Palaeozoic-Recent geological development and uplift of the Amanos Mountains (S Turkey) in the critically located northwesternmost corner of the Arabian continent

<p>We have carried out a several-year-long study of the Amanos Mountains, on the basis of which we present new sedimentary and structural evidence, which we combine with existing data, to produce the first comprehensive synthesis in the regional geological setting. The ca. N-S-trending Amanos Mountains are located at the northwesternmost edge of the Arabian plate, near the intersection of the African and Eurasian plates. Mixed siliciclastic-carbonate sediments accumulated on the north-Gondwana margin during the Palaeozoic. Triassic rift-related sedimentation was followed by platform carbonate deposition during Jurassic-Cretaceous. Late Cretaceous was characterised by platform collapse and southward emplacement of melanges and a supra-subduction zone ophiolite. Latest Cretaceous transgressive shallow-water carbonates gave way to deeper-water deposits during Palaeocene-Eocene. Eocene southward compression, reflecting initial collision, resulted in open folding, reverse faulting and duplexing. Fluvial, lagoonal and shallow-marine carbonates accumulated during Late Oligocene(?)-Early Miocene, associated with basaltic magmatism. Intensifying collision during Mid-Miocene initiated a foreland basin that then infilled with deep-water siliciclastic gravity flows. Late Miocene-Early Pliocene compression created mountain-sized folds and thrusts, verging E in the north but SE in the south. The resulting surface uplift triggered deposition of huge alluvial outwash fans in the west. Smaller alluvial fans formed along both mountain flanks during the Pleistocene after major surface uplift ended. Pliocene-Pleistocene alluvium was tilted towards the mountain front in the west. Strike-slip/transtension along the East Anatolian Transform Fault and localised sub-horizontal Quaternary basaltic volcanism in the region reflect regional transtension during Late Pliocene-Pleistocene (<4 Ma).</p

YAPAY ETKİNLİKLERİN GÖKSU DELTASI GELİŞİMİNE ETKİSİ, MERSİN-TÜRKİYE

Anadolu'nun güney kıyılarında Akdeniz'e çıkıntı oluşturan Göksu deltası, hem Türkiye'nin hem de Doğu Akdeniz'in en önemli sulak alanıdır. Delta, kıtalararası göçmen kuşların uğrak yeri ve koruma altındaki Akdeniz memelilerinin üreme-yaşama ortamıdır. Son yarım yüzyıldır deltanın doğu kesimlerinde deniz aşındırma dinamikleri etkisiyle kıyı gerilemektedir. Buna karşın deltanın güncel ağız bölgesi lagün boğazına doğru ilerlemektedir. Ayrıca, kıyı kumulları ve kıyı setlerinden rüzgarla taşınan malzeme ve yarıntı çökelleri lagün alanlarını doldurmaktadır. Deltada meydana gelen değişimlerin nedenlerini ortaya koymak ve çözüm önerileri getirmek amacıyla delta ortamındaki güncel dinamik süreçler ayrıntılı araştırılmıştır. Elde edilen bulgulara göre, delta ortamındaki doğal akarsu sistemi, kıyı dinamiği ve rüzgar erozyonu süreçleri, yapay müdahaleler sonucu değişmiştir. Bu değişimlerin devam etmesi deltada ekolojik değişikliklere neden olacaktır

The East Anatolian Fault: geometry, segmentation and jog characteristics

<p>A detailed account is given of the fault geometry and segment structure of the East Anatolian Fault Zone as a whole based on mapping of active faults, supported by available seismological and palaeoseismological data. We divide the East Anatolian Fault into two main strands: southern and northern. The main southern strand is <em>c.</em> 580 km long between Karlıova and Antakya, and connects with the Dead Sea Fault Zone and the Cyprus Arc via the Amik triple junction. The northern strand, termed the Sürgü–Misis Fault system, is <em>c.</em> 350 km long and connects with the Kyrenia–Misis Fault Zone beneath the Gulf of İskenderun. We infer that slip partitioning between the main and northern strands of the East Anatolian Fault accommodates 2/3 and 1/3 of the slip rate of the lateral motion between the Arabian and Anatolian plates, respectively in the Çelikhan–Adana–Antakya region. Taking account of the time elapsed from the latest events on the East Anatolian Fault, we suggest that the Pazarcık and Amanos segments have the potential to produce destructive earthquakes in the near future. </p

Paleosismolojik bulgular ışığında Orhaneli Fayının Holosen aktivitesi, Bursa, KB Anadolu

Orhaneli Fayı, Biga Yarımadası’nda yer alan yaklaşık 30 km uzunluğunda, ters bileşeni baskın, sağ yönlü doğrultu atımlı bir faydır. Kuvaterner yaşlı Orhaneli Havzası’nın güney sınırını bu fay kontrol etmektedir. Bununla birlikte söz konusu fay aynı zamanda Tavşanlı Zonu’na ait metamorfik kayaçları, Kretase yaşlı ofiyolitik birimleri ve Neojen/Kuvaterner yaşlı sedimanları kesmekte olup hava fotoğrafl arında ve arazide belirgin çizgiselliği ve fay sarplıkları ile kolayca takip edilebilmektedir. Fay boyunca gözlenen uzamış sırtlar, ötelenmiş vadiler ve topoğrafik boyunlar, fayın aktivitesine işaret eden önemli jeomorfolojik unsurlardır. Bu çalışmada Orhaneli Fayı üzerinde gerçekleştirilmiş olan ilk paleosismolojik çalışmaların sonuçları yer almaktadır. Bu kapsamda fay üzerinde iki adet hendek açılmıştır. Serçeler ve Kusumlar olarak adlandırılmış bu hendeklerde, Tavşanlı Zonu’na ait metamorfik kayaçların fay tarafından Kuvaterner yaşlı sedimanlar üzerine itildiği belirlenmiştir. Yapılan çalışmada, Kuvaterner’de yüzey yırtılmasıyla sonuçlanmış dört büyük depremin izlerine rastlanmıştır. Serçeler hendeğinde, en eski depremin MÖ 22.000±3.200 ile MÖ 6.600±800 arasında, son depremin ise MÖ 770-415 den önce gerçekleştiği belirlenmiştir. Kusumlar hendeğinde ise, en eski depremin MÖ 6.600 ile MÖ 3.085 arasında, son olayın ise MS 650 tarihinden sonraki bir dönemde gerçekleştiği belirlenmiştir. Söz konusu eski depremler arasında tekrarlanma periyoduna ilişkin bir yorum yapılamamıştır. Bu çalışma ile Orhaneli Fayı’nın Holosen aktivitesi kanıtlanmıştır. Toplam uzunluğu 30 km olan ve iki segmentten oluşan bu fayın tek parça halinde kırılması halinde, Mw= 6,87 büyüklüğünde bir deprem üretme potansiyeline sahip olduğu belirlenmiştir

A probabilistic seismic hazard assessment for the Turkish territory: part II-fault source and background seismicity model

WOS: 000438615600008Over the years, several local and regional seismic hazard studies have been conducted for the estimation of the seismic hazard in Turkey using different statistical processing tools for instrumental and historical earthquake data and modeling the geologic and tectonic characteristics of the region. Recently developed techniques, increased knowledge and improved databases brought the necessity to review the national active fault database and the compiled earthquake catalogue for the development of a national earthquake hazard map. A national earthquake strategy and action plan were conceived and accordingly with the collaboration of the several institutions and expert researchers, the Revision of Turkish Seismic Hazard Map Project (UDAP-C-13-06) was initiated, and finalized at the end of 2014. The scope of the project was confined to the revision of current national seismic hazard map, using the state of the art technologies and knowledge of the active fault, earthquake database, and ground motion prediction equations. The following two seismic source zonation models are developed for the probabilistic earthquake hazard analysis: (1) Area source model, (2) Fault and spatial smoothing seismic source model (FSBCK). In this study, we focus on the development and the characterization of the Fault Source model, the background spatially smoothed seismicity model and intrinsic uncertainty on the earthquake occurrence-rates-estimation. Finally, PSHA results obtained from the fault and spatial smoothed seismic source model are presented for 43, 72, 475 and 2475 years return periods (corresponding to 69, 50, 10, and 2% probability of exceedance in 50 years) for PGA and 5% damped spectral accelerations at 0.2 and 1.0 s.AFAD (Disaster and Emergency Management Authority of Turkey) [UDAP-C-13-16]First, we would like to express our gratitude to Sinan Akkar for his kind coordination of the project titled as "The update of the seismic hazard maps of Turkey'', and to Mustafa Erdik for his suggestions and comments, which helped us to considerably improve the project. We would like to thank various local researchers who gave us feedback and comments: Tolga Yilmaz, Ahmet Yakut, from Middle East Technical University; Murat Utkucu from Sakarya University. We also acknowledge Laurentiu Danciu from ETHZ, Roberto Basili from INGV, and Tuba Eroglu Azak who wrote and improved the codes and some scripts used in the calculation of some parameters. The study has been sponsored by AFAD (Disaster and Emergency Management Authority of Turkey) under Project Code UDAP-C-13-16. We would also like to thank Dr. Baumont for his review and suggestions for the improvement of the manuscript

The Manyas fault zone (southern Marmara region, NW Turkey): active tectonics and paleoseismology

The Manyas fault zone (MFZ) is a splay fault of the Yenice Gönen Fault, which is located on the southern branch of the North Anatolian Fault System. The MFZ is a 38 km long, WNW–ESE-trending and normal fault zone comprised of three en-echelon segments. On 6 October 1964, an earthquake (Ms = 6.9) occurred on the Salur segment. In this study, paleoseismic trench studies were performed along the Salur segment. Based on these paleoseismic trench studies, at least three earthquakes resulting in a surface rupture within the last 4000 years, including the 1964 earthquake have been identified and dated. The penultimate event can be correlated with the AD 1323 earthquake. There is no archaeological and/or historical record that can be associated with the oldest earthquake dated between BP 3800 ± 600 and BP 2300 ± 200 years. Additionally, the trench study performed to the north of the Salur segment demonstrates paleoliquefaction structures crossing each other. The surface deformation that occurred during the 1964 earthquake is determined primarily to be the consequence of liquefaction. According to the fault plane slip data, the MFZ is a purely normal fault demonstrating a listric geometry with a dip of 64°–74° to the NNE

A probabilistic seismic hazard assessment for the Turkish territory-part I: the area source model

WOS: 000438615600007The seismic zoning map of Turkey that is used in connection with the national seismic design code (versions issued both in 1997 and 2007) is based on a probabilistic seismic hazard assessment study conducted more than 20 years ago (Gulkan et al. in En son verilere gore hazA +/- rlanan Turkiye deprem bolgeleri haritasA +/-, Report No: METU/EERC 93-1, 1993). In line with the efforts for the update of the seismic design code, the need aroused for an updated seismic hazard map, incorporating recent data and state-of-the-art methodologies and providing ground motion parameters required for the construction of the design spectra stipulated by the new Turkish Earthquake Design Code. Supported by AFAD (Disaster and Emergency Management Authority of Turkey), a project has been conducted for the country scale assessment of the seismic hazard by probabilistic methods. The present paper describes the probabilistic seismic hazard assessment study conducted in connection with this project, incorporating in an area source model, all recently compiled data on seismicity and active faulting, and using a set of recently developed ground motion prediction equations, for both active shallow crustal and subduction regimes, evaluated as adequately representing the ground motion characteristics in the region. The area sources delineated in the model are fully parameterized in terms of maximum magnitude, depth distribution, predominant strike and dip angles and mechanism of possible ruptures. Resulting ground motion distributions are quantified and presented for PGA and 5 % damped spectral accelerations at T = 0.2 and 1.0 s, associated with return periods of 475 and 2475 years. The full set of seismic hazard curves was also made available for the hazard computation sites. The second part of the study, which is based on a fault source and smoothed seismicity model is covered in Demircioglu et al. in Bull Earthq Eng, (2016).AFAD (Disaster and Emergency Management Authority of Turkey) [UDAP-C-13-16]We would like to express our gratitude to Sinan Akkar for having initiated this collaborative effort for the update of the seismic hazard maps of Turkey, to Mustafa Erdik for his invaluable suggestions and guidance throughout the study, and to the participants of the various work packages for their active contributions to the discussions during the course of the project. The study has been sponsored by AFAD (Disaster and Emergency Management Authority of Turkey) under Project Code UDAP-C-13-16. We would also like to thank Gabriele Ameri for his review and suggestions for the improvement of the manuscript

VAN GÖLÜ (EDREMİT KÖRFEZİ) KUVATERNER ÇÖKELLERİNDE TEKTONİK DEFORMASYONLAR, DOĞU ANADOLU, TÜRKİYE

3 Ekim 2011 Van Depremi (Mw: 7,2) ters fay nitelikli Van Fay Zonu (VFZ)’ndan kaynaklanmıştır. Depremde fay üzerine rastlayan mühendislik yapılarında 10 cm’ye ulaşan yerdeğiştirmenin izlendiği bir yüzey deformasyonu gelişmiştir. VFZ karada D-B genel doğrultusunda ve 28 km uzunluğundadır. Fayın batı ucu Van Gölü içerisindedir. Bu çalışmada, VFZ’nun kara ve deniz araştırma yöntemleri kullanılarak detay haritalanması, Van Gölü’ndeki sualtı devamlılığının incelenmesi, kara ve sualtı verilerinin ortak değerlendirilmesi ile Edremit Körfezi’nin Kuvaterner’deki tektonik yapısı ve evriminin ortaya konulması amaçlanmıştır. Kara verisi, VFZ tavan ve taban bloğunda Kuvaterner birimlerini etkileyen D-B uzanımlı kıvrım eksenlerinin varlığını göstermiştir. Kıyı ötesi çalışmalarda ise sığ sismik profilleme (GeoAcuoustics) ile çok ışınlı batimetrik veri toplanması çalışmaları sonucunda VFZ’nun sualtı bölümünün karaya benzer özellikler sergilediği ortaya konmuştur. Sismik kesitlerde göl tabanında yer alan Kuvaterner istifinde, eksenleri fay zonunun uzanımına paralel olan kıvrımlar fayın her iki bloğunda da açıkça görülmektedir. Çarpanak burnunun devamındaki su altı sırtı, karada olduğu gibi fayın tavan bloğundaki bir yükselim yapısına karşılık gelmektedir. 23 Ekim 2011 depremi ile ilişkili yüzey deformasyonları VFZ’nun tavan bloğundaki geniş bir zonda gelişmiştir. Araştırma bulguları, VFZ boyunca Kuvaterner’de meydana gelen deformasyonların en son depremde gelişen deformasyonlarla uyumlu olduğunu göstermiştir