>?quake1 #aj2 ( ,is*ian e>?quakes1 #ea1 #eh2 ( ,&alusian e>?quake1 #hj2 ( ,*>le/on e>?quake1 #ajg2 ( ,rivi]a e>?quake1 #ade2 ( ,japanese e>?quake1 #ahc2 ( ,h]e=d e>?quake1 #bai2 ( ,inv]ness e>?quake1 #bdi2 ( ,indian e>?quake1 #bfe2 connection betwe5 int5sity ( %ock &1 #cbc ,dolomieu1 #aa ,du ,bois1 ,f41 #gc ,dutton1 ,c4,e41 #ajc-acg ,dutton's me?od ( det]m9+ dep? ( seismic focus1 #abb1 #cbg ,e>?quake-motion1 nature (1 #bhj1 #bhb1 #cbh1 #ccj1 #ccg2 propagation (1 to great di/ances1 #ccg ,e>?-s\nd1 def9ition (1 #d ,ed9burgh1 record ( ,indian e>?quake at1 #bha1 #bhc1 #bhe ,ellis1 ,w41 #hc ,em]g5ce1 angle (1 #ac ,epic5tre1 def9ition (1 #c2 me?ods ( det]m9+ position (1 #ad1 #eb1 #fj1 #cbd2 ( ,neapolitan e>?quake1 #bb1 #bc2 ( ,is*ian e>?quakes1 #ec1 #fj1 #fg2 ( ,&alusian e>?quake1 #hd2 ( ,*>le/on e>?quake1 #aaa2 ( ,rivi]a e>?quake1 #adf2 ( ,h]e=d e>?quake1 #bbd2 ( ,inv]ness e>?quake1 #bdh2 ( ,indian e>?quakes1 #bfd1 #bgf1 #cjb ,epomeo1 #de1 #fa1 #ga ,falb's me?od ( det]m9+ dep? ( seismic focus1 #hf1 #cbg ,fall5 pill>s1 evid5ce (1 #ag1 #ai ,fault1 orig9at+1 ( ,h]e=d e>?quake1 #bai2 ( ,inv]ness e>?quake1 #bdi ,fault-sc>p ( ,japanese e>?quake1 #ahi2 g5]al appe>ance1 #ahi2 l5g?1 #aib2 ?r[1 #aic2 horizontal %ift1 #aic2 c\rse1 #aic2 swamp =m$ by x1 #aid ,fault-sc>ps ( ,indian e>?quakes1 #bgc1 #cjd2 ,*$rang fault1 #cjd2 ,sam9 fault1 #cjh2 ( ,greek e>?quake ( #ahid1 #cdj1 #cda2 ( ,balu*i/an e>?quake ( #ahic1 #cda1 #cdb2 =mation & gr[? (1 #cdb ,fault-slips1 tectonic e>?quakes due to1 #e1 #dc1 #ajj1 #ace1 #agd1 #baa1 #bai1 #bbd1 #bda1 #bdi1 #bee1 #cag1 #cdf ,fi%es1 de/ruction (1 by ,rivi]a e>?quake1 #afb ,fissures1 caus$ by ,&alusian e>?quake1 #if2 by ,*>le/on e>?quake1 #acj2 by ,inv]ness e>?quake1 #bdg2 by ,indian e>?quake1 #bhe ,focus1 seismic1 def9ition (1 #c ,focus1 seismic1 dep? (1 me?ods ( det]m9+1 #be1 #hf1 #abb1 #cbf2 ( ,neapolitan e>?quake1 #bh2 ( ,is*ian e>?quakes1 #ed2 ( ,&alusian e>?quake1 #hf2 ( ,*>le/on e>?quake1 #abb1 #abe2 ( ,rivi]a e>?quake1 #aej2 ( ,japanese e>?quakes1 #cbh ,focus1 dim5sions ( seismic1 ( ,h]e=d e>?quake1 #bbd2 ( ,inv]ness e>?quake1 #bej ,=e-%ocks1 #cba2 ( ,neapolitan e>?quake1 #dj2 ( ,is*ian e>?quake1 #eg2 ( ,&alusian e>?quake1 #gf2 ( ,*>le/on e>?quake1 #ajg2 ( ,rivi]a e>?quake1 #adb2 ( ,japanese e>?quake1 #bja2 ( ,h]e=d e>?quake1 #bci2 ( ,inv]ness e>?quake1 #bdf ,f\qu1 ,f41 #gf1 #hd1 #aja ,fracture1 cru/-1 at ,bordw>1 #cji ,fractures 9 build+s1 evid5ce (1 #ad1 #ae1 #bf ,fu*s1 ,c4,w4,c41 #ajb ,galli1 ,i41 #hb ,geological /ructure & int5sity ( %ock1 connection betwe51 #ie1 #ajf1 #aac1 #aae1 #ace1 #afd1 #bfe ,gifu1 records ( ,japanese aft]-%ocks at1 #ahc1 #aig ,gray1 ,t41 #bie ,great ,gl5 fault & ,inv]ness e>?quakes1 connection betwe51 #bde ,greek e>?quake ( #ahid1 fault-sc>p (1 #cdj ,hayd51 ,e41 #ajc ,hea?1 ,t41 #bhc1 #cbj ,h]e=d e>?quake1 inve/igation (1 #bae2 prep>ation =1 #bae1 #bch2 isoseismal l9es & di/urb$ area (1 #baf2 damage caus$ by1 #bag1 #bid2 position ( orig9at+ fault1 #bai2 nature ( %ock1 #bbj2 orig9 ( d\ble s]ies ( vibrations1 #bbc2 position & dim5sions ( ! two foci1 #bbd2 direction ( ! %ock1 #bbe2 coseismal l9es & velocity ( e>?-waves1 #bbg2 s\nd-ph5om5a1 #bbi2 isac\/ic l9es & s\nd-area1 #bcd2 =e-%ocks1 #bch2 aft]-%ocks1 #bdj2 orig9 ( e>?quake1 #bdj2 bibliography1 #bfa ,hills1 *anges 9 aspect (1 aft] ,indian e>?quake1 #caa ,hirata1 ,k41 #cbg1 #cca ,human be+s1 effects ( ,*>le/on e>?quake on1 #aca ,hypoc5tre1 #c ,ib]ian p59sula1 e>?quakes (1 #ge ,indian e>?quake1 inve/igation (1 #bfb2 isoseismal l9es & di/urb$ area1 #bfd2 nature ( %ock1 #bff2 visible e>?-waves1 #bfh2 elem5ts ( wave-motion1 #bgj2 s\nd-ph5om5a1 #bgd2 velocity ( e>?-waves1 #bge2 ! unfelt e>?quake1 #bhj2 e>?-fissures1 #bhe2 displacem5ts ( alluvium1 #bhg2 s&-v5ts1 #bhh2 rise ( riv]-b$s1 etc41 #bij2 l&slips1 #bia2 rotation ( pill>s1 #bic2 aft]-%ocks1 #bif2 /ructural *anges 9 epic5tral area1 #cja1 #cae2 /ructure ( epic5tral di/rict1 #cjb2 fault-sc>ps1 #cjd2 cru/-fractures1 #cji2 lakes & pools n due to fault+1 #caj2 *anges 9 aspects ( hills1 #caa2 revision ( trigonometrical survey1 #cab2 orig9 ( e>?quake1 #cag2 bibliography1 #cai ,inv]ness e>?quake1 prep>ation =1 #bdf2 damage caus$ by1 #bdg2 fissure 9 gr\nd1 #bdg2 isoseismal l9es & di/urb$ area1 #bdg2 position ( orig9at+ fault1 #bdi2 nature ( %ock1 #bej2 s\nd-ph5om5a1 #bec2 orig9 ( e>?quake1 #bee2 aft]-%ocks & _! orig91 #bef2 sympa!tic e>?quakes1 #bei2 comp>ison ) ,japanese e>?quake1 #bfj2 bibliography1 #bfa4 ,inve/igation1 ,mallet's me?ods (1 #ab1 #ba ,isac\/ic l9es1 #bcd2 ( ,h]e=d e>?quake1 #bce2 ( ,d]by e>?quake1 #bcf ,is*ia1 volcanic hi/ory (1 #de1 #gj2 *>act]i/ics ( eruptions1 #di2 seismic hi/ory1 #di ,is*ian e>?quake ( #ahha1 inve/igation (1 #ej2 isoseismal l9es & di/urb$ area1 #ea2 position ( epic5tre1 #eb2 dep? ( focus1 #ed2 nature ( %ock1 #ee2 aft]-%ocks1 #ef2 orig9 (1 #gj2 bibliography1 #gc ,is*ian e>?quake ( #ahhc1 inve/igation (1 #ef2 prep>ation =1 #eg2 isoseismal l9es & di/urb$ area1 #eh2 position ( epic5tre1 #fj2 dep? ( focus1 #fa2 nature ( %ock1 #fd2 l&slips1 #fd2 aft]-%ocks1 #fe2 orig9 (1 #gj2 bibliography1 #gc ,is*ian e>?quakes1 *>act]i/ics (1 #ff2 orig9 (1 #gj ,isoseismal l9es1 def9ition (1 #c2 _! use 9 det]m9+ position ( epic5tre1 #bai1 #bdi1 #cbe2 ( ,neapolitan e>?quake1 #i2 ( ,is*ian e>?quakes1 #ea1 #eh2 ( ,&alusian e>?quake1 #gh2 ( ,*>le/on e>?quake1 #ajd2 ( ,rivi]a e>?quake1 #adc2 ( ,japanese e>?quake1 #agh1 #ahb2 ( ,h]e=d e>?quake1 #baf2 ( ,inv]ness e>?quake1 #bdg2 ( ,indian e>?quake1 #bfd ,issel1 ,a41 #aci1 #afc1 #afd1 #aff1 #age ,japanese e>?quake ( #ahhg1 #ah ,japanese e>?quake ( #ahia1 inve/igation (1 #agg2 /ructure ( meizoseismal area1 #agi2 damage caus$ by1 #aha2 isoseismal l9es & di/urb$ area1 #ahb2 nature ( %ock1 #ahd2 ! great fault-sc>p1 #ahi2 m9or %ocks1 #aig2 di/ribution ( aft]-%ocks 9 "t1 #aih2 prep>ation =1 #bja2 di/ribution ( aft]-%ocks 9 space1 #bjc2 s\nd-ph5om5a ( aft]-%ocks1 #bjg2 sympa!tic e>?quakes1 #bji2 orig91 (1 #baa2 bibliography1 #bac ,japanese e>?quake ( #ahid1 #ah1 #cbi ,john/on-,lavis1 ,h4,j41 #ej-gb1 #cbg ,kilian1 ,w41 #gf ,koto1 ,b41 #agg1 #ahj1 #aha1 #ahd1 #aij-aif1 #bji1 #bab1 #bac ,lakes =m$ by b5d+ ( riv]-b$ dur+ ,indian e>?quake1 #caj ,lakes =m$ by fault-sc>p ( ,japanese e>?quake1 #aid2 ( ,indian e>?quake1 #cje ,l&slips caus$ by ,is*ian e>?quake1 #fd2 by ,&alusian e>?quake1 #ig2 by ,indian e>?quake1 #bia ,lvy1 ,m41 #gf ,lisbon e>?quake ( #agee1 #ge1 #hb ,mc,gee1 ,w4,j41 #acd ,macph]son1 ,j41 #aja ,magnetographs1 e>?quakes record$ by1 #hb1 #aeg1 #afj1 #ahi1 #bgg1 #bhb ,mallet1 ,r41 #g-dd1 #he1 #ajb1 #abd1 #aej1 #bid-bif1 #cbe ,mallet's me?od ( det]m9+ dep? ( focus1 #be1 #cbg ,masato1 ,h41 #agh1 #bac ,masc>t1 ,e41 #aei1 #afj ,may ,hill anticl9al & ,h]e=d e>?quake1 connection betwe51 #bdb ,meizoseismal area1 def9ition (1 #c2 ( ,&alusian e>?quake1 #ii2 ( ,japanese e>?quake1 #agi ,m]calli1 ,g41 #aa1 #eg1 #eh1 #fj1 #fa1 #fc1 #fg1 #gj-gc1 #gf1 #hj1 #hd1 #he1 #hh1 #ij1 #aja1 #ach-age1 #cbe1 #cbg ,mi*ell1 ,j41 #cbe ,milne1 ,j41 #ce1 #agg1 #aha1 #ahb1 #ahf1 #ahi1 #bjj1 #bac1 #bha1 #bhc ,m9or %ocks ( ,neapolitan e>?quake1 #dj2 ( ,japanese e>?quake1 #aig ,m\nta9 ranges1 effect (1 on int5sity ( %ock1 #ie1 #ajf ,m\reaux1 ,t41 #afa ,nagaoka1 ,h41 #agg1 #bad1 #cci ,nagoya1 records ( ,japanese aft]-%ocks at1 #ahc1 #aig ,nature ( %ock1 ,neapolitan e>?quake1 #cj2 ,is*ian e>?quakes1 #ee1 #fd2 ,&alusian e>?quake1 #hg2 ,*>le/on e>?quake1 #ajh2 ,rivi]a e>?quake1 #aej2 ,japanese e>?quake1 #ahd2 ,h]e=d e>?quake1 #bbj2 ,inv]ness e>?quake1 #bej2 ,indian e>?quake1 #bff ,nausea1 feel+ (1 caus$ by ,*>le/on e>?quake1 #acb ,neapolitan e>?quake1 inve/igation (1 #g1 #ab2 isoseismal l9es & di/urb$ area1 #i2 damage caus$ by1 #aj2 position ( epic5tre1 #ad2 dep? ( focus1 #be2 nature ( %ock1 #cj2 s\nd-ph5om5a1 #cg2 velocity ( e>?-waves1 #ci2 m9or %ocks1 #dj2 orig91 #da2 bibliography1 #dd ,ness1 ,lo*1 connection betwe5 ,inv]ness e>?quakes & =mation (1 #bee1 #beg1 #bfa ,nogus1 ,a4,f41 #aja ,oddone1 ,e41 #age ,(fret1 ,a41 #gf1 #aeh1 #aei1 #age ,oglialoro1 ,a41 #gc ,oldham1 ,r4,d41 #bfb-cbj1 #ccg1 #cdj ,omori1 ,f41 #ai1 #bj1 #agg1 #ahc-ahf1 #ahh1 #aig-aii1 #bjg1 #bad1 #bfb1 #cbe1 #cbg1 #cbi1 #cca ,orig9 ( e>?quakes1 #b1 #e1 #cde2 ( ,neapolitan e>?quake1 #da2 ( ,is*ian e>?quakes1 #gj2 ( ,&alusian e>?quake1 #aja2 ( ,*>le/on e>?quake1 #acd2 ( ,rivi]a e>?quakes1 #agd2 ( ,japanese e>?quake1 #baa2 ( ,h]e=d e>?quake1 #bdj2 ( ,inv]ness e>?quake1 #bee2 ( ,indian e>?quake1 #cag ,ov]turn$ bodies1 maximum accel]ation d$uc$ f1 #ahd1 #bgb ,palmi]i1 ,l41 #eg1 #gb1 #gc ,p]iodicity ( ,japanese aft]-%ocks1 #aii ,p]rey1 ,a41 #g ,pot5za1 evid5ce ( damag$ *ur* at1 #ae1 #bf ,pr$iction ( e>?quakes1 possible1 #cbb ,prep>ation = e>?quakes1 #dj1 #eg1 #gf1 #ajg1 #adb1 #bja1 #bch1 #bdf1 #cba ,rails1 flexure (1 by ,*>le/on e>?quake1 #aab2 by ,japanese e>?quake1 #ahb2 by ,indian e>?quake1 #bhh ,railway-tunnels1 obs]vations ( ,rivi]a e>?quake 91 #aff ,rebeur-,pas*witz1 ,e4 von1 #bha ,riv]-b$s1 rise (1 caus$ by ,indian e>?quake1 #bij ,rivi]a e>?quake1 inve/igation1 #ach2 damage caus$ by1 #aci2 prep>ation =1 #adb2 isoseismal l9es & di/urb$ area1 #adc2 position ( epic5tre1 #adf2 dep? ( pr9cipal focus1 #adi2 nature ( %ock1 #aej2 s\nd-ph5om5a1 #aef2 ! unfelt e>?quake1 #aeg2 effects ( e>?quake at sea1 #afb2 de/ruction ( fi%es1 #afb2 seismic sea-waves1 #afc2 connection betwe5 geological /ructure & int5sity ( %ock1 #afd2 obs]vations 9 railway-tunnels1 #aff2 aft]-%ocks1 #afg2 rec5t movem5ts 9 ! ,rivi]a1 #agj2 seismic hi/ory ( ! ,rivi]a1 #aga2 orig9 (1 #aga2 bibliography1 #age ,rocca di ,papa1 record ( ,indian e>?quake at1 #bha1 #bhb1 #bhe ,rossi1 ,m4,s4 de1 #eg1 #gd1 #hb1 #aja1 #age ,rossi-,=el scale ( seismic int5sity1 #ajd1 #baf1 #bdg ,rotation ( pill>s1 caus$ by ,h]e=d e>?quake1 #bid2 by ,indian e>?quake1 #bic2 explanation (1 #bie ,rudzki1 ,p41 #ccf ,rumi1 ,pr(41 #afi ,sam91 fault-sc>p at1 #cjh ,s&-crat]s caus$ by ,*>le/on e>?quake1 #acj2 by ,indian e>?quake1 #bhh ,s*midt1 ,a41 #ccf ,seismic sea-waves ( ,rivi]a e>?quake1 #adb1 #afc ,seismic v]tical1 #ab1 #bi1 #fb ,seismographic records ( ,rivi]a e>?quake1 #aed2 ( ,japanese e>?quake ( #ahid1 #cbi ,sekiya1 ,s41 #ah1 #ai ,s]pi]i1 ,a41 #gd ,%illong1 nature ( ,indian e>?quake at1 #bff ,sloan1 ,e41 #ajc1 #aag-aai1 #acd1 #ace ,s\nd-area1 def9ition (1 #c2 ( ,neapolitan e>?quake1 #ch2 ( ,&alusian e>?quake1 #ib2 ( ,h]e=d e>?quake1 #bcd2 ( ,inv]ness e>?quake1 #beb2 ( ,indian e>?quake1 #bge ,s\nd-ph5om5a1 nature ( s\nd1 #ch1 #bbi1 #beb1 #ccb2 inaudibility to "s obs]v]s1 #bca1 #bgd2 its cause1 #bcc2 isac\/ic l9es1 #bcd-bcf2 v>iations 9 nature ( s\nd ?r\gh\t s\nd-area1 #bcg2 "t-relation ( s\nd & %ock1 #bch1 #bec2 orig9 ( e>?quake-s\nds1 #ccd2 s\nd-ph5om5a ( ,neapolitan e>?quake1 #cg2 ( ,&alusian e>?quake1 #ia2 ( ,*>le/on e>?quake1 #acc2 ( ,rivi]a e>?quake1 #aef2 ( ,japanese aft]-%ocks1 #bjg2 ( ,h]e=d e>?quake1 #bbi2 ( ,inv]ness e>?quake1 #beb2 ( ,indian e>?quake1 #bgd ,/ructural *anges1 di/ribution (1 9 ,indian e>?quake1 #cae ,subsultory %ock1 #e ,sympa!tic e>?quakes ( ,japanese e>?quake1 #bji2 ( ,inv]ness e>?quake1 #bei ,tanakadate1 ,a41 #agg1 #bad ,t>amelli1 ,t41 #gf1 #hd1 #he1 #hh1 #ij1 #aja1 #ach1 #aej1 #afe1 #age1 #cbe ,tectonic e>?quakes1 #e ,?ru/-plane1 ,indian e>?quake due to movem5t along1 #cah ,"t-curve ( ,indian e>?quake1 #bgh2 ( pr9cipal epo*s ( e>?quake-waves ( di/ant orig91 #cch ,"t-records1 g5]al inaccuracy (1 #cbd ,"t-relations ( s\nd & %ock 9 ,h]e=d e>?quake1 #bch2 9 ,inv]ness e>?quake1 #bec ,trigonometrical survey1 revis$1 ( ,khasi hills aft] ,indian e>?quake1 #cab2 int]pretation ( results1 #cad ,tw9 e>?quakes1 orig9 (1 #cb1 #hi1 #abj1 #aec1 #agd1 #bbc2 ,neapolitan e>?quake1 #ca2 ,&alusian e>?quake1 #hg2 ,*>le/on e>?quake1 #ajh2 ,rivi]a e>?quake1 #adi1 #aej2 ,h]e=d e>?quake1 #bba ,undulatory %ock1 #e ,unfelt e>?-waves1 ,&alusian e>?quake1 #hb2 ,rivi]a e>?quake1 #aeg2 ,indian e>?quake1 #bhj ,uzielli1 ,g41 #adc1 #agf ,velocity1 maximum1 ( wave-motion1 9 ,neapolitan e>?quake1 #ce2 9 ,indian e>?quake1 #bgb ,velocity ( e>?-waves1 me?ods ( det]m9+1 #ci1 #ic1 #abg1 #bbi2 v>iation ) dep?1 #ccf2 =m ( wave-pa?s1 #ccf2 velocity ( diff]5t phases1 #cci2 ( ,neapolitan e>?quake1 #ci2 ( ,&alusian e>?quake1 #ib2 ( ,*>le/on e>?quake1 #abf2 ( ,japanese e>?quakes1 #ahh2 ( ,h]e=d e>?quake1 #bbi2 ( ,indian e>?quake1 #bge1 #bgi1 #bhd ,visible e>?-waves 9 ,*>le/on e>?quake1 #aaj2 9 ,japanese e>?quake1 #ahf2 9 ,indian e>?quake1 #bfh ,volcanic e>?quakes1 #e1 #gj ,vorticose %ock1 #e ,wat]1 effect ( ,&alusian e>?quake on und]gr\nd1 #ig ,wat]falls caus$ by fault-sc>ps ( ,indian e>?quake1 #cje ,wave-pa?1 #ac ,we/1 ,c4,d41 #bgb ,woolhope anticl9al & ,h]e=d e>?quake1 connection betwe51 #bda 99 99 99 99 99 ---------------------------------------- ------------------- ,typographical errors correct$ 9 text3 ,page #ed3 ,casam5ello replac$ ) ,casam5ella ,page #aag3 ',capta9 ,dutton' replac$ ) ',major ,dutton' ,page #aai3 ',capt4 ,dutton' replac$ ) ',major ,dutton' ,page #cae3 ,rangsonobo replac$ ) ,rangsanobo ,page #ccf3 'p] sec4 p] sec4' replac$ ) 'p] sec4' ,page #ccg3 negligeable replac$ ) negligible ---------------------------------------- ------------------- 99 99 99 99 99