Source mechanism and stress analysis of 23 October 2011 Van Earthquake (Mw = 7.1) and aftershocks

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

“…Geophysical studies were also inadequate for determining the spatial and temporal details of the aftershock clusters around the hypocenter of the mainshock (Bayrak et al 2013;Elliott et al 2013;Fielding et al 2013;Utkucu et al 2013;Moro et al 2014). Furthermore, the land-based observations that were conducted were insufficient to describe the overall rupture geometry and the detailed seismic activity (Altıner et al 2013;Kalafat et al 2013;Utkucu 2013). Prior to the present study, little was known about the focal depth nature of aftershock seismicity and structural coupling to rupture complexity at crustal depths.…”

“…Some selected events of the aftershock activity constrained by relocated catalog picks are also compared with the data set performed by previous studies (Gülen et al 2002;Irmak et al, 2012;Bayrak et al 2013;Fielding et al 2013;Kalafat et al, 2013;Toker 2013;Toker 2014). The comparison indicates that overall geometric pattern of the individual events reveal the same relocated seismicity structure of Irmak et al, (2012) based on the same KOERI data set with focal depth uncertainties of 1-2 km (Irmak et al, 2012) and 2-3 km (Bayrak et al, 2013;Kalafat et al, 2013). Considering that the structure is highly complex, and based on the relocations given in this study and also the data set performed by previous studies, this study proposes a focal depth location uncertainty of ~1-2 km.…”

Multiple parameter analysis for assessing and forecasting earthquake hazards in the Lake Van region, Turkey

“…Different seismotectonic parameters of earthquake occurrences in the Lake Van region have been addressed in numerous statistical studies. Comprehensive assessments of seismic, tectonic, structural, morphological, and volcanic parameters based on the correlation between different geophysical data have been provided by numerous researchers (Utkucu 2006;Selçuk et al 2010;Inan et al 2012;Irmak et al 2012;Kalafat et al 2014;Dogan et al 2014;Demirkesen, Evrendilek 2017;Öztürk 2018;Akkaya, Özvan 2019;Toker et al 2021;Alkan, Bayrak 2022). Their study results indicate that the Lake Van region falls into a high-level earthquake hazard zone as regards potential intermediate-and long-term occurrences of strong earthquakes.…”

“…Hence, the results obtained by Irmak et al (2012) support the results of our study. Kalafat et al (2014) analyzed the fault-plane solutions of the 2011 Van earthquake and its aftershocks to define the deformation and stress regime in the Lake Van region. The distribution of strong earthquake events and aftershocks proved that seismicity in the region was caused by faults trending east-west and northeast-southwest.…”

Active tectonic stress field analysis in NW Iran-SE Turkey using earthquake focal mechanism data

“…To compute the optimum stress tensor using earthquake focal mechanisms, 277 mechanisms were collected from various sources, including Jackson et al (1995), Mostriouk and Petrov (1994), Bernardi et al (2004), Pinar et al (2007), Siahkali Moradi et al (2009Moradi et al ( , 2011, Irmak et al (2012), Görgün (2013), Nemati (2013), Kalafat et al (2014), Ansari et al (2015), Donner et al (2015), Tseng et al (2016), Afra et al (2017), Momeni and Tatar (2018), Solaymani-Azad et al (2019), Hosseini et al (2019), Lukk and Shevchenko (2019), Global Centroid Moment Tensor (GCMT), Kandilli Observatory and Earthquake Research Institute (KOERI), International Seismological Centre (ISC), and United States Geological Survey (USGS). One difficulty concerning the gathered data set is the different focal mechanism solutions reported for the same event.…”