18Mar2005 19:32 AR AR233-EA33-02.tex AR233-EA33-02.sgm LaTeX2e(2002/01/18) P1:IKH 10.1146/annurev.earth.32.101802.120415 Annu.Rev.EarthPlanet.Sci.2005.33:37–112 doi:10.1146/annurev.earth.32.101802.120415 Copyright(cid:1)c 2005byAnnualReviews.Allrightsreserved FirstpublishedonlineasaReviewinAdvanceonJuly16,2004 THE NORTH ANATOLIAN FAULT: A New Look A.M.C. S¸engo¨r,1,3 Okan Tu¨ysu¨z,1,3 Caner I˙mren,2 Mehmet Sakınc¸,1 Haluk Eyidog˘an,2 Naci Go¨ru¨r,1,3 Xavier Le Pichon,4 and Claude Rangin4 g 1I˙stanbulTeknikU¨niversitesi,AvrasyaYerBilimleriEnstitu¨su¨,Ayazag˘a34469,I˙stanbul, or s. Turkey;email:[email protected],[email protected],[email protected],[email protected] w alrevieonly. I2˙sI˙statannbbuul,lTTuekrkneiky;U¨enmivaeilr:sictaensie,[email protected],¨letyeisdi,oJgeaonfi@ziiktuB.eo¨dlu¨um.tru¨,Ayazag˘a34469, w.annual use I3˙sI˙statannbbuul,lTTuekrkneikyU¨niversitesi,MadenFaku¨ltesi,JeolojiBo¨lu¨mu¨,Ayazag˘a34469, won 4Colle`gedeFrance—ChairedeGe´odynamique,Europoˆledel’Arbois,BatimentLae¨nnec, m wpers hallD,e´tage2BP80—13545Aix-en-Provence,France;email:[email protected], oaded fro9/13. For [email protected] wnl1/0 KeyWords strike-slipfaulting,shearzonedevelopment,earthquakefaulting, Don 0 theSeaofMarmara,tectonicsofTurkey 2. y o 1g 7-1olo Dedicated to the memory of three pioneers, I˙hsan Ketin, Sırrı Erinc¸ and Melih 3n 5.33:Tech Tmoyksateyr,iaensdofatrheecNenotrsthtuAdennatt,oAliyaknuFtaBualrtk.a,whoburnthimselfoutinpursuitofthe 00of Earth Planet. Sci. 2California Institute fist■onauugbitlAdstruiznbgcooshtnrtitotre-hlnata.-hctTaetachrtcaefrloTNerkhtmAieeoiFenrNdofmogobreryatmnhtpeeAirrndioangalnarpttoeooprslrtsiihoaitvsexnerisnmFosatuaTruttauhelitrlnyka(Nlne1oydA3caoFmtoll)idoz1iesas1trtlaiMyao1nnaa2dli0aons0gnta-iogfkgfimenaernn-tlhceoioernnanetgletaliyrdsnfteewaaxncentetrsadatljelpubrsrxlaotytrsapiewkpameogi-dsaesietnlnenitgdps- v. y westward.ItreachedtheSeaofMarmaranoearlierthan200kaago,althoughshear- eb R relateddeformationinabroadzonetherehadalreadycommencedinthelateMiocene. nu. Thefaultzonehasaverydistinctmorphologicalexpressionandisseismicallyactive. n A Sincetheseventeenthcentury,ithasshowncyclicalseismicbehavior,withcentury- long cycles beginning in the east and progressing westward. For earlier times, the recordislessclearbutdoesindicatealivelyseismicity.Thetwentiethcenturyrecord hasbeensuccessfullyinterpretedintermsofaCoulombfailuremodel,wherebyevery earthquake concentrates the shear stress at the western tips of the broken segments leadingtowestwardmigrationoflargeearthquakes.TheAugust17andNovember12, 1999,eventshaveloadedtheMarmarasegmentofthefault,mappedsincethe1999 earthquakes, and a major, M ≤ 7.6 event is expected in the next half century with anapproximately50%probabilityonthissegment.Currently,thestrainintheSeaof Marmararegionishighlyasymmetric,withgreaterstraintothesouthoftheNorthern Strand.Thisisconditionedbythegeology,anditisbelievedthatthisisgenerallythe casefortheentireNorthAnatolianFaultZone.Whatisnowneededisamoredetailed 0084-6597/05/0519-0037$20.00 37 18Mar2005 19:32 AR AR233-EA33-02.tex AR233-EA33-02.sgm LaTeX2e(2002/01/18) P1:IKH 38 S¸ENGO¨RETAL. geologicalmappingbasewithdetailedpaleontologyandmagneticstratigraphyinthe shear-related basins and more paleomagnetic observations to establish shear-related rotations. INTRODUCTION TheNorthAnatolianFault(NAF)[Figures1(seecolorinsert)and2]isoneofthe largestcurrentlyactivestrike-slipfaultsintheworld,formingthemostprominent partofamedium-sizestrike-slip-dominatedbeltofdeformation,i.e.,akeirogen g or (Ketin1948,S¸engo¨r1979a;forkeirogen,seeS¸engo¨r&Natal’in1996,p.639,note s. w 8),innorthernTurkey.ItextendsfromtheGulfofSarosinthenorthernAegean e ww.annualrevional use only. Spdetaiesaratala.ltnlo1ec9lteih9noe1gf,tOsor¨oowzumengreheo1lnfy02K0t0ha0ker2mlıs,ooYtvouaitlthm(h3eear9znc◦o1eBat8sla(cid:3)aNtl,c.,ck2o40Sn10n◦e20ae)1cwst(cid:3)Eihniot)ghrienttshhEeeaanAEsdaetesgktreneAaenTnpuaitnatrogkplehiayaronffgaoheirirngl1yh(2Tp0rael0yagmtukelmaaauzr, m wpers (S¸arog˘lu1985,Koc¸yig˘itetal.2001,S¸engo¨retal.2003).Thedextralshearasso- oaded fro9/13. For ccbieyanttSe¸rdeanlwgmio¨tarhin1thl9ae7n9NdaAG),Fraecneodcneetiavnseunaetsubaarolclaryodslissnhtkehsaerunzpoornwtheiet(hrtnetrAhmeeegdHeaethnlle,encGricoresscsueiabsndnuSocrhtteihoaenrrnZzaoonnndee Downln 01/0 (Dewey & S¸engo¨r 1979, McKenzie and Jackson 1983, Le Pichon et al. 1993). 2. y o Although the NAF has been subject to numerous geological, geomorphological, 11og andgeophysical(especiallyseismological)investigationssinceitsrecognitionas 37-nol a major strike-slip fault in 1948 by ˙Ihsan Ketin (Ketin 1948; see previous re- 5.33:Tech viewsandsynthesesbyKetin1957,1969,1976;Pavoni1961;Allen1969,1982; 00of Ambraseys 1969; S¸engo¨r 1979a; Barka 1981, 1992; S¸engo¨r & Canıtez 1982; Earth Planet. Sci. 2California Institute S1s2(¸2i90en0n70c0g30e3o)a¨,)t,rh]n2,eea0tatci0naoa2ldnt.;aa1Nssl9teoar8eonv2pdee;hsmiKpincbetieercearrianatrz1latli2htyi1,qot9u1nh9a9ae3kl9r;ei9insactl(heosAlrofyekAssydteuuo¨cegzcotuunhesmcetteefa1ronnl7.lti,len2od1g0w90bti9h0in9le,ginf[2asgB0yuua0mlatr2lkhp)aba.ososS1iol9iuiknt9mec9bre:a;yAltBlhEynaemoernxknr,paeyalmeeovttdoaaaeuslldst.. ev. by amountofgeological,geophysical,andgeotechnicaldatahavebeengatheredin R u. theSeaofMarmara[wheretheprobabilityofrupturebyalargeearthquakewithin n n thenext50yearsishigh(Parsonsetal.2000,Kingetal.2001,Atakanetal.2002; A alsoseeFigure13(seecolorinsert)lastframe]andaroundit(Karaca&Ural1999, Barkaetal.2000b,Dog˘an&Kurter2000,Yaudetal.2000,Ansal2001,Taymaz 2001, Aksu & Yaltırak 2002, Go¨ru¨r et al. 2002, Tokso¨z 2002, Altunel & Akyu¨z 2003, Anonymous 2003a; also see the Rangin et al. 2001 atlas and Go¨ru¨r 2002, 2003),fillingapreviouslyexistinggapinourknowledgeofthecourseandcharacter oftheNAFinitswesternpartbecauseofitssubmarinelocation.Theamount,diver- sity,quality,andthedensityofdatacollectedinafewyearsareunparalleledinthe historyofgeologicalinvestigationsinTurkeyanddonothavemanycounterpartsin theworld.ThisgreataccelerationofactivityinandaroundtheSeaofMarmaraalso hastriggeredotherstudiesalongthefault.Manyoldproblemshavebeenlookedat 18Mar2005 19:32 AR AR233-EA33-02.tex AR233-EA33-02.sgm LaTeX2e(2002/01/18) P1:IKH THENORTHANATOLIANFAULT 39 myenzs wnloaded from www.annualreviews.org1/09/13. For personal use only. thismaphaveformedinrelationtotheNAK.Notallofthearepotentialearthquakegenerators.FaulttracesdelineatedbhestructureknownastheNorthAnatolianFault(NAF).Notcretionarycomplexes(seealsoFigure4).Thefaultshavebee(1989),Eyido˘gan(1991),Barka(1993),Dirik(1993),Yilma2003),S¸enel(2002),andourownobservations.Forthesource Annu. Rev. Earth Planet. Sci. 2005.33:37-112. Doby California Institute of Technology on 0 Figure2TheNorthAnatolianKeirogen(NAK).Allthefaultsshowninarenowactive,butallhavebeenactivesometimeinthepast11Ma.MostheavierlinesrepresentthemostactivepartsofthekeirogenconstitutingtthatthekeirogenisentirelyconfinedtotheareaunderlainbyTethysideaccompiledchieflyfromT¨uys¨uz(1985),S¸aro˘gluetal.(1987,1992),Bing¨oletal.(1997a),Aky¨uzetal.(2000),Barkaetal.(2000a,b),Herece&Akay(concerningtheTethysideaccretionarycomplexes,seeFigure4. 18Mar2005 19:32 AR AR233-EA33-02.tex AR233-EA33-02.sgm LaTeX2e(2002/01/18) P1:IKH 40 S¸ENGO¨RETAL. fromdifferentviewpointsusingdifferentmethodsandnewtechnologies(theresults ofthesenewstudieshavebeenreported,inadditiontoscatteredpapersininterna- tionalliterature,someofwhicharecitedbelow,inthefollowingworkshopreports: Tataretal.2000,Altuneletal.2001,Anonymous2001,2003b,Go¨ktenetal.2001, Emreetal.2002;alsoseethefollowingcompendium:Altunel&Akyu¨z2003). UnlikepreviouscatastrophicearthquakesinTurkey,thelocationoftheAugust 17andNovember12,1999,eventsinadenselypopulatedregionofthecountry, where much of the Turkish industry is located, has led to unprecedented public interestintheNAF(e.g.,C¸orlu1999;alsoseeAtakanetal.2002).Thefactthat thecityof˙Istanbul(population≈15million),aninternationalcenteroftradeand g or culture from time immemorial, is now under serious large earthquake threat in s. w theforeseeablefuture(e.g.,Durukaletal.2002,Erdiketal.2003)hasaddedan e w.annualrevial use only. Psehae´rornoceuksssteiin2nl0tae0rr1gn)ea.trNieogeniwaolniddsiewmaisedonensnieothdnetthtoreigtihngeteerprnfuuabntliicoctniioannltseocrfeiebsntigt(iefie.acgr.at,hnDqdueplauikb&elsicPfoie´nrrtooeutrhseeesrt1(l9aer.9gg9.e,, won Papadopoulos 2002). All of this international scientific activity and public con- m wpers cern inevitably generated a vast and multifarious literature in a very short time. oaded fro9/13. For Ta(ssheeteotphtuherepfoorleslceoewonfitntNghiAcsoFrmelvpiiteeenwradtiiuasrietnotahpdardetisitemionmntateondtiihanteterlloiytdeuprcarettiucorenedectoditetthdhaebte1lli9ote9wr9a:tMeuareretr,hic¸aqsu1a9wk9ee5lsl, Downln 01/0 Bozkurt2001)intheformofanewtectonicsynthesisoftheentireNAFandasso- 2. y o ciatedstructures.Notallaspectsoftheworkundertakeninvariousearthscience 11og disciplinesbynumerousgroupscanbereviewedwithequalweightinthespacewe 7-ol 3n haveatourdisposalhere.Ouremphasisisonthegeologicalandseismicaspects 5.33:Tech of the fault and on its western part around the Sea of Marmara, where most of 00of the new information has been gathered. We have also tried to cite many of the Earth Planet. Sci. 2California Institute leeesfsfcosarpwt.eeliln-tceirrncuatliaotendalTautrteknisthiosno,ulrecaedsi,nagsttohemyuccohntwaianstveaolufatbimleedaatnadthdautpcliocmatmioonnolyf ev. by DISCOVERYOFANDHISTORYOFINVESTIGATIONS R u. ALONGTHENORTHANATOLIANFAULT n n A In the middle of the nineteenth century, the presence of a roughly 100-km-wide band of seismicity paralleling the course of the NAF already had been recog- nized (Mallet 1862, map D). This zone of seismicity was later associated with theboundarythatKober(1914,plate14;1921,figure26)drewinthefirstquar- ter of the twentieth century between his Anatolian Zwischengebirge (=median massif or betwixt mountains) and the allegedly north-vergent flank of the Alpi- des.Thefirstpieceofgeologicalfielddataconcerningtheexistenceofanactual faultzonewithinMallet’snorthernAnatolianseismicbandandcorrespondingto partofKober’sboundary(whichhehadcalledaNarbe=scar)wascollectedby Ernst Nowack (1928), who mapped a 20-km-long mylonite zone paralleling the 18Mar2005 19:32 AR AR233-EA33-02.tex AR233-EA33-02.sgm LaTeX2e(2002/01/18) P1:IKH THENORTHANATOLIANFAULT 41 Uluc¸ay(nowSog˘anlıC¸ayı)westofC¸erkes¸(40◦49(cid:3)N,32◦54(cid:3)E).In1932,Nowack pointedoutthatthismylonitezoneextendedfromthetipoftheGulfof˙Izmitto Koc¸hisar (present-day Ilgaz: 40◦55(cid:3)N, 33◦38(cid:3)E) for 250 km (Nowack 1932). He interpretedthisshearzoneastheboundarybetweenSuess’(1901)Ponticarcsand theDinarides.In1936,WilhelmSalomon-CalviinterpretedNowack’sshearzone in terms of the continental drift theory of Alfred Wegener as the eastern contin- uation of the Tonale Line of the Alps, which he believed formed a suture zone (hisSynaphie)betweentheLaurasianandGondwanianelementsinthestructure ofAnatolia.Salomon-Calvi(1936)believedthatthiszonecouldbefollowedeast- ward into Iran. In the night of December 26/27, 1939, at 0200 hours local time, g or adisastrousearthquakeofMs = 7.8–7.9(seeEyidog˘anetal.1991,Barka1996) s. w alongthisnorthAnatolianzoneoffaultingclaimedthelivesofsome40,000peo- e w.annualrevial use only. p1sol9en40i1n;9aP4n0adm).aiTrroh&uisnKgdreetthaientec1ai9tryt4h0oq,fu1aE9kr4ez1irn;ecsSauanlltoe(3md9oi◦nn4-d5Ce(cid:3)Ntaal,ivl3ie9d1◦93g40e0o(cid:3)Ealo);g(SiAcieakblyeiornlgv1e19s9t4i4g00a;;tLiToeniulslcohotsf- won the fault around Erzincan (Stchepinsky 1940, Stchepinsky et al. 1940, Pare´jas m wpers etal.1942;forlaterstudies,seeBarka1996).The1939Erzincanquakewasfol- oaded fro9/13. For liC¸onewr1ke9de4s¸,2iinn(Mr1a9sp4id=4s(uM7c.c1se);s=siino7nL.,3aˆ;bdysikeaeisnFeir1gie9us4re3of3(M)d,isswahs=tircoh7u.sl3ee)d;artaotnhdqfuuirantkhBeesroislnutu,NdGiiekessrea(drf-oeEr,rarbenafda- Downln 01/0 erences,seeKetin1948,Eyidog˘anetal.1991,andBarka1996).In1944,Necdet 2. y o Egeran and Erwin Lahn emphasized that earthquake activity between 1939 and 11og 1944hadmigratedwestwardinnorthernTurkeyalongthestructurethatSalomon- 7-ol 3n CalvihadearliercalledtheeastwardcontinuationoftheTonaleLine.Inthe1940s, 5.33:Tech interpretationsoftheseismicstructureweremadeintermsofthethenprevailing 00of tectonictheories.Acommondenominatorofalltheseinterpretationswasthatthe Earth Planet. Sci. 2California Institute stotPhotrarenomuigczaietasrunst1riiooec9cn4iwb”a4eataplest,rdbosi;neceEeeawnsrgtshehai(rsqcSahuanaanl“1koci9emnr4satoe7twong).g-reCaerlenapilvcva”iiret1fwoa9euf4dl0tthsaae;hsP“atoadhrreeo´bjgelaagessnuetintcdatseolta.rft1uho9crt4tmuh2rr;eao”BseslopufaomrAftenaonnafthttoeahlxleiap1“,i9rca4irnn5adg-; ev. by Acompletelydifferentinterpretationwasofferedby˙IhsanKetinin1948that R u. revolutionized the understanding of the structure. He noted that during all ma- n n jorearthquakesinnorthernTurkeysince1939,thesurfacebreakalwayshadthe A character of a generally east-west-striking, right-lateral fault. The vertical com- ponent of the motion always upthrew the southern block. Ketin combined these observationswiththepreviouslyknowncoursesofvariousyoung,steep,geomor- phologicallydistinctandseismicallyactiveshearzonesalongthenorthAnatolian earthquake belt and declared that the seismic zone in northern Turkey was the productofamajor,active,right-lateral,strike-slipfault.Thiswasthefirstdocu- mentationoftheexistenceofalargeandactivestrike-slipfaultintheworld[the San Andreas was not confirmed to be a strike-slip fault until 1953, by Hill & Diblee (1953), despite many earlier suggestions, including Wegener’s (1915)]. Ketin further pointed out that because interior Anatolia south of the fault was 18Mar2005 19:32 AR AR233-EA33-02.tex AR233-EA33-02.sgm LaTeX2e(2002/01/18) P1:IKH 42 S¸ENGO¨RETAL. ns aa ch Erzinfigure00). 27,1939,44).Theetal.(20 er26/n(19Aky¨uz bh mad Downloaded from www.annualreviews.orgn 01/09/13. For personal use only. AnatolianFault(NAF)sincetheDeceocks,firstemphasizedbyEgeran&LBarka(1996),Barkaetal.(2000a),an Annu. Rev. Earth Planet. Sci. 2005.33:37-112. by California Institute of Technology o ndrelatedfaultdisplacementsalongtheNortharkableeast-to-westmigrationofthemajorsh˘gluetal.(1987,1992),Eyido˘ganetal.(1991), amo quakesthereomS¸ar Earthe.Notepiledfr 3akm requco uhn Figeartbee 18Mar2005 19:32 AR AR233-EA33-02.tex AR233-EA33-02.sgm LaTeX2e(2002/01/18) P1:IKH THENORTHANATOLIANFAULT 43 largely aseismic, a whole Anatolian block had to be moving westward with respecttotheBlackSeaalongthestrike-slipfaultthathedefined.Ketinarguedthat toaccommodatesuchamovement,another,however,left-lateral,faulthadtoexist tothesouthoftheAnatolianblock(unlessthewholeofAfricawasalsomoving). HispredictionwasvindicatedaquarterofacenturylaterwhentheEastAnatolian Faultwasdiscovered(Arpat&S¸arog˘lu1972,Seymen&Aydin1972).S¸engo¨r& McKenzie (1997) noted that Ketin’s 1948 paper was one of the most important harbingersofthemodern,post-platetectonicsstudiesofcontinentaldeformation (seealsoS¸engo¨r1996). In1948,KetinstoppedthestructureshortoftheSeaofMarmara,butpointedout g or in1953,asaresultoffieldworkwithFranzRo¨sliontheYenice-Go¨nenearthquake ws. [epicenter40◦01(cid:3)N,27◦29(cid:3)E(Ketin&Ro¨sli1953)],thatthefaultcontinuedsouth e w.annualrevial use only. oowffhtBihcuehrSsisae,aaUcotlufuaMbllayatrt(mhAeaprcoaolytrhroernocttu;ogirnhthasoosgmerraeipeshsoyou;frAcyenosouannnygdmbooansuissno1sm,9f7eo7rrmgoiaivdnegssittghhneesdn“eaUpmrleeusaosbfiaotthn,”es won lakeasUlubat,butthenameofthevillageasUluabat,whichcreatesconfusion), m wpers andManyas. oaded fro9/13. For MTraoIrunmg1ha9r)a4in3th,tahNteaunrroeiyrlteohceParitnneapdrainratlaroenfaetdhayestsh-ewaade,skstuntgorewgnendstsienindgctlehartahgteetrhstuerrotvhuergyehse(odtfheHeepN.Msoo.rStfh.tShM.eSaSerlmeaˆanaoriakf 2. Downly on 01/0 (oSfp˙Iiznmdlietrweitthalt.h1e89tr6a)c,ehoafdtbheeen19f1o2rmeeadrthbqyuaakseinfgaluelftaounlttthheatGceolnibnoelcute(dGtahlelipGoullif) 11og Peninsula (Mihailovic¸ 1923, 1927). Pinar’s (1943) suggestion was not followed 7-ol 3n becauseherevidencewasequivocalandshehadnotindicatedwhatkindofafault 5.33:Tech thestructureshesuggestedwas.Ayearlater,Pfannenstiel(1944)suggestedthatthe 00of northerntroughoftheSeaofMarmaraformedbyagroupofadjacentrhomboidal Earth Planet. Sci. 2California Institute enMothxofaatretttrhhnmaesnAaio“renAana,aas”ettlgo-pwelb.iaaae5nsns8itnt-)sess,ect.iwrtsiEomkhngiiinicecchgrazzrhnoioafnnt(de1e,p9”crh4ooo(7bnEw)atgiebnpevluoryeaeirnun,dtn“e1idodn9ent4roola7aut,ytrhepettdhh.uMea6ct5naet)ordh.mretsIhacncreaarrl1aneT9t,o”t6rrgo8oteuh,ungegKihchceh(tofi“aafnfruotalhpcstesrsteoe´Sorpidefosaetstiheocldeasf ev. by Marmara, echoing Pfannenstiel (1944) and Egeran (1947). This suggestion was R u. followedbyMcKenzie(1972),whodepictedtheSeaofMarmaraasoneoftheeast- n n west-strikingextensionalstructurescharacterizingwesternTurkeyandindicated A thatextensionacrossitwasoblique(northeast-southwest).Thiswasdisputedby Dewey&S¸engo¨r(1979)andS¸engo¨r(1979a)becauseGanosDag˘(formerlyTekfur Dag˘ı,nowIs¸ıklarDag˘ı:40◦44(cid:3)N,27◦10(cid:3)E;elevation924mabovesealevel)justto thenorthofthetraceofthe1912strike-slipearthquakefault(Ambraseys&Finkel 1987,Altınoketal.2003)appearedtothemasashorteningstructureaboveathrust faultthattheyinterpretedtobethrustinga1200mdeeptoitsimmediateeastinthe SeaofMarmara,indicatingdextralstrike-slipwithintheSeaofMarmara.S¸engo¨r etal.(1985)drewadottedlinebetweentheGulfof˙Izmitandthe1912earthquake fault,emphasizingthelackofevidenceofthenatureofthestructureofthefloor of the Sea of Marmara. The large number of subsequent attempts to delineate 18Mar2005 19:32 AR AR233-EA33-02.tex AR233-EA33-02.sgm LaTeX2e(2002/01/18) P1:IKH 44 S¸ENGO¨RETAL. thenatureoftheNAFundertheSeaofMarmaragenerallyfollowedMcKenzie’s notionthatmotionacrossitwasstronglyobliqueandthatthepatternofactivefaults hadtoreflecttheoutlinesofthelozenge-shapedbathymetricbasinsunderlyingthe deepernortherntroughoftheSeaofMarmara(e.g.,Barka&Kadinsky-Cade1988, Wong et al. 1995, Barka 1997, Parke et al. 1999, Aksu et al. 2000, Ambraseys 2002a). The age of the NAF has long been thought to be Neogene, since Egeran & Lahn(1944)andKetin(1948)showedthatitdisruptedtheorogenicstructureof Turkey,theyoungestmembersofwhichclearlyreachedintotheearlyMiocenein thenorthernpartofthecountry(S¸engo¨r&Yilmaz1981).In1957,Ketinwrote, g or “Thus,themovementofthefaulthasoccurredaftertheorogeny....Itrepresents s. w a continuous sliding process with a waxing and waning intensity, which began e w.annualrevial use only. dIvneurrhyiinsygo1tu9hn6eg9Nssetyornugtcehtneuesrie(s,1,i5Kn–e2mt0ianMneymapapaghrotas)sioaznnedldywtohhfaitQcthuhiaestemsrtnailialnraytchtairgvoeeu”.gI(hnK-gheotiisinnlga1s9fta5su7yl,tnptw.h5aes2si)as. won oftheNAF,Ketin(1976)pointedoutthatwithinthe“rift”troughofthefault,the m wpers oldestsedimentaryrocksweremedialMioceneinageandthatthefaulttherefore oaded fro9/13. For htiavdeAtolotfhfbsoeeutogafhlotohnfagftseathtgseehNaatAdthFbeeheoanlddmelosatnp.gperdemduairninegdiunndkivniodwuanlleaargrtehlqyubaekceasu,stheefocurmmuulcah- Downln 01/0 of its course the fault parallels the dominant strike of the older tectonic units 2. y o it cuts. In 1961, Pavoni estimated its offset to be between 300 and 400 km, 11og but this was based on an erroneous correlation between the Cretaceous-Eocene 7-ol 3n eastern Pontide volcanic cover with the dominantly Mio-Pliocene volcanics of 5.33:Tech the Galatean Massif northwest of Ankara on the basis of the then already se- 00of riously outdated 1:800,000 geological map of Turkey (Egeran & Lahn 1942– Earth Planet. Sci. 2California Institute 1t8lAhi95cka4ata±t6yit)oh.(ne52Itn0okwo0fmr3atth)shb,eey˙IthrhAntsehatNlenbaeNesSosAeot-yTfFemesth(ttehiSemnye,Gayaanmteedoseoolunocftgut1toyrh9ere7aow5lfc)seut.thsmuTtedhuoeNilfnsaottEhirovratfzehsiKnorAecefnmfatsianneatt,oihnwloaieadfhdnotbhueFeenesatnftiualalbuotthllfitfbessy(herseeteHdcefeoeinSrnr¸etesc1pnoe9ugm7bo&¨5e-r ev. by 1979a;Hubert-Ferrarietal.2002;andthediscussioninWestaway&Arger2001, R u. appendix). n n The rise of plate tectonics shed new light on Turkish geology. In one of the A earliest papers considering the NAF in some detail from the viewpoint of plate tectonics,Atamanetal.(1975)arguedthattheTethyansuturesinnorthernTurkey had been a major factor in localizing the fault, but this was disputed by S¸engo¨r &Canıtez(1982)becausetheneo-TethyansutureimpliedbyAtamanetal.does noteverywherefollowthefault.S¸engo¨randhiscoworkershavesummarizedand synthesizedtheworkontheNAFundertakeninthelightofplatetectonicsinthe 1970s and the early 1980s in a series of publications (S¸engo¨r 1979a; S¸engo¨r & Canıtez1982;S¸engo¨retal.1982,1983,1985)inwhichtheyshowedthatthefault wasindeedmedialtolateMioceneinageandthatitsoffsetappearedtobesome- wherebetween50to100km.S¸engo¨r&Canıtez(1982)favoredan80to100km 18Mar2005 19:32 AR AR233-EA33-02.tex AR233-EA33-02.sgm LaTeX2e(2002/01/18) P1:IKH THENORTHANATOLIANFAULT 45 offsetintheeastthatpossiblydecreasedtosome30kminthewest.S¸engo¨randhis coworkersalsounderlinedtheimportanceofthebasinsalongtheNAFandwithin theAnatolianScholle(seeDewey&S¸engo¨r1979)foranunderstandingoftheage andnatureofthefault(e.g.,S¸engo¨retal.1985). ThetimebetweenS¸engo¨r’sfirstsynthesisin1979andthe1999earthquakeswas markedbyanincreasedactivityofgeologicaland,toalesserextent,geophysical workalongtheNAF.Muchofthatworkhasbuiltthefoundationonwhichthepost- 1999workwasundertakenandisdiscussedinthepresentreviewinconjunction withit. g or s. THENORTHANATOLIANFAULTANDTHENORTH w e alrevionly. ANNOARTTOHLAIANNATSOHLEIAARNZKOENIREO:EGLEENMENTSOFTHE nnuuse w.aal won FromFigure2,itisseenclearlythatthefaultsassociatedwiththeNorthAnatolian m wpers Keirogen(NAK)constituteanentireshearzoneconfinedtotheNorthAnatolian oaded fro9/13. For Triseevotihneylwys,iadwmeeaeccmaclbrleettrhi,oiasnlsbahreyeitactrhozemomnpeloestxhteepsrNooomfrlitanhteeAnsttnPmataeolmelioabzneorSi,choetfoathreiZasroslnyheeTa(erNrztAioaSnreyZ.)aT.gTheeh.eNInNAtAhSiZFs Downln 01/0 andtheNAFareelementsoftheNAK. 2. y o There are long offshoots that take off from the main trunk of the NAF and 11og veer toward interior Anatolia. The easternmost of these offshoots is the Ovacik 7-ol 3n Fault(Westaway&Arger2001;OFinFigure2),whichexploitsinpartthesuture 5.33:Tech betweentheMunzurandtheMalatyadigitationsoftheKirsehirBlock(Figures2 00of and4).AnothermajoroffshootistheSungurluFault(SFinFigure2),whichleaves Earth Planet. Sci. 2California Institute tbTcphoerheonmepdmpoSolasuefeixnndteghbsuebrryaDalnuneKdclFhoicdac¸euoeyaletitrsgs˘itiibsntouo&fattalRsreoByensetoceayfordhntihatythnaeeeiKn((K1e4idz90iir9◦lsei28enr3)mht(cid:3)iibNrareek,Mltyw3(Fa7ewsi◦egsi2nitu0fhr.t(cid:3)ieEhnTe5)wt,haOoiennvddoTaitceechintaekhtdreysadssnpiwbddlaiyetyththashicenehcSrtalheevutteentieogibrnnueDanrerle)ynur. ev. by Faults,althoughwearenotcertainthattheyareoffshootsoftheNAForwhether R u. theyevenformcoherentstructures.Inanyevent,nomajorseismicityisassociated n n withthem. A Ingeneral,theNASZbecomeswiderfromeasttowest.AroundErzincanand some150to200kmwestofit,thezoneisextremelynarrow,hardlywiderthan 10 km, although near Karliova it seems to widen again (Herece & Akay 2003, appendix 13). It becomes more than 100 km wide within the Tokat lobe of the Tethyside accretionary complexes (Figure 4), but the southern members of the shearzonehereseemtohavebeenabandonedveryearlyinitshistory.Although the whole lobe area is still seismically active (Figure 5), the main seismicity is concentratedinitsnorthernpart. FromtheIlgazLobe(ILinFigure4)westward,theshearzonebroadenscon- tinuouslyandreachesitsmaximumwidthintheMarmaraLobe(Figure4). 18Mar2005 19:32 AR AR233-EA33-02.tex AR233-EA33-02.sgm LaTeX2e(2002/01/18) P1:IKH 46 S¸ENGO¨RETAL. Annu. Rev. Earth Planet. Sci. 2005.33:37-112. Downloaded from www.annualreviews.orgby California Institute of Technology on 01/09/13. For personal use only. Figure4TheTethysideaccretionarycomplexesofnorthernandeasternTurkey.CompiledfromS¸eng¨oretal.(1980,1984),S¸eng¨or&Natal’in(1996),Yılmazetal.(1997b),Okay&T¨uys¨uz(1999,andreferencestherein),S¸eng¨oretal.(2003),andourownunpublishedobservations.AListheAnkaraLobe,IListheIlgazLobe,andtheEAACistheEastAnatolianAccretionaryComplex.AllpartsoftheTethysideaccretionarycomplexesinnorthernTurkeyhavesectorsofCimmeride(i.e.,Paleo-Tethyan)andAlpide(i.e.,Neo-Tethyan)subduction-accretioncomplexesinplacesseparatedbyremnantsoftheCimmerianContinentandinothersbroughtintocontactbyAlpidedeformationsthatelidedtheCimmerianContinentfrombetweentheCimmerideandAlpideaccretionaryprisms.MunzurandMalatyadigitationsbelongtotheMenderes-TaurusBlockasfirstdefinedbyS¸eng¨oretal.(1982).IstanbulisaHercynianfragment,withaCadomianbasementandaTriassicandCretaceous-TertiarycoverredeformedbyAlpideevents;MendereshasaPan-Africanbasement,someCimmeridemagmatismtoitsnorth,andastrongCretaceoustoEocenesouth-vergentimbrication,followedbyOligocenetopresentextension;EasternPontideshaveaPan-AfricanbasementwithastrongCimmerideimprintonwhichaCretaceousandEocenetoearlyOligocenearcwasbuiltandredeformedduringtheEocenetoMioceneconvergence.SomedeformationtoitsnorthpersistedintotheQuaternary.Kir¸sehirhasaPan-Africanbasementwithsomeolderfragments.Ithasamid-CretaceousarcbuiltacrossitandwasdeformedinthelateCretaceoustoMiocenetimes.