the north anatolian fault: a new look

81 Pages·2013·2.04 MB·English

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
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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
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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.