Geometry of co-seismic surface ruptures and tectonic meaning of the 23 October 2011 Mw 7.1 Van earthquake (East Anatolian Region, Turkey)

The 23 October 2011 Mw 7.1 (USGS, 2011a) Van earthquake was generated by the rupture of a main thrust fault plane striking N60°E and dipping 55°NW with a very small left-lateral offset in the western part of the Bardakçı-Saray thrust fault zone located in the north of the Bitlis-Zagros Suture Zone. The incompatibly between the subsurface seismologic data and surface deformation data indicates that the fault that generated the earthquake could be blind. The main thrust fault plane developed between the northern (Erciş) and southern (Van) continental blocks and indicates that the region is under the influence of a constant NW–SE pure compressional tectonic regime. Along with the primary thrust rupture, a secondary back thrust fault, a left lateral fault with NE strike and a right lateral fault with NW strike occurred in the contraction province. Additionally, the tensional ground cracks that developed on the hanging wall block of the ruptured thrust fault plane due to intra-continental collision are either transtensional that mainly fits to left lateral strike-slip faulting, or extensional deformations on the elevated block.