Tectonic Deformations in the Quaternary Deposits of the Lake Van (Edremi̇t Bay), Eastern Anatolia, Turkey

Abstract

The 23 October 2011 Van Earthquake (Mw: 7.2) was generated by the Van Fault Zone (VFZ) with reverse fault characteristics. The earthquake on the fault caused surface deformation with 10 cm displacement observed in engineering structures. On land the VFZ has general E-W strike and 28 km length. The western end of the fault is within Lake Van. This study aimed to determine the tectonic structures and evolution in the Quaternary of Edremit Bay using detailed mapping of the VFZ with land and underwater research methods, investigation of its continuation into Lake Van and common assessment of land and underwater data. Continental data showed the presence of E-W fold axes affecting Quaternary units in the hanging-wall and footwall of the VFZ. Offshore studies using shallow seismic profiling (GeoAcoustics) and multibeam bathymetric data acquisition determined that the underwater section of the VFZ had similar characteristics to those on land. Quaternary successions on the lake floor observed on seismic sections clearly showed folds in both blocks of the fault with axes parallel to the strike of the fault. The underwater ridge that is an extension of Çarpanak Cape coincides with the ridge structure on the hanging-wall block of the fault on land. Surface deformation related to the 23 October 2011 earthquake developed in a broad zone of the hanging wall of the VFZ. The research findings show the deformation along the VFZ in the Quaternary is in accordance with the deformations developing during the last earthquake.

Van Gölü Bölgesi̇nde 2011 Yili Depremleri̇ni̇n Artçi Şok Seri̇si̇ Kirilma Karmaşiğina Yapisal Bağlanti(doğu Anadolu, Türki̇ye)

“…The analyses, in this paper, of the structural coupling to the Van aftershock sequence are often associated with mapped faults in the Lake Van Basin (Fig. 5) Toker and Şengör, 2011;Çukur et al, 2013;Çukur et al, 2016;Görür et al, 2015;Özalp et al, 2016;Toker et al, 2017;Toker, 2017). The joint interpretation of aftershock sequence and seismic reflection profiles reveals the lateral and vertical heterogeneity of the faultcontrolled aftershock distribution and along-strike seismic activity in crust within the rupture area.…”