Zabci, Cengiz; Sançar, Taylan; Tikhomirov, Dmitry; Ivy-Ochs, Susan; Vockenhuber, Christof; Friedrich, Anke M.; Yazici, Müge; Akçar, Naki

The active tectonics of Anatolia is mostly characterized by its westward motion with respect to Eurasia between the Hellenic subduction in the west and Arabia-Eurasia continental collision in the east. Although most of the deformation is suggested to be confined along Anatolia’s boundary elements, viz. the North and East Anatolian shear zones, recent studies indicate a higher magnitude of internal strain accumulation, especially along the parallel/subparallel strike-slip faults of its central province. We present the first morphochronology-based slip rate estimate for one of these strike-slip structures, the Ovacık Fault, by using cosmogenic36Cl dating of offset fluvial deposits. At the Köseler Site (39.3643°N, 39.1688°E), two faulted risers, bounding the alluvial fan with its subplanar surface (NF1/NF1’) and the inset terrace tread (NF1/T2), are offset 19–24 and 15–22 m, respectively. The scattered surface ages and variability of 36 Cl concentrations in depth profiles suggest strong evidence for inheritance in alluvial fan and terrace deposits; thus, we used modelled depth-profile ages for both surfaces. The modelled ages 8–10 ka for NF1 and 6–8 ka for T2 yield slip-rate estimates 2.4 +0.5/–0.4 mm/a and 2.8 +0.7/–0.7 mm/a, respectively, for the upper-tread reconstruction of the NF1/NF1’and the lower-tread reconstruction of the NF1/T2. Our results together with previous slip-rate estimates for other structures show a significant internal deformation for Anatolia, especially along its subparallel strike-slip faults. These secondary faults slice Anatolia into several pieces giving rise to the formation of the Malatya-Erzincan, Cappadocian, and Central Anatolian slices, where the geometry is strongly controlled by the distribution of the Tethyan accretionary complexes.

AtıfScopus3·OpenAlex3·TR Dizin1

İncele

Yazici, Muge; Zabci, Cengiz; Natal'in, Boris A.; Sançar, Taylan; Akyuz, H. Serdar

The Ovacik Fault (OF) is one of the internal structures of the Anatolian Block, located close to its eastern boundary. Although it shows a very clear surface trace, there are no instrumentally recorded surface rupturing earthquakes on this fault. This study concludes results of the first palaeoseismological trench study on the OF with the evidence for three surface rupturing earthquakes for the last 6 kyr. Structural, stratigraphical and geochronological constraints show that the oldest event happened between 4700 and 3022 BCE, whereas the penultimate event was between 2262 and 1643 BCE. The youngest event happened after 56 BCE, which we could only delimit from below because of the absence of any dateable material from the upper layers of the relevant horizons. The derived mean interevent time of these three palaeoevents is 2400 +/- 765 years. We could not correlate any of these palaeoevents with historical earthquakes due to the absence of records in catalogues for the region of interest. Moreover, we used cumulative offsets of the major drainages to calculate the long-term slip rate of 2.7 mm/year since the Pliocene, which exceeds slip rates of other internal faults of Anatolia almost by the factor of two. Our results do not only show significant deformation for the internal parts of Anatolia but also point out a seismic potential of the OF.

AtıfWoS5·OpenAlex5

İncele

Sançar, Taylan; Zabci, Cengiz; Karabacak, Volkan; Yazici, Muge; Akyüz, H. Serdar

The sinistral Malatya-Ovack Fault Zone (MOFZ) is one of the outstanding intraplate deformation belts within Anatolia. The 165-km-long, NE-SW-striking Malatya Fault (MF), which constitutes the southern section of the MOFZ, is separated into five segments according to its surface geometry. These segments have evident morphotectonic features that reflect long- and short-term fault activity, such as morphologic structures offset by as little as 7m and as much as 7.3km. This study provides results from the first paleoseismological investigations on the MF. We find that the last earthquake occurred between 965 and 549 BCE and calculate a recurrence interval of 2275 +/- 605years from evidence for four paleo-events over the last 10ka. Considering fault segmentation and our paleoseismological data, we propose that the accumulated strain on the MF may cause a destructive earthquake (M=7.4) in the near future. Our results support the hypotheses that the MF and other NW-striking dextral and NE-striking sinistral strike-slip faults within the eastern part of Anatolia are plate boundary-related, active deformational structures.

AtıfWoS19·OpenAlex29

İncele

Yazici, Muge; Zabci, Cengiz; Sançar, Taylan; Natalin, Boris A.

Although the westward extrusion of the Anatolian Block is mainly compensated along its boundary faults, the North Anatolian and the East Anatolian shear zones, it is internally deformed in a dominant manner by some strike-slip faults as well. To obtain a better understanding about this intraplate deformation of the Anatolian Block, we investigate the tectonic geomorphology of the Ovaak Fault (OF), which is the northeastern member of the Malatya-Ovaak Fault Zone (MOFZ). Further, we apply the most common geomorphic indices, such as the hypsometric curve and integral, longitudinal channel profiles, channel steepness and concavity, mountain front sinuosity, and valley height-width ratio to characterise and quantify the deformation along the OF and the surrounding region where the regional morphology is shaped with the joint effect of palaeo- and neotectonics and other morphological factors such as palaeoglacial processes. The highest hypsometric integral, steepness and concavity values are generally observed along the northeastern strand of the OF (the Munzur Mountains) and the Kemaliye Region. Further, we interpret that high HI and steepness values indicate a regional tectonic uplift because of either a change in fault geometry, which gives rise to the vertical component on the OF, or a regional high convergence zone. Furthermore, this study gives the first calculation of vertical uplift in the northern margin of the Ovacik Basin (OB) as at least 0.5 mm/y for long term deformation history. Thus, our results exhibit that the OF is one of the intraplate strike-slip faults of the Anatolian Block. (C) 2018 Elsevier B.V. All rights reserved.

AtıfWoS20·OpenAlex22

İncele

Sançar, Taylan; Akyüz, H. Serdar; Schreurs, Guido; Zabci, Cengiz

AtıfOpenAlex10

İncele

Karabacak, Volkan; Akçar, Naki; Akyüz, Hüsnü Serdar; Önal, Ayten Öztüfekçi; Zabci, Cengiz; Sançar, Taylan

Avrasya Levhası?na göre, Afrika ve Arabistan Levhaları?nın kuzeye ve Anadolu Bloku?nun batıya doğru olan hareketi Doğu Akdeniz?in karmaşık tektonik yapısının anlaşılmasında anahtar role sahiptir. Anadolu?nun batıya kaçışında ana deformasyon zonları Kuzey ve Doğu Anadolu Fay Zonları (KAFZ ve DAFZ) ile bu sırada Anadolu içerisinde meydana gelen önemli kıta içi deformasyonlar ise KB doğrultulu sağ yanal ve KD doğrultulu sol yanal doğrultu atımlı faylar ile temsil edilir. Daha önceden ileri sürülen hipotezlerin aksine, yakın zamandaki jeolojik, jeodezik çalışmalar ve mikro sismik aktivite Anadolu Bloku içerisindeki deformasyon sürecinin sürekli olduğuna işaret etmektedirler. 240 km uzunluğundaki Malatya Ovacık Fay Zonu (MOFZ), Anadolu Bloku içerisindeki KD doğrultulu sol yanal deformasyon kuşaklarından biridir. Önceki hipotezler MOFZ?nin sürekli bir deformasyon zonu olmadığını ve 3 milyon yıldan bu yana aktivitesini yitirdiğini ileri sürsede, fay üzerinde yapılan jeolojik, jeodezik çalışmalar ve mikro sismik aktivite bu görüşün aksini destekler. Bununla beraber, MOFZ?nin güncel deformasyon özellikleri hakkında az sayıda veri bulunurken paleosismik tarihçesi hakkında veri bulunmaz. TÜBİTAK 114Y580 numaralı proje kapsamında, Malatya Fayı (MF)?nın (a) morfokronoloji temelli kayma hızı, (b) paleosismik tarihçesi ve (c) uzun dönemli kayma hızı üzerine yoğunlaşılmıştır. Kozmojenik 36Cl, 26Al ve 10Be izotopları ile 1.700 m ötelenmiş Tohma Deresi taraçalarının yaşlandırılması, MF?nin son 1,4 milyon yıllık dönemi için ortalama 1,21 mm/yıl kayma hızına ve bölge için 92 ±11 metre/milyon yıl yükselim hızına işaret etmektedir. Kayma hızı değerinin elde edildiği segmentin kuzeyinde yapılan paleosismoloji çalışmalarının ortaya çıkardığı 2275±606 yıllık deprem tekrarlanma aralığı, GPS verilerine göre daha düşük olan kayma hızı değerini desteklemektedir. Malatya Fayı?nın kuzeyinde ölçülen ve en fazla birikimli atım değeri olan 7,3 km, son 1,4 milyon yıllık kayma hızı değerini yansıtan 1,21 mm/yıl ile oranlandığında MF?nin yaşı yaklaşık olarak altı milyon yıl olarak hesaplanır. Ancak morfometrik indis çalışmalarına göre, daha fazla deformasyon olan fayın kuzeyinde, kayma hızının da fazla olduğu düşünüldüğünde hesaplanan bu yaş MF için en yaşlı tarihtir.

İncele

Zabci, Cengiz; Akyüz, H. Serdar; Sançar, Taylan

The North Anatolian Fault showed a remarkable seismic activity especially between 1939 and 1999, when the westward migrating earthquake sequence created surface ruptures more than 1000 km, leaving unbroken only the Marmara segments, to the west, and the Yedisu Segment, to the east along the main strand of the fault. To understand the palaeoseismicity of the Yedisu Seismic Gap, we undertook trench investigations close to the village of Balaban SarA +/- kaya, on the western part of the Yedisu Segment. We found evidence for at least five surface faulting earthquakes, from which only two are correlated with the 18 July 1784 CE and 27 June 1583 CE historical events. Although the surface rupture of the 1784 CE was reported by other trench studies, the evidence of 1583 CE event is presented for the first time. In consideration with other historical earthquakes, affecting the region east of Erzincan, we suggest that this particular section of the North Anatolian Fault may be in a seismically quiescent period, following a cluster of earthquakes in its near history. In order to test this hypothesis, further studies are needed to increase our knowledge on the temporal and spatial seismic behaviour of the Yedisu Segment, which has potential to create an earthquake with M (w) similar to 7.2 in the near future.

AtıfWoS15·OpenAlex23

İncele

Sançar, Taylan; Zabci, Cengiz; Akyüz, H. Serdar; Sunal, Gursel; Villa, Igor M.

AtıfOpenAlex19

İncele

Zabci, Cengiz; Sançar, Taylan; Akyüz, H. Serdar; Kiyak, Nafiye Gunec

AtıfOpenAlex18

İncele

Polat, Ali; Tatar, Orhan; Gürsoy, Halil; Karabacak, Volkan; Zabci, Cengiz; Sançar, Taylan

İncele

Zabci, Cengiz; Akyüz, Husnu Serdar; Karabacak, Volkan; Sançar, Taylan; Altunel, Erhan; Gürsoy, Halil; Tatar, Orhan

AtıfOpenAlex31

İncele