The Havran-Balıkesir Fault Zone (HBFZ) is one of the major active structures of the Southern Marmara Region, which has been shaped by the southern branch of North Anatolian fault since the Pliocene. HBFZ is a 10-12 km wide, 120 km long, right-lateral strike-slip fault zone that consists of two ENE-striking main faults, namely, the Havran-Balya and Balıkesir faults. The 90-km-long Havran-Balya fault exhibits right-stepping en echelon geometry and is made up of (1) Havran, (2) Osmanlar, (3) Turplu and (4) Ovacık fault segments. On the eastern part, the 70-km-long Balıkesir fault is divided into two fault segments; (1) Gökçeyazı and (2) Kepsut. We estimated the long-term slip rate between 3.59 and 3.78 mm/yr using river offset. The Kepsut, Gökçeyazı and Ovacık fault segments are capable of generating an earthquake with a moment magnitude of up to 7.2. Detailed palaeoseismological studies show that the HBFZ is responsible for some surface faulting earthquakes with an average recurrence interval of 1000-2000 years during the late Holocene. Considering the fact that there was no evidence of a surface-ruptured earthquake for 2000 years, it can be stated that there is a seismic gap on the Gökçeyazı fault segment.

UTC), an earthquake with a magnitude of Mw = 6.8 has occurred in Sivrice district of Elazığ (Eastern Turkey). Focal mechanism solution is consistent with pure left-lateral strike-slip faulting; the location of the epicenter and fault mechanism suggest deformation along the Pütürge segment of the East Anatolian Fault Zone. A 10-day fieldwork was carried out along the Pütürge segment to study surface deformation; the geometry of the surface rupture and other seismic geomorphological structures were mapped and studied in detail. The field data are also correlated with satellite images. This paper, therefore, presents classification of seismic geomorphological structures and discuss intimate relationship between fault geometry and stress field in the region. Seismic geomorphological deformation and related features of the Sivrice (Elazığ) earthquake are observed in the area between Gezin (Elazığ) and Ormaniçi (Pütürge) villages; they are classified into two as seismotectonic and seismo-gravitational features. Field observations confirm that seismo-gravitational structures develop along both Gezin-Sivrice-Doğanbağı and Doğanbağı-Çevrimtaş-Ilıncak-Koldere-Ormaniçi sections of the Pütürge segment, while surface rupture is mapped as seismotectonic structure only along the Doğanbağı-Çevrimtaş-Ilıncak-Koldere-Ormaniçi section. Small-scale landslides, rock falls, feather cracks along asphaltic roads, and laterally discontinues ground failure-related features are common seismo-gravitational structures that developed along the fault zone. In addition, small-scale lateral spreading and liquefaction structures are common especially in areas where fault-perpendicular streams meet the Karakaya Dam reservoir. The surface rupture is mapped as stepping and overlapping en échelon fractures along elongated pressure ridges between Çevrimtaş and Doğanbağ villages, to northwest of Ilıncak village, along 1.5-km-long pressure ridge between Topaluşağı and Doğanyol, across the elongated hill that developed on an alluvial fan to the northwest of Doğanyol and in the area between Koldere and Ormaniçi villages. Surface fractures deforming the pressure ridges are all aligned parallel to the long axes of the ridges and display reverse components that give rise to small-scale pop-up structures. Interferometric SAR (DInSAR) studies indicate a 10-cm uplift in the northwestern block of the fault and a 6-cm subsidence in the southeast block. The difference in vertical movements between two blocks of the fault is interpreted to suggest that at least 30-km-long section of the Pütürge segment in the area between southwest of Sivrice and Pütürge is broken during the main shock. Although the focal mechanism solution of the main shock gives pure left-lateral strike-slip faulting, there is no significant left-lateral displacement observed during the fieldwork. This can be explained by the following: (1) left-lateral strike-slip displacement was not able to reach the surface; (2) left-lateral torque movement of the fault around a vertical axis during the earth...

The Edremit Fault Zone (EFZ) forms one of the southern segments of the North Anatolian Fault Zone (NAFZ) at the northern margin of the Edremit Gulf (Biga Peninsula, South Marmara Region, Turkey). Stratigraphic, structural and kinematic results indicate that basinward younging of the fault zone, in terms of a rolling-hinge mechanism, has resulted in at least three discrete Miocene to Holocene deformational phases: the oldest one (Phase 1) directly related to the inactive Kazdağ Detachment Fault, which was formed under N-S trending pure extension; Phase 2 is characterised by a strike-slip stress condition, probably related to the progression of the NAFZ towards the Edremit area in the PlioQuaternary; and Phase 3 is represented by the high-angle normal faulting, which is directly interrelated with the last movement of the EFZ. Our palaeoseismic studies on the EFZ revealed the occurrence of three past surface rupture events; the first one occurred before 13178 BC, a penultimate event that may correspond to either the 160 AD or 253 AD historical earthquakes, and the youngest one can be associated with the 6 October 1944 earthquake (M w = 6.8). These palaeoseismic data indicate that there is no systematic earthquake recurrence period on the EFZ.

Bu çalışmada, 14 Ocak 2017 ile 20 Mart 2017 tarihleri arasında Çanakkale-Ayvacık çevresinde meydana gelen depremlerin (Mw=5.3 ve daha küçük 1000'e yakın deprem) sismik kaynakları Şubat-Mart 2017 tarihleri arasında yapılan saha çalışmalarıyla 1/25.000 ölçeğinde haritalanmış ve ilgili faylarda kinematik analiz çalışmaları yapılmıştır. Haritalama çalışmalarımıza göre, oluşan depremlerin sismik kaynağı olan Tuzla Fayı'nın toplam uzunluğu (deniz altındaki uzantısıyla birlikte) 25 km'ye erişir ve Çamköy ile Paşaköy segmenti olarak adlandırılan iki segmentten yapılıdır. 15 km uzunluğundaki Çamköy segmenti, Tuzla Köyü'nün kuzeybatısındaki sahilden itibaren güneydoğuya doğru Tamış köyü güneybatısına kadar haritalanmıştır. 10 km uzunluğundaki Paşaköy segmenti ise, Kolfay Köyü'nden başlar ve güneydoğuya doğru Behram Köyü doğusunda Edremit Fayı ile birleşir. Şimdiye kadar oluşan depremlerin önemli bir bölümü KB-GD uzanımlı Tuzla Fayı'nın deformasyon zonu boyunca ve fayın düşen bloğu üzerindeki Tuzla Köyü ile Assos arasındaki bölgede meydana gelmiştir ve Tuzla Fayına ait Çamköy segmentinin kırıldığını göstermektedir. Henüz kırılmayan Paşaköy segmenti ise Mw=6.18 büyüklüğündeki bir deprem üretme potansiyeline sahiptir. Tarafımızdan yapılan haritalama çalışmalarına göre, iki segmente ait fay kolları Tamış Köyü güneyinde birbirine oldukça yaklaşmış bulunmaktadır. Tuzla Fayına ait iki segmentin birleşerek tek bir deprem üretmesi halinde, Mw=6.7 büyüklüğündeki bir depreme karşılık gelen enerjinin açığa çıkabileceği öngörülebilir. Depremlerin zaman ve mekân içerisindeki dağılımları ve büyüklükleri, tek bir ana şoka bağlı olarak gelişmediklerini, birbirine paralel-yarı paralel fay kollarının birbirini tetiklemesi sonucunda oluşan bir deprem fırtınası özelliği taşıdıklarına işaret etmektedir. Bu durum, Çamköy segmentinin birbirine bağlı sintetik ve antitetik nitelikli çok sayıda fay parçası içermesinden kaynaklanmaktadır. Bu fay kollarına ait kinematik veriler, Tuzla Havzası'nın KD-GB doğrultusunda gelişen çekme kuvvetleri etkisinde şekillendiğini göstermektedir.

No abstract