salah ve dig 2011

8/3/2019 Salah Ve Dig 2011

http://slidepdf.com/reader/full/salah-ve-dig-2011 1/17

This article appeared in a journal published by Elsevier. The attached

copy is furnished to the author for internal non-commercial research

and education use, including for instruction at the authors institution

and sharing with colleagues.

Other uses, including reproduction and distribution, or selling or

licensing copies, or posting to personal, institutional or third partywebsites are prohibited.

In most cases authors are permitted to post their version of the

article (e.g. in Word or Tex form) to their personal website or

institutional repository. Authors requiring further information

regarding Elsevier’s archiving and manuscript policies are

encouraged to visit:

http://www.elsevier.com/copyright



8/3/2019 Salah Ve Dig 2011


Author's personal copy

Seismic velocity and Poisson’s ratio tomography of the crust beneath East Anatolia

Mohamed K. Salah a,⇑, Sßakir Sßahin b, Ufuk Aydin c

a Geology Department, Faculty of Science, Tanta University, Tanta 31527, Egypt b Department of Geophysics, Faculty of Engineering and Architecture, Süleyman Demirel University, 32260 Isparta, Turkeyc Earthquake Research Center, Ataturk University, Yakutiye 25240, Erzurum, Turkey

a r t i c l e i n f o

Article history:

Received 25 May 2010Received in revised form 12 October 2010Accepted 31 October 2010Available online 3 December 2010

Keywords:

Crustal structureSeismic tomographySeismic wave velocityPoisson’s ratioEastern Anatolia

a b s t r a c t

Eastern Anatolia is a region in the early stages of continent–continent collision and so provides a uniqueopportunity to study the early development of continental plateau. Located within the Alpine–Himalayanfold-thrust fault belt, theAnatolian plateau is geologically very complex, with over half of the surface areacovered with late Cenozoic volcanics of diverse composition. The plateau is also seismically active and isdissected by numerous seismogenic faults predominantly of strike-slip motion. In this study, we deter-mine 3-Dtomographic images of thecrust beneatheastern Anatolia by inverting a large number of arrivaltime data of P - and S -waves. From the obtained P - and S -wave velocity models, we estimated the Pois-son’s ratio structures for a more reliable interpretation of the obtained velocity anomalies. Our tomo-graphic results are generally consistent with the major tectonic features of the region. High P - andS -wave velocity anomalies are recognized near the surface, while at deeper crustal layers, low seismicwave velocities are widely distributed. Poisson’s ratio exhibits significant structural heterogeneities com-pared to the imaged velocity structure. The seismic activity is intense along highly heterogeneous zonesand is closely associated with pre-existing faults in the central and western parts of the study area.Results of the checkerboard resolution test indicate that the imaged anomalies are reliable features downto a depth of about 40 km. The low-velocity/high Poisson’s ratio zones in the middle to lower crust areconsistent with many geophysical observations such as strong Sn attenuation, low Pn and Sn velocity,and the absence of mantle lid, implying the presence of partial melt in the uppermost mantle.

Ó 2010 Elsevier Ltd. All rights reserved.

1. Introduction

Turkey and its surrounding region are considered as an ‘excel-lent natural laboratory’ to study a variety of seismotectonic pro-cesses such as post-collisional intracontinental convergence,tectonic escape-related deformation, and the consequent struc-tures that include fold and thrust belts, suture zones, activestrike-slip faulting, active normal faulting and the associated basinformation (Kalyoncuoglu, 2007). The study of its neotectonic fea-tures and the current active tectonics are a key for the understand-ing of the entire eastern Mediterranean region (Fig. 1). Platetectonic models (DeMets et al., 1990; Jestin et al., 1994; McCluskyet al., 2000) based on analysis of global seafloor spreading, faultsystems, and earthquake slip vectors indicate that the Arabianplate is moving in a north–northeast direction relative to Eurasiaat a rate of 18–25 mm/yr, averaged over about 3 Myr. These mod-els also indicate that the African plate is moving in a northerlydirection relative to Eurasia at a rate of about 10 mm/yr. Differen-tial motion between Africa and Arabia ($10–15 mm/yr) is accom-

modated predominantly by left-lateral motion along the Dead SeaFault Zone (DSFZ). This northward motion results in continentalcollision along the Bitlis–Zagros fold and thrust belt (Fig. 1),intense earthquake activity (Fig. 2), high topography in easternTurkey and the Caucasus Mountains, and the westward extrusionof the Anatolian plate. Three major structures, thus, control the tec-tonics of Turkey; they are the dextral North Anatolian Fault Zone(NAFZ), sinistral East Anatolian Fault Zone (EAFZ) and the Ae-gean–Cyprean Arc (Fig. 1). The Anatolian wedge between the NAFZand EAFZ moves westward away from eastern Anatolia because of the collision zone between the Arabian and the Eurasian plates.Ongoing deformation along, and mutual interaction among themhave resulted in four distinct neotectonic provinces, namely, theEast Anatolian contractional, the North Anatolian, the Central Ana-tolian Ova and the West Anatolian extensional provinces (Fig. 1).Each province is characterized by its unique structural elementsand presents a typical region to study active strike-slip, normaland reverse faulting and the associated basin formation (Bozkurt,2001).

The westward extrusion of the Anatolian wedge, initiated in theearly Pliocene (e.g., Dhont et al., 1998; Kocyigit and Beyhan, 1998;

Platzman et al., 1998; Armijo et al., 1999; Barka et al., 2000), is

1367-9120/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.doi:10.1016/j.jseaes.2010.10.021

⇑

Corresponding author.E-mail address: [email protected] (M.K. Salah).

Journal of Asian Earth Sciences 40 (2011) 746–761

Contents lists available at ScienceDirect

Journal of Asian Earth Sciences

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / j s e a e s

8/3/2019 Salah Ve Dig 2011



accompanied by anticlockwise rotation (McKenzie, 1970; West-away, 1994; Seber et al., 1997; Reilinger et al., 2006), and is inter-preted as a lateral escape of the continental lithosphere away from

zones of compression (tectonic escape) to minimize topographicrelief and to avoid subduction of buoyant continental material.Whether the westward motion is driven by push forces causedby topography in eastern Turkey or by pull forces caused by sub-

duction south of the Aegean since the late Oligocene ( Jolivetet al., 1994; Jolivet and Patriat, 1999) is still a matter of controversy(Bozkurt, 2001). Earlier results of Reilinger et al. (1997), however,suggest that the westward displacement and counterclockwiserotation of Anatolia is driven both by pushing from the Arabianplate and by pulling or basal drag associated with the founderingAfrican plate along the Aegean and Cyprean arcs (Fig. 1). In general,there is an agreement that these are the boundary conditionsallowing the westward mass transfer of Anatolia, frequently con-sidered as a rigid plate bounded by the NAFZ and the EAFZ meetingat Karliova.

The eastern Mediterranean region has a remarkably long his-toric record of major earthquakes (e.g., Ambraseys, 1975; Ambra-seys and Jackson, 1998) and has been the focus of intensegeologic and geophysical investigations (e.g., Sengör et al., 1985;Spakman, 1991; Mueller and Kahle, 1993; De Jonge et al., 1994).Because of sparse seismic stations in the region, the seismic activ-ity could not be monitored well and earthquakes with magnitudes<4.0 were not accurately located. Recent observations show thatthe seismic activity in eastern Turkey is higher than previouslyobserved. The upper crust of eastern Anatolia is seismotectonically

very active, where the majority of earthquakes are shallower than20 km depths. This implies that there is no continental under-thrusting/subduction of Arabia beneath Eurasia (Türkelli et al.,2003) and that only the upper crust in Anatolia is seismogenic,which is consistent with similar results in other continentalplateaus (e.g., Maggi et al., 2000). Moreover, Türkelli et al. (2003)found that most of the seismic activity seems to occur in the uppercrust (in the first 10 km). However, the EAFZ, the Bitlis suture zone,the Karliova junction area and the area east of Karliova have somehypocenters which may originate in the lower crust (h > 20km) aswell (Fig. 2). This may suggest that the EAFZ and Bitlis suture areseismogenically thicker than the NAFZ. A continuous band of seis-micity stretches eastward from the commonly defined eastern-most extent of the NAFZ (Karliova) to Lake Van. This observation

may suggest that the NAFZ continues all the way to the main re-cent fault in northwestern Iran (Zagros Mountain). This is consis-tent with the observation of Talebian and Jackson (2002) that themain recent fault in northwestern Iran and the NAFZ combine to

Fig. 1. Simplified tectonic map of eastern Turkey showing major structures and neotectonic provinces (from Sßengör et al., 1985; Barka, 1992). DSFZ – Dead Sea Fault Zone,EAFZ – East Anatolian Fault Zone, NAFZ – North Anatolian Fault Zone, NEAFZ – Northeast Anatolian Fault Zone.

Fig. 2. Epicentral distribution of NEIC (US Geological Survey) seismicity in easternAnatolia and the surrounding regions. Circles vary in size according to magnitudeand in grey color according to the depth of the hypocenter.

M.K. Salah et al./ Journal of Asian Earth Sciences 40 (2011) 746–761 747

8/3/2019 Salah Ve Dig 2011



form a nearly continuous band of right-lateral shear on the marginof the Arabian and Eurasian plates. The area has also been affectedby several strong earthquakes (e.g., Pasinler earthquake inSeptember 13, 1924, M = 6.8; Erzincan earthquakes in December26, 1979, M = 7.9; Horasan–Narman event in October 30, 1983,

M = 6.9; and Erzincan earthquake in March, 13, 1992, M = 6.8). Inparticular the December 26, 1979 Erzincan earthquake was themost destructive event that hit the area as most of the cities withtheir residents were lost.

Although the crustal and upper mantle structure beneath east-ern Anatolia and the northern Arabian plate have been studied byseismic tomography on a regional scale (e.g., Sandvol et al., 2001;Al-Lazki et al., 2004; Lei and Zhao, 2007; Schmid et al., 2008); thereis no detailed local seismic tomography study for the region. In thepresent work, the three-dimensional velocity and Poisson’s ratiostructures of the crust and the uppermost mantle are investigatedby inverting a large number of P - and S -wave arrival times gener-ated by local earthquakes in eastern Turkey. The implications of these structures and their consistency with other geophysical

investigations, the current seismic activity and the present-daytectonics are then discussed for a more thorough understandingof the seismotectonics of Anatolia and its surrounding regions.

2. Data

In the present study, we used a total number of 7380 eventsthat occurred between latitudes 37–41°N and longitudes 38–

44.5°E in the period from January 2003 to November 2009(Fig. 3). These events are recorded by 39 seismic stations belongingto GEOFON and the Turknet (Turkish National Telemetric Earth-quke Network), which is operated by the Turkish General Director-ate of Disaster and Emergency Management. These stations

comprise 30 broadband (BB), 1 very broadband (VBB), and 8short-period seismic stations. Few stations operate with a sam-pling frequency of 50 Hz, and the remaining with 100 Hz. The dy-namic range is 140 and 164–184 dB for the broadband and theshort-period seismic stations, respectively. The crustal model of Herrin (1968) and the HYPO71 source code (Lee and Lahr, 1972)are used for the determination of the hypocentral parameters.The errors in the hypocentral locations do not exceed 2.5 km forall events. Except the northeastern and the central southern re-gions of the study area, all other parts have abundant seismicitythat is recorded by a nearly uniform seismic network. This is re-flected on the resolution scale and reliability of the obtained struc-tures as will be explained in the following sections. Earthquakesare clustered in the central, western, and southeastern regions,

and are mostly related to movements on active faults, especiallythe EAFZ and the NAFZ (Fig. 3). The 7380 events generated31,730 P and 29,320 S arrivals recorded by the 39 seismic stationsshown in Fig. 3; which imply that the ray path coverage of bothP - and S -wave data sets are almost similar (Figs. 4 and 5). Theapproximately equal number of P - and S -wave arrivals and thegood ray criss-crossing in most parts of the study area have impor-tant implications about the reliability of the obtained velocity and

Fig. 3. Epicentral distribution of the 7380 earthquakes used in this study shown as circles, which vary in color according to the focal depth (scale at the bottom). The blacktriangles show the 39 seismic stations in eastern Anatolia. Black lines denote active faults (Sßaroglu et al., 1992); NAFZ and EAFZ are the North and East Anatolian fault zones.(For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

748 M.K. Salah et al./ Journal of Asian Earth Sciences 40 (2011) 746–761

8/3/2019 Salah Ve Dig 2011



Poisson’s ratio structures (e.g., Widiyantoro et al., 1999; Gorbatovand Kennett, 2003). The accuracy of arrival times is estimated tobe lesser than 0.10 s for P -wave data and somewhat larger(<0.20 s) for the S -wave data. All residuals have been carefully

examined with respect to the assumed initial velocity model.Finally, 5- and 7-s cut-off values are set for P - and S -wave data,respectively (Fig. 6). However, more than 80% of the residuals arewithin the bounds ±2.5 s.

3. Methods

To analyze the arrival time data in eastern Anatolia, we used thetomographic method of Zhao et al. (1992, 1994) which has been

adopted for many parts of the world with different tectonic cir-cumstances (e.g., Zhao and Kanamori, 1995; Zhao et al., 1996,1997, 2001; Serrano et al., 1998, 2002a,b; Kayal et al., 2002; Salahet al., 2007). This method is adaptable to a general velocity

Fig. 4. Horizontal ray path coverage of P -wave (a) and S -wave (b) data sets. Every path between an event and a recording station is drawn as one straight line. Small opencircles and triangles denote events and recording stations, respectively.


8/3/2019 Salah Ve Dig 2011



structure which includes several complex-shaped velocity discon-tinuities and allows for 3-D velocity variations everywhere in themodel. The discontinuities represent known geological boundaries,like the Moho discontinuity and/or a subducting slab boundary,etc. A 3-D grid net is set up in the model to express the 3-D velocitystructure. Velocity perturbations at the grid nodes are taken as un-known parameters. The velocity perturbation at any point in themodel is calculated by linearly interpolating the velocity perturba-tions at the eight grid nodes surrounding that point. To calculatetravel times and ray paths accurately and rapidly, an efficient3-D ray-tracing technique (Zhao et al., 1992) is employed that iter-

atively uses the pseudo-bending technique (Um and Thurber,1987) and Snell’s law. Station elevations are taken into accountin the ray tracing scheme. The LSQR algorithm (Paige and Saunders,1982) with a damping regularization is used to solve the large andsparse system of observation equations, allowing a great numberof data to be used to solve a large tomographic problem. The non-linear tomographic problem is solved by iteratively conducting lin-ear inversions. In each iteration; perturbations to hypocentralparameters and velocity structure are determined simultaneously.A detailed description of the method is given by Zhao et al. (1992,1994) and Zhao (2001). A grid spacing of 0.4° in horizontal direc-tions is adopted for the present study. Vertically, five layers of gridnodes are set up at 4, 12, 25, 40, and 55 km depths (Fig. 7). We firsttried slightly different grid spacing and finally adoptedthe one pre-

sented in Fig. 7, to get a reasonable resolution with respect to thepresent data set (see next section).

After determining the P - and S -wave velocity models as de-scribed before, we used the relation: (Vp/Vs)2 = 2(1Àr)/(1À 2r),

to determine the elastic parameter Poisson’s ratio (r) (see Utsu,1984). By definition, Poisson’s ratio is the ratio of radial contractionto axial elongation, and is considered as a key parameter in study-ing petrologic properties of crustal rocks and can provide moreconstraints on the crustal composition than either P - or S -wavevelocity alone (Zhao et al., 2004; Salah et al., 2007). Its value incommon rock types ranges from 0.20 to 0.35 (Christensen, 1996).Poisson’s ratio has proved to be very effective for the clarificationof the seismogenic behavior of the crust, especially the role of crus-tal fluids in the nucleation and growth of earthquake rupture (e.g.,Kayal et al., 2002; Zhao et al., 2002).

Selecting the initial velocity model is an important step in anytomographic inversion since it affects the amplitude and distribu-tion of the obtained velocity anomalies. The Arabia–Eurasia colli-sion in eastern Anatolia pushed the Anatolian plate to move tothe west and created the NAFZ in eastern Turkey during the mid-to-late Miocene (Sßengör and Yılmaz, 1981; Ferrari et al., 2003).Such collision zones are usually characterized by a thick crust.Thus, Mindevalli and Mitchell (1989) modeled the crust and uppermantle velocity structure beneath eastern and western Turkeyusing single-station measurements of Rayleigh and Love surfacewave group velocities, and concluded a 40-km crustal thickness.Necioglu (1999) analyzed single-station measurements of surfacewave velocities from Iranian earthquakes recorded at stationANTO, which is located in central Turkey. He estimated a crustal

thickness of 42–44 km from events located in eastern Turkey andnorthwestern Iran. Zor et al. (2003) inverted the Eastern TurkeySeismic Experiment (ETSE) receiver functions for the crustal struc-ture beneath eastern Turkey, and reported an average crustal

Fig. 5. Ray path coverage of P -wave (a) and S -wave (b) data sets in depth direction.Small open circles and inverted grey triangles denote events and recording stations,

respectively. Other details are the same as those of Fig. 4.

(a) P-wave Residuals

-20.0

-10.0

0.0

10.0

20.0

Epicentral Distance (km)

R e s i d u a l ( s e c )

(b) S-wave Residuals

-20.0

-10.0

0.0

10.0

20.0

0 100 200 300 400 500

0 100 200 300 400 500

Epicentral Distance (km)

R e s i d u a l ( s e c )

Fig. 6. Input travel-time residuals relative to the assumed initial velocity model vs.

epicentral distance in kilometers for P -wave (a), and S -wave data sets. A 5- and 7-s-cut-off is used in the P - and S -wave tomography inversion, respectively.


8/3/2019 Salah Ve Dig 2011



thickness of 45 km and an average crustal shear-wave velocity of 3.7 km/s. Accordingly, we used the simple P -wave crustal velocitymodel of Turkelli et al. (2003) for eastern Anatolia with a Mohoat adepth of 42 km, as our initial model but with a P -wave velocity of 5.2 km/s for the top most 2-km-thick layer instead of 4.93 km/s(Table 1). This model is obtained through employing a grid searchtechnique and phase data from 66 very well-located events thatare evenly distributed throughout the Anatolian plateau (Türkelli

et al., 2003). An initial S -wave velocity model is calculated by usinga Vp/Vs ratio of 1.79 deduced from a Wadati diagram (Fig. 8) con-structed from arrival time data of 20 varying-depth events, whichare evenly distributed throughout the study region (Fig. 9). We first

checked a number of slightly different initial P -wave velocity mod-els with different Vp/Vs ratios (varying gradually from 1.70 to 1.85)and applied it to different sub-data sets and found that the overallseismic structure has no substantial variations with only slightchanges in some portions. Finally, the model shown in Table 1,along with a Vp/Vs ratio of 1.79 are selected as they give the min-imum RMS travel-time residuals.

In order to study the relation between the nucleation zones of

moderate and large earthquakes (M b or M wP 5.0) and theobtained seismic velocity and Poisson’s ratio anomalies, we col-lected 83 events that occurred in the study area since 1974 fromthe earthquake catalogs of the National Earthquake Information

Fig. 7. Configuration of grid net adopted for the present study in horizontal (a) and depth (b), directions. Grid spacing is 0.4o and 8–15 km in horizontal and depth directions,respectively. Straight lines in (a) denote the location of three vertical cross sections shown in Figs. 18–20. Black lines denote active faults; NAFZ and EAFZ are the North andEast Anatolian fault zones.


8/3/2019 Salah Ve Dig 2011



Center (NEIC), US Geological Survey (Fig. 9). A close inspection of the distribution of the epicenters of these large events implies that

they occur mainly due to movements along the NAFZ and the EAFZ.

4. Resolution and results

In order to check the reliability of the obtained velocity andPoisson’s ratio anomalies and the spatial resolution of the presentdata sets, we first conducted the checkerboard resolution test

(e.g., Inoue et al., 1990; Zhao et al., 1992). To make a checkerboard,positive and negative velocity anomalies of 3% are assigned to the3-D grid nodes as in Fig. 10. Synthetic arrival times are calculatedfor this input checkerboard model. Numbers of stations, eventsand ray paths in the synthetic data are the sameas those in the realdata. Random errors of 0.1–0.15 s similar in magnitude to those of the real data are added to the synthetic data and are then invertedwith the same algorithm used for the real data. The inverted imageof the checkerboard shows areas of good and poor resolution.Figs. 11 and 12 show the resolution of both Vp and Vs structures,respectively. The checkerboard resolution test indicates a goodand uniform resolution of about 50 km horizontally for both Vp

and Vs structures in eastern Anatolia especially at 12 and 25 kmdepths. This is because of the more uniform distribution of many

horizontal and the vertical ray paths passing at these depths.However, the edge portions at 40 km depth and the southern partof the study area at 4 km depth have a relatively poor resolutionowing to insufficient ray paths criss-crossing at these regions.

In applying the tomographic method described above to theeastern Anatolia data set (Fig. 3), we found that the sum of squaredtravel-time residuals was reduced by 50% of its initial value afterthe inversion. The final root-mean-square travel-time residualsare 0.296 s for P -wave and 0.446 s for S -wave data. The study areahas enough ray coverage at four depth layers (4, 12, 25, and 40 km)in which the number of P and S rays passing through each gridnode (hit count) is adequate to retrieve the velocity anomalies(Figs. 13 and 14). The southwestern and central parts have largehit counts and many nodes are hit by more than 6000 rays at thefirst three layers. Grid nodes with hit counts <6 are not includedin the inversion.

Table 1

Initial P -wave velocity model adopted for the

present study.

Depth (km) P -wave velocity (km/s)

0 5.20

2 6.3042 7.69

Vp/Vs = 1.79

0

10

20

30

40

0 10 20 30 40 50

Tp (sec)

T s - T p ( s e c )

Fig. 8. A cumulative Wadati diagram constructed from arrival time data of 20selected events distributed in the study area with various focal depths. Theresulting Vp/Vs ratio of 1.79 is used to derive the initial S -wave velocity model fromthe P -wave velocity model shown in Table 1.

Fig. 9. Distribution of 83 moderate and large crustal earthquakes (stars) that occurred in eastern Anatolia ( M P 5.0) since 1974 (see text for details), and the 20 events(circles) used to construct the Wadati diagram shown in Fig. 8 for an optimum Vp/Vs ratio. Stars vary in size according to magnitude; whereas all symbols vary in grey coloraccording to the focal depth. Thin black lines denote active faults in the study region; whereas the thin gray lines denote political borders. NAFZ and EAFZ are the North andEast Anatolian fault zones.


8/3/2019 Salah Ve Dig 2011



Inversion results of Vp, Vs, andr distributions at four depth lay-ers are shown, respectively, in Figs. 15–17. Figs. 18–20 show theVp, Vs, and r images along three vertical cross-sections in easternAnatolia (see Fig. 7 for the location of cross-sections). These imagesshow the velocity and Poisson’s ratio perturbations in percentage

from the initial velocity model at each depth. We have also con-ducted a number of inversions by adopting slightly different initialmodels and using different sub-data sets. It was found that theoverall pattern of the velocity and r structures as shown inFigs. 15–17, and Figs. 18–20 is stable and the change in the ampli-tude of the velocity anomalies is generally less than 1%.

Significant lateral and vertical variations of up to ±6% of velocity(Vp and Vs) and ±10% of Poisson’s ratio are revealed in the studyarea. Higher-than average velocity anomalies are revealed at4 km depth which change gradually downward to average velocityat 12 km depth and low-velocity at 25 km depth (Figs. 15 and16a–c). At 40 km depth, low-velocity zones are detected nearactive faults (Figs. 15 and 16d). The EAFZ and the NAFZ are charac-terized by intense seismicity at shallow layers and low velocity at

25 km depth. Poisson’s ratio (r

) shows high structural heterogene-ity at the different crustal layers (Fig. 17), and is generally higherthan the average at both shallow and deeper layers (4, 12, and40 km depths) which implies a general low S -wave velocity

Fig. 10. An example of the input checkerboard synthetic model for both P - and S -

wave data (see text for details). Black and white symbols denote positive andnegative synthetic velocity anomalies (±3%), respectively, which are assigned togrid nodes. Thin gray lines denote political borders.

Fig. 11. The results of the checkerboard resolution test for P -wave velocity at four crustal depths (see text for details). Black and white symbols denote high and lowvelocities, respectively. The perturbation scale is shown at the bottom. The depth of each layer is shown below each map. Thin gray lines denote political borders.


8/3/2019 Salah Ve Dig 2011



Fig. 12. The results of the checkerboard resolution test for S -wave velocity at four crustal depths. Other details are similar to those of Fig. 11.

Fig. 13. Number of rays passing through each grid node (hit count) for P -wave data at 4 depth slices. Scale is shown to the right.


8/3/2019 Salah Ve Dig 2011



Fig. 14. Number of rays passing through each grid node for S -wave data at 4 depth slices. Other details are similar to those of Fig. 13.

Fig. 15. P -wave velocity structures (in %) at depths of 4 (a), 12 (b), 25 (c), and 40 (d) km beneath eastern Anatolia. Red and blue colors denote low- and high-velocities,respectively. Numbers between brackets show the depth range of the microseismic activity plotted as crosses. Moderate and large earthquakes ( M P 5.0) occurring in thesame depth range of the background seismicity are plotted as white circles. Thin solid lines denote active faults in eastern Anatolia. The perturbation scale (±6%) is shown tothe right. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)


8/3/2019 Salah Ve Dig 2011



compared to the P -wave velocity. The r image at a depth of 25 kmis clearly lower than average; although small portions of high r

zones are also detected (Fig. 17c). The majority of the moderateand large earthquakes are closely related to the active fault zones

Fig. 16. S -wave velocity structures at the four depth slices. Other details are similar to those of Fig. 15. (For interpretation of the references to colour in thisfigure legend, thereader is referred to the web version of this article.)

Fig. 17. Distribution of Poisson’s ratio (r) structures at four depth slices. Red and blue colors denote high and low r, respectively. The perturbation scale (±10%) is shown tothe right. Other details are similar to those of Fig. 15. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this

article.)


8/3/2019 Salah Ve Dig 2011



which are characterized generally by low-velocity/high Poisson’sratio (Figs. 15–17). Microseismic activity is also intense at suchareas. Along cross sections AA’, BB’ and CC’ (Figs. 18–20); the shal-low high-velocity/high Poisson’s ratio zones are clearly visible,which change to low-velocity/low Poisson’s ratio around a depthof 25 km. The EAFZ is characterized by moderate Vp, low Vs, and

very high Poisson’s ratio (Fig. 18). This anomalous structureextends in an east–west direction consistent with the fault orien-tation, because the low-velocity/high Poisson’s ratio zone is notvisible along cross section BB’ which runs in a NNE direction. Thelocation of the Bitlis–Zagros Suture Zone (BZSZ) along cross sectionCC’, on the other hand, is associated with a heterogeneous velocityand Poisson’s ratio structures (Fig. 20). Moderate and large crustalearthquakes (shown as big white circles) occur in both low- andhigh-velocity/low to high Poisson’s ratio zones. The implicationsof these velocity and r anomalies and their relation to other geo-physical studies conducted in eastern Anatolia are briefly discussedin the following paragraphs.

5. Discussion

We determined the detailed 3-D seismic velocity and Poisson’sratio tomography fromlocal earthquake data beneath eastern Ana-

tolia. The obtained seismic wave velocity and Poisson’s ratio mod-els are generally consistent with many previous geophysicalobservations in eastern Anatolia. For example, Zor et al. (2003)and Angus et al. (2006) using S -wave receiver functions, detectedvarious crustal low-velocity zones predominantly at 25 km depth,consistent with our results at the same depth (Figs. 15 and 16c)and is corresponding with the location of geothermal and Quater-nary volcanic centers. In Fig. 18, there is an intense seismic activityat longitude 40.5°E, extending downward to a depth of 20 km. Thisseismogenic zone is very close to the EAFZ and is characterized by

average to high Vp, low Vs, and very high Poisson’s ratio; implyingthe presence of fluids ascending upward from the hot lithosphere.Although a low Vp anomaly, which may be caused by the presenceof a partially molten material, is clearly visible at 20–30 km depth,the Vs at this depth is not as much as low; and consequently, the ris not substantially high. A similar feature is also visible at crosssection CC’ (Fig. 20) from the surface downward to a depth of 17 km at a latitude of 38.25°N. The low-velocity anomalies areinterpreted as being caused by hot lithosphere resulting from thecollision between the Arabian and Eurasian plates (Kadinsky-Cadeet al., 1981; Gök et al., 2000). Previously, Rodgers et al. (1997)pointed out that inefficient Sn propagation (corresponding to highattenuation), low Pn velocity and regional volcanism may indicatepartial melt in the upper mantle. Çakir et al. (2000), by forward

modelling of the radial receiver functions, constructed 1-D crustalshear-wave velocity models that include a lower crustal low-veloc-ity zone, indicating a partial melt mechanism which may representthe source of surfacing magmatic rocks and regional volcanism

Fig. 18. Vertical cross sections of Vp, Vs and r structures along line AA’ (see Fig. 7,

for the locations of the cross sections). The red color denotes the low-velocity andhigh Poisson’s ratio, whereas high-velocity and low Poisson’s ratio are shown inblue. Large white circles and crosses show, respectively, the location of moderate-large earthquakes (M P 5.0) and the microseismic activity in a 40 km wide-zonearound the profile. The perturbation scale (±6% for velocity and ±10% for Poisson’sratio) is shown to the right. Inverted solid triangle on the top denotesthe location of the EAFZ. (For interpretation of the references to colour in this figure legend, thereader is referred to the web version of this article.)

Fig. 19. Vertical cross sections of Vp, Vs and r structures along line BB’. Inverted

solid triangles on the top denote the location of the EAFZ and the NAFZ. All otherdetails are similar to those of Fig. 18. (For interpretation of the references to colourin this figure legend, the reader is referred to the web version of this article.)


8/3/2019 Salah Ve Dig 2011



(see also Sandvol et al., 1998). Using surface wave measurementsfrom earthquakes occurring in the present study area and recordedat Isparta station in SW Turkey; Erduran et al. (2007) detected ra-pid velocity gradients at depths between 0 and 10 km and between25 and 45 km. The low-velocity zone in the mid-crust occurs stron-ger at depths between 13 and 25 km. They also predicted a crustalthickness of $41 km for the region and a general decrease of shearwave velocities down in the crust and uppermost part of the man-tle. Our results (Figs. 15, 16 and 18–20) are generally consistent

with the above mentioned low-velocity zones.Although theresolutionof thepresentresults is notgood enough

below a depth of 40 km, but there is an indication that the mappedlow-velocity zones in the middle–lower crust might extend down-ward to the uppermost mantle (Fig. 19). This is consistent withthe anomalously low upper mantle shear wave velocities (slightlylower than 4.5 km/s) downto 130 km depth beneath central Turkeythat were mapped by Meier et al. (2004). In addition, Maggi andPriestly (2005), using surface waveform tomography to elucidatethe upper mantle shear-wave velocity structure beneath theTurkey–Iranian plateau and adjacent regions, obtained a lowshear-wave velocity anomaly in the uppermost mantle beneathTurkey and the Aegean Sea. They showed that the strongest portionof the low-velocity anomaly is located under the easternmost

Turkish plateau and extended down to 200 km depth.Higher Pn velocities (>8 km/s) imply a tectonically stable man-

tle lid, while very low Pn velocities (<7.8 km/s) are usually an indi-

cation of the existence of partial melt in the uppermost mantle(e.g., Hearn, 1999; Calvert et al., 2000). Al-Lazki et al. (2004)detected broad scale ($500 km) zones of low Pn velocity anomaliesbeneath the Anatolian plate, the Anatolian plateau, the Caucasusregion, northwestern Iran and northwestern Arabia. These low-

velocity regions are interpreted to be hot and unstable mantle lidzones and may be associated with the latest stage of intense volca-nism that has been active since the late Miocene and the subduc-tion of Tethyan oceanic lithosphere beneath Eurasia. Gök et al.(2007) observed very low shear wave velocities at the crustal por-tion (30–38 km) of the northeastern part of the Anatolian plateauindicating the lack of a lithospheric mantle underneath the plateauand its replacement with asthenospheric materials. Isotopic andrare earth elements data analyzed by Adiyaman and Chorowicz(2002) indicate deep mantle sources for this volcanism. Spectralinterpretation of magnetic anomaly data obtained by Bektasßet al. (2007), shows that the magnetic thickness (crustal thicknessderived from magnetic data) of the region is shallow and variesfrom 13 to 23 km, implying that the temperatures are high within

the crust in most locations. The anomalously high temperatures inthe crust are also reflected in the high temperatures of hot springs(>45 °C) and in the young ages of volcanics in the region. Lei andZhao (2007) and Schmid et al. (2008) detected extensive low-velocity anomalies beneath eastern Turkey which are consistentwith many other geophysical investigations in the region such aslow Pn and Sn velocity and strong Sn attenuation. A high heat flowis also observed in the region (Tezcan, 1995). These observationssuggest that the uppermost mantle is partially molten and theasthenosphere is close to the base of the crust, consistent withthe existence of the volcanism in the region. The volcanism in east-ern Turkey has been active since the Late Miocene, which may beascribed in part to the subducted Tethyan oceanic lithosphere be-neath Eurasia (Al-Lazki et al., 2003, 2004).

Luccio and Pasyanos (2007) detected high S -wave velocity inthe upper crust of the eastern Mediterranean including a signifi-cant part of the present study area and a thin low-velocity sedi-ment zone near the surface. The later, however, could not bedetected by the present study. The lower crust and upper mantlein the eastern Mediterranean are also characterized by lowS -wave velocity. The anomalously low-velocities found in theupper mantle are interpreted to be an indication of serpentinizedmantle, as has been suggested also in other subduction zones (seeHyndman and Peacock, 2003, and references therein). This proba-bly relates to a hydrous or hydrothermal alteration as suggestedin other convergent zones, where small percentage of serpentinein the crust would produce water in the mantle by the subductingcrust (Hyndman and Peacock, 2003). The physical properties of the forearc mantle are affected by the presence of hydrous miner-

als as serpentine, which, if present, can decrease the seismic wavevelocity and raise the Poisson’s ratio (Hyndman and Peacock,2003). Luccio and Pasyanos (2007) speculate that the uppermostmantle should be composed of partially serpentinized peridotite,with a certain amount of serpentine due to the fact that in someregions the observed S -wave velocities are around or below4.3 km/s. This hypothesis is also supported by the low-velocitiesassociated with the lower crust in the same region (Figs. 15 and16) since the seismic properties of the uppermost mantle arerelated to the type of the overlying lower crust. Partial meltingin the upper mantle could explain the high heat flow observedin the eastern Mediterranean, where serpentinization plays animportant role (Ben-Avraham et al., 2002 and references therein;Kearey and Vine, 2004). Although different processes such as par-

tial melting, water content, compositional or phase change, hightemperature, can lower the seismic velocity (as in the Hellenic–Cyprian trench), either serpentinization or partial melting could

Fig. 20. Vertical cross sections of Vp, Vs and r structures along line CC’. Invertedsolid triangle on the top denotes the location of the Bitlis–Zagros Suture Zone(BZSZ). All other details are similar to those of Fig. 18. (For interpretation of thereferences to colour in this figure legend, the readeris referred to the webversion of this article.)


8/3/2019 Salah Ve Dig 2011



be favorite candidates to explain the observed low S -wave veloc-ities beneath eastern Anatolia.

Many studieshave concluded that Lg propagationin the Turkish–Iranian Plateau is usually blocked or highly attenuated (Kadinsky-Cade et al., 1981; Mitchell et al., 1997; Rodgers et al., 1997; Cong

and Mitchell, 1998; Sandvol et al., 2001; Al-Damegh et al., 2004).Zor et al. (2007) detected verylow Lg Q 0-values beneaththe easternAnatolian plateau andwesternTurkeyaround the Menderes Massif.High Lg -attenuation values withintheAnatolian plateau(Q 0$100–200) may be caused by a combination of scattering and intrinsicattenuation. Scatteringattenuation is dueto thetectonic complexityandthe intrinsic attenuation could be dueto thewidespread crustalmelting. However, the lowest Q 0-values in the eastern Anatolianplateau ($70–100) are most probably due to the widespreadQuaternary volcanism; although the high degree of distributeddeformation in eastern Anatolia (e.g., Reilinger et al., 1997) couldcontribute to these low Q 0-values. Receiver function waveforminversion in eastern Turkey has suggested that there is no rapidchange in thecrustalthickness across theBitlis Sutureand theEAFZ;

acandidatethatmayreduceorblockLg propagation.Consistentwithour low-velocity zones at the lower crust (Figs. 15 and 16), they alsoobserved localized mid-crustal low-velocity zones scatteredthroughout the eastern Anatolian plateau (Zor et al., 2007). Theselow-velocity zones might be an indication of partial melt withinthe eastern Turkey crust (see also Zor et al., 2003). This inference isalsosupportedby thewidespread, young(less than 6 Ma)volcanismin theregion(e.g., Keskin,2003)andlow Pn velocities (Hearn andNi,1994; Al-Lazki et al., 2004) coupled with high Sn attenuation (Göket al., 2003; Al-Damegh et al., 2004) as an indication of anomalouslyhot lithosphere. Another region where low Lg Q 0-values have beenfound to coincide with low crustal velocity is central and southernTibet. Xie et al. (2004) observed low Lg Q 0-values of $100 in centralTibet and extremely low Lg Q 0-values of $60–70 in southern Tibet.Similar mid-crustal, low-velocity zones have also been found inthe southern Tibetan crust.

6. Conclusions

The 3-D velocity and Poisson’s ratio structures beneath easternAnatolia is estimated by inverting a large number of P - and S -wavearrival times generated from local earthquakes, which are recordedat a relatively dense and uniformly distributed seismic network.Results of the checkerboard resolution test, hit count maps, andthe ray path coverage indicate that the obtained structures are reli-able features down to a depth of about 40 km. The following con-clusions can be drawn from the obtained results:

1. The shallow velocity structure is dominated by higher-than-

average seismic wave velocities, which change downward tolower velocity at the middle–lower crustal depths.

2. High Poisson’s ratio zones are clearly visible at most crustal lay-ers down to a depth of 40 km, which are consistent with thepossibility of the existence of partial melt in the lower crustand the uppermost mantle.

3. Both large and small earthquakes are closely associated withlow-velocity/high Poisson’s ratio zones and are intense nearactive faults in the region.

4. The mapped low-velocity/high Poisson’s ratio zones in the mid-dle–lower crust are consistent with many geophysical evi-dences such as low Pn and Sn velocity, high Sn attenuation,high heat flow, shallow magnetic thickness, and low Lg Q 0-values. These observations are analogous to other continental

plateaus such as the Tibet and are interpreted to be an indica-tion of a serpentinized hot mantle that is partially molten.The presence of this partial melt in the uppermost mantle feedsthe widespread Cenozoic volcanism in the region.

Acknowledgements

The authors thank Ugur Topatan, Didem Soyuer, and Caner Dur-mus for their assistance in data preparation. Seismicity and largeearthquakes information is obtained from earthquake catalogs

reported by the National Earthquake Information Center (NEIC),(http://neic.usgs.gov/neis/epic/ ). Comments of Editor-in-Chief Bor-ming Jahn and two anonymous reviewers significantly im-proved the manuscript. Most figures in this paper are made usingGMT (Generic Mapping Tools) software written by Wessel andSmith (1998).

References

Adiyaman, Ö., Chorowicz, J., 2002. Late Cenozoic tectonics and volcanism in thenorthwestern corner of the Arabian plate: a consequence of the strike-slipDeadSea fault zone and the lateral escape of Anatolia. Journal of Volcanology andGeothermal Research 117, 327–345.

Al-Damegh, K., Sandvol, E., Al-Lazki, A., Barazangi, M., 2004. Regional seismic wavepropagation (Lg and Sn) and Pn attenuation in the Arabian Plate and

surrounding regions. Geophysical Journal International 157, 775–795.Al-Lazki, A., Seber, D., Sandvol, E., Turkelli, N., Mohamad, R., Barazangi, M., 2003.

Tomographic Pn velocity and anisotropy structure beneath the Anatolianplateau (eastern Turkey) and surrounding regions. Geophysical Research Letters30. doi:10.1029/-2003GL017391.

Al-Lazki,A.I., Sandvol, E., Seber, D., Barazangi, M., Turkelli, N., Mohamad,R., 2004. Pntomographic imaging of mantle lid velocity and anisotropy at the junction of the Arabian, Eurasian and African plates. Geophysical Journal International 158,1024–1040. doi:10.1111/j.1365-246X.2004.02355x.

Ambraseys, N.N., 1975. Studies in historical seismicity and tectonics. In:Geodynamics Today. Royal Society, London, pp. 7–16.

Ambraseys, N.N., Jackson, J.A., 1998. Faulting associated with historical and recentearthquakes in the eastern Mediterranean region. Geophysical JournalInternational 133, 390–406.

Angus, D.A., Wilson, D.C., Sandvol, E., Ni, J.F., 2006. Lithospheric structure of theArabian and Eurasian collision zone in eastern Turkey from S-wave receiverfunctions. Geophysical Journal International 166, 1335–1346. doi:10.1111/

j.1365-246X.2006.03070.x.Armijo, R., Meyer, B., Huber, A., Barka, A., 1999. Westward propagation of the North

Anatolian fault into the northern Aegean: timing and kinematics. Geology 27,267–270.

Barka, A.A., 1992. The north Anatolian fault zone. Annals of Tectonics 6, 164–195.Barka, A., Akkyüz, H.S., Cohen, H.A., Watchorn, F., 2000. Tectonic evolution of the

Niksar and Tasova-Erbaa pull-apart basins, North Anatolian Fault Zone: theirsignificance for the motion of the Anatolian block. Tectonophysics 322, 243–264.

Bektasß, Ö., Ravat, D., Büyüksaraç, A., Bilim, F., Atesß, A., 2007. Regional geothermalcharacterizationof east Anatolia fromaeromagnetic, heat flowand gravity data.Pure and Applied Geophysics 164, 975–998. doi:10.1007/s00024-007-0196-5.

Ben-Avraham, Z., Ginzburg, A., Makris, J., Eppelbaum, L., 2002. Crustal structure of the Levant Basin, eastern Mediterranean. Tectonophysics 346, 23–43.

Bozkurt, E., 2001. Neotectonics of Turkey– a synthesis. Geodynamica Acta 14, 3–30.Çakir, Ö., Erduran, M., Çınar, H., Yılmaztürk, A., 2000. Forward modeling receiver

functions for crustal structure beneath station TBZ (Trabzon, Turkey).Geophysical Journal International 140, 341–356.

Calvert, A., Sandvol, E., Seber, D., Barazangi, M., Roecker, S., Mourabit, T., Vidal, F.,Alguacil, G., Jabour, N., 2000. Geodynamic evolution of the lithosphere and

upper mantle beneath the Alboran region of the western Mediterranean:constraints from travel time tomography. Journal of Geophysical Research 105(10), 10, 871–10,898.

Christensen, N.I., 1996. Poisson’s ratio and crustal seismology. Journal of Geophysical Research 101, 3139–3156.

Cong, L., Mitchell, B., 1998. Lg coda Q and its relation to the geology and tectonics of the Middle East. Pure and Applied Geophysics 153, 563–585.

De Jonge, M., Wortel, M., Spakman, W., 1994. Regional scale tectonic evolution andthe seismic velocity structure of the lithosphere and upper mantle. Journal of Geophysical Research 99, 12091–12108.

DeMets, C., Gordon, R.G., Argus, D.F., Stein, S., 1990. Current plate motions.Geophysical Journal International 101, 425–478.

Dhont, D., Chorowicz, J., Köse, O., Yürür, T., 1998. Poly-phased block tectonics alongthe North Anatolian Fault in the Tosya basin area (Turkey). Tectonophysics 299,213–227.

Erduran, M., Çakır, Ö., Tezel, T., Sßahin, Sß., Alptekin, Ö., 2007. Anatolian surface waveevaluated at GEOFON station ISP Isparta, Turkey. Tectonophysics 434, 39–54.

Ferrari, A., King, G., Manighetti, I., Armijo, R., Meyer, B., Tapponier, B., 2003. Long-term elasticity in the continental lithosphere; modelling the Aden ridge

propagation and the Anatolian extrusion process. Geophysical JournalInternational 153, 111–132.

Gök, R., Pasyanos, M.E., Zor, E., 2007. Lithospheric structure of the continent–continent collision zone: eastern Turkey. Geophysical Journal International 169,1079–1088. doi:10.1111/j.1365-246X.2006.03288.x.


8/3/2019 Salah Ve Dig 2011



Gök, R., Sandvol, E., Turkelli, N., Seber, D., Barazangi, M., 2003. Sn attenuation in theAnatolian and Iranian plateau and surrounding regions. Geophysical ResearchLetters 30 (2003). doi:10.1029/2003GL018020.

Gök, R., Türkelli, N., Sandvol, E., Sßeber, D., Barazangi, M., 2000. Regional wavepropagation in Turkey and surrounding regions. Geophysical Research Letters27, 429–432.

Gorbatov, A., Kennett, B.L.N., 2003. Joint bulk-sound and shear tomography for

western Pacificsubduction zones. Earth andPlanetaryScience Letters 210, 527–543.

Hearn, T.M., 1999. Uppermost mantle velocities and anisotropy beneath Europe. Journal Geophysical Research 104, 15123–15139.

Hearn, T.M., Ni, J., 1994. Pn velocities beneath continental collision zones: theTurkish–Iranian Plateau. Geophysical Journal International 117, 273–283.

Herrin, E., 1968. Seismological tables for P -phases. Bulletin of the SeismologicalSociety of America 60, 461–489.

Hyndman, R.D., Peacock, S.M., 2003. Serpentinization of the forearc mantle. EarthPlanetary Science Letters 212, 417–432.

Inoue, H., Fukao, Y., Tanabe, K., Ogata, Y., 1990. Whole mantle P-wave travel timetomography. Physics of the Earth and Planeteary Interiors 59, 294–328.

Jestin, F., Huchon, P., Gaulier, J.M., 1994. The Somalia plate and the East African riftsystem: present-day kinematics. Geophysical Journal International 116,637–654.

Jolivet, L., Daniel, J.M., Truffert, C., Goffe, B., 1994. Exhumation of deep crustalmetamorphic rocks and crustal extension in back-arc regions. Lithos 33, 3–30.

Jolivet, L., Patriat, M., 1999. Ductile extension and the formation of the Aegean Sea.In: Durand, B., Jolivet, L., Horvath, F., Seranne, M. (Eds), The Mediterranean

Basins: Tertiary Extension within the Alpine Orogen. Geological Society of London, Special Publication, 156, pp. 427–456.Kadinsky-Cade, K., Barazangi, M., Oliver, J., Isacks, B., 1981. Lateral variations of

high-frequency seismic wave propagation at regional distances across theTurkish and Iranian Plateaus. Journal of Geophysical Research 86, 9377–9396.

Kalyoncuoglu, U.Y., 2007. Evaluationof seismicity andseismic hazardparameters inTurkey and surrounding area using a new approach to the Gutenberg–Richterrelation. Journal of Seismology 11, 131–148. doi:10.1007/s10950-006-9041-.

Kayal, J.R., Zhao, D., Mishra, O.P., De,R., Singh, O.P., 2002. The2001 Bhuj earthquake:tomographic evidence for fluids at the hypocenter and its implications forrupture nucleation. Geophysical Research Letters 29 (24), 2152. doi:10.1029/2002GL015177.

Kearey, P., Vine, F.J., 2004. Global Tectonics, second ed. Blackwell Science, Oxford.Keskin, M., 2003. Magma generation by slap steepening and break-off beneath a

subduction-accretion complex: an alternative model for collision-relatedvolcanism in eastern Anatolia, Turkey. Geophysical Research Letters 30 (24),8046. doi:10.1029/2003GL018019.

Kocyigit, A., Beyhan, A., 1998. A new intercontinental transcurrent structure: theCentral Anatolian Fault Zone, Turkey. Tectonophysics 284, 317–336.

Lee, W.H.K., Lahr, J.C., 1972. HYP071: a computer program for determininghypocenter, magnitude, and first motion pattern of local earthquakes. OpenFile Report, US Geological Survey, 100 pp.

Lei, J., Zhao, D., 2007. Teleseismic evidence for a break-off subducting slab undereastern Turkey. Earth and Planetary Science Letters 257, 14–28. doi:10.1016/

j.epsl.2007.02.011.Luccio, F.D., Pasyanos, M.E., 2007. Crustal and upper mantle structure in the eastern

Mediterranean from the analysis of surface wave dispersion curves.Geophysical Journal International 169, 1139–1152. doi:10.1111/j.1365-246X.2007.03332.x.

Maggi, A., Jackson, J.A., Priestley, K., Baker, C., 2000. A re-assessment of focal depthdistributions in southern Iran, Tien Shan and northern India: do earthquakesreally occur in the continental mantle? Geophysical Journal International 143,629–661.

Maggi, A., Priestly, K., 2005. Surface waveform tomography of the Turkish–Iranianplateau. Geophysical Journal International 160, 1068–1080.

McClusky, S., Balassanian, S., Barka, A., Demir, C., Ergintav, S., Georgiev, I., Gurkan,O., Hamburger, M., Hurst, K., Kahle, H., Kastens, K., Kekelidze, G., King, R.,Kotzev, V., Lenk, O., Mahmoud, S., Mishin, A., Nadariya, M., Ouzounis, A.,

Paradissis, D., Peter, Y., Prilepin, M., Reilinger, R., Sanli, I., Seeger, H., Tealeb, A.,Toksöz, M.N., Veis, G., 2000. Global positioning system constrains on platekinematicsand dynamics in the eastern Mediterraneanand Caucasus. Journal of Geophysical Research 105, 5695–5719.

McKenzie, D.P., 1970. Plate tectonics of the Mediterranean region. Nature 220, 239–343.

Meier, T., Dietrich, K., Stöckhert, B., Harjes, H.P., 2004. One-dimensional models of shear wave velocity for the eastern Mediterranean obtained from the inversionof Rayleigh wave phase velocities and tectonic implications. Geophysical

Journal International 156, 45–58.Mindevalli, Ö.Y., Mitchell, B.J., 1989. Crustal structure and possible anisotropy in

Turkeyfrom seismic surface wave dispersion. Geophysical Journal International98, 93–106.

Mitchell, B.J., Pan, Y., Xie, J., Cong, L., 1997. Lg coda Q variation across Eurasia anditsrelation to crustal evolution. Journal of Geophysical Research 102, 22767–22779.

Mueller, S., Kahle, H.-G., 1993. Crust-mantle evolution, structures and dynamics of the Mediterranean–Alpine region. In: Smith, D.E., Turcotte, D.L. (Eds.),

Contributions of Space Geodesy to Geodynamics: Crustal Dynamics,Geodynamics Series, vol. 23. AGU, Washington, DC, pp. 249–298.Necioglu, A., 1999. Determination of crustal and upper mantle structure between

Iran and Turkey from the dispersion of Rayleigh waves. Journal of the BalkanGeophysical Society 2, 139–150.

Paige, C.C., Saunders, M.A., 1982. LSQR: sparse linear equations and least squaresproblems. ACM Transactions on Mathematical Software 8, 43–71.

Platzman, E.S., Tapirdamaz, C., Sanver, M., 1998. Neogene anticlockwise rotation of central Anatolia (Turkey): preliminary palaeomagnetic and geochronologicalresult. Tectonophysics 299, 175–189.

Reilinger et al., 2006. GPS constraints on continental deformation in the Africa-Arabia-Eurasia continental collision zone and implications for the dynamics of

plate interactions. Journal of Geophysical Research 111, B05411. doi:10.1029/2005JB004051.

Reilinger, R.E., McClusky, S.C., Oral, M.B., King, R.W., Toksoz, M.N., Barka, A.A., Kinik,I., Lenk, O., Sanli, I., 1997. Global positioning system measurements of present-day crustal movements in the Arabia–Africa–Eurasia plate collision zone.

Journal of Geophysical Research 102, 9983–9999.Rodgers, A.J., Ni, J.F., Hearn, T.M., 1997. Propagation characteristics of short-period

Sn and Lg in the Middle East. Bulletin of the Seismological Society of America87, 396–413.

Salah, M.K., Sahin, S., Destici, C., 2007. Seismic velocity and Poisson’s ratiotomography of the crust beneath southwest Anatolia: an insight into theoccurrence of large earthquakes. Journal of Seismology 11, 415–432.doi:10.1007/s10950-007-9062-2.

Sandvol, E., Al-Damegh, K., Calvert, A., Seber, D., Barazangi, M., Mohamad,R., Gök, R.,Türkelli, N., Gürbüz, C., 2001. Tomographic imaging of Lg and Sn propagation inthe Middle East. Pure and Applied Geophysics 158, 1121–1163.

Sandvol, E., Seber, D., Calvert, A., Barazangi, M., 1998. Grid search modeling of receiver functions: Implications for crustal structure in the Middle East and

North Africa. Journal of Geophysical Research 103, 26899–26917.Sßaroglu, F., Emre, Ö., Kusßçu, _I., 1992. Map of Active Faults in Turkey. GeneralDirectorate of Turkish Mineral Research and Exploration Institute, Ankara,Turkey.

Schmid, C., van der Lee, S., VanDecar, J.C., Engdahl, E.R., Giardini, D., 2008. Three-dimensional S velocity of the mantle in the Africa-Eurasia plate boundaryregion from phase arrival times and regional waveforms. Journal of GeophysicalResearch 113, B03306. doi:10.1029/2005JB004193.

Seber, D., Vallve, M., Sandvol, E., Steer, D., Barazangi, M., 1997. Middle Easttectonics: applications of Geographic Information Systems (GIS). GSA Today 7,1–6.

Sßengör, A.M.C., Yılmaz, Y., 1981. Tethyan evolution of Turkey: a plate tectonicapproach. Tectonophysics 75, 181–241.

Sßengör, A.M.C., Görür, N., Saroglu, F., 1985. Strike-slip faulting and related basinformation in zones of tectonic escape: Turkey as a case study. In: Biddle, K.T.,Christie-Blick, N. (Eds), Strike-Slip Deformation, Basin Formation andSedimentation. Soc. Econ. Paloeontol. Mineral. Spec. Publ., 37, pp. 227–264.

Serrano, I., Bohoyo, F., Galindo-Zaldívar, J., Morales, J., Zhao, D., 2002a. Geophysicalsignatures of a basic-body rock placed in the upper crust of the External Zones

of the Betic Cordillera (Southern Spain). Geophysical Research Letters 29 (11).doi:10.1029/ 2001GL013487.

Serrano, I., Morales, J., Zhao, D., Torcal, F., Vidal, F., 1998. P-wave tomographicimages in the central Betics–Alborán sea (South Spain) using local earthquakes:contribution for a continental collision. Geophysical Research Letters 25 (21),4031–4034. doi:10.1029/ 1998GL900021.

Serrano, I., Zhao, D., Morale, J., 2002b. 3-D crustal structure of the extensionalGranada basin in the convergent boundary between the Eurasia and Africanplates. Tectonophysics 344, 61–79.

Spakman, W., 1991. Delay time tomography of the upper mantle beneath centralEurope, the Mediterranean, and Asia Minor. Geophysical Journal International107, 309–332.

Talebian, M., Jackson, J., 2002. Offset on the main recent fault of NW Iran andimplications for the lateCenozoic tectonics of the Arabia–Eurasia collision zone.Geophysical Journal International 150, 422–439.

Tezcan, A., 1995. Geothermal explorations and heat flow in Turkey. In: Gupta, M.L.,Yamamo, M. (Eds.), Terrestrial Heat Flow and Geothermal Energy in Asia.Oxford and IBH Publishing Co. Pvt. Ltd., New Delhi, pp. 23–42.

Türkelli, N., Sandvol, E., Zor, E., Gok, R., Bekler, T., Al-Lazki, A., Karabulut, H., Kuleli,

S., Eken, T., Gurbuz, C., Bayraktutan, S., Seber, D., Barazangi, M., 2003.Seismogenic zones in eastern Turkey. Geophysical Research Letters 30 (24),8039. doi:10.1029/ 2003GL018023.

Um, J., Thurber, C., 1987. A fast algorithm for two-point seismic ray tracing. Bulletinof the Seismological Society of America 77, 972–986.

Utsu, T., 1984. Estimation of parameters for recurrence models of earthquakes.Bulletin of the Earthquake Research Institute, University of Tokyo 59, 53–66.

Wessel, P., Smith, W.H.F., 1998. New improved version of generic mapping toolsreleased. EOS Transactions American Geophysical Union 79, 579.

Westaway, R., 1994. Present-day kinematics of the Middle East and EasternMediterranean. Journal of Geophysical Research 99, 12071–12090.

Widiyantoro, S., Kennett, B.L.N., van der Hilst, R.D., 1999. Seismic tomography withP- and S-data reveals lateral variations in the rigidity of deep slabs. Earth andPlanetary Science Letters 173, 91–100.

Xie, J.K., Gök, R., Ni,J., Aoki, Y., 2004. Lateral variations of crustal seismic attenuationalong the INDEPTH profiles in Tibet from Lg Q inversion. Journal of GeophysicalResearch 109, B10308. doi:10.1029/2004JB002988.

Zhao, D., 2001. New advances of seismic tomography and its applications to

subduction zones and earthquake fault zones: a review. The Island Arc 10, 68–84.Zhao, D., Hasegawa, A., Horiuchi, S., 1992. Tomographic imaging of P- and S-wave

velocity structure beneath northeastern Japan. Journal of Geophysical Research97, 19909–19928.


8/3/2019 Salah Ve Dig 2011



Zhao, D., Hasegawa,A., Kanamori, H., 1994. Deep structure of Japan subductionzoneas derived from local, regional and teleseismic events. Journal of GeophysicalResearch 99, 22313–22329.

Zhao, D., Kanamori, H., 1995. The 1994 Northridge earthquake: 3-D crustalstructure in the rupture zone and its relation to the aftershock locations andmechanisms. Geophysical Research Letters 22, 763–766.

Zhao, D., Kanamori, H., Humphreys, E., 1996. Simultaneous inversion of local and

teleseismic data for the crust and mantle structure of southern California.Physics of the Earth and Planetary Interiors 93, 191–214.

Zhao, D., Mishra, O.P., Sanda, R., 2002. Influence of fluids and magma onearthquakes: seismological evidence. Physics of the Earth and PlanetaryInteriors 132, 249–267.

Zhao, D., Tani, H., Mishra, O.P., 2004. Crustal heterogeneity in the 2000 westernTottori earthquake region: effect of fluids from slab dehydration. Physics of theEarth and Planetary Interiors 145, 161–177.

Zhao, D., Wang, K., Rogers, G., Peacock, S., 2001. Tomographic image of low P-velocity anomalies above slab in northern Cascadia subduction zone. Earth,Planets and Space 53, 285–293.

Zhao, D., Xu,Y., Wiens, D., Dorman, L., Hildebrand, J., Webb, S., 1997. Depth extent of the Lau back-arc spreading center and its relation to subduction processes.Science 278, 254–257.

Zor, E., Sandvol, E., Gürbüz, C., Türkelli, N., Seber, D., Barazangi, M., 2003. The crustal

structure of the east Anatolian plateau (Turkey) from receiver functions.Geophysical Research Letters 30, 8044. doi:10.1029/2003GL018192.

Zor, E., Sandvol, E., Xie, J., Türkelli, N., Mitchell, B., Gasanov, A.H., Yetirmishli, G.,2007. Crustal attenuation within the Turkish Plateau and surrounding regions.Bulletin of the Seismological Society of America 97, 151–161. doi:10.1785/0120050227.


salah ve dig 2011

Documents