Fault-Slip Source Models for the 2011 M 7.1 Van Earthquake in Turkey from SAR Interferometry, Pixel Offset Tracking, GPS, and Seismic Waveform Analysis

Abstract

Online Material: Additional point‐source mechanisms for mainshock/aftershocks listed in table 2; snapshots, movie of bodywave finite‐fault model; additional information on source modeling. A large M w 7.1 earthquake struck the area north of the city of Van in easternmost Turkey on 23 October 2011. The mainshock epicenter and most of the aftershocks were located south of the eastern arm of Lake Van (Fig. 1), and extensive damage was reported in the city of Van, the city of Ercis, and many smaller towns nearby. The Lake Van region has suffered from a large number of historical earthquakes, with many causing significant damage in the last 2000 years (Table 1; Ergin et al. , 1967; Ambraseys and Jackson, 1998; Albini et al. , 2012). The region is near the center of the elevated Turkish–Iranian Plateau (also called the Anatolian Plateau) in the collision zone between the Arabian and Eurasian plates, and is well to the east of the escape tectonics exhibited along the major strike‐slip North Anatolian and East Anatolian faults (e.g., Jackson and McKenzie, 1984; Taymaz et al. , 1991, 2007; Yolsal‐Cevikbilen et al. , 2012). The plateau has an average elevation around 2000 m (Copley and Jackson, 2006; Tan and Taymaz, 2006; Podgorski et al. , 2007), and Lake Van has an elevation of about 1650 m above sea level. The Moho depth in the Van area, inferred from receiver‐function and surface‐wave analysis, is approximately 43 km, in the middle of a Moho gradient from about 40 km in the south to 50 km under the Pontides Mountains at the northern edge of the plateau (Gok et al. , 2011; Vanacore et al. , 2013). There are many Quaternary mafic volcanoes in the area (Fig. 1), which likely result from elevated temperatures in the upper mantle and possible delamination of part of the subducted …