Seismogenic zones in Eastern Turkey

Abstract

A 29‐station temporary broadband PASSCAL network was operated from late October 1999 to August 2001 in eastern Turkey in order to decipher the geodynamics of one of the youngest continent‐continent collision zones in the world. This paper focuses on the hypocentral distribution of local earthquakes located during the operation of the network and provides new insights into the active faulting in the Anatolian plateau. A total of 1165 earthquakes were located and classified into four different categories based on the reliability of the locations as established by the data coverage. The accuracy of the locations ranked in the best two categories is estimated to be less than approximately 5 km. The results show that seismic activity in Eastern Turkey is higher than previously documented and there were no subcrustal earthquakes beneath the Arabian‐Eurasian collision zone or beneath the Anatolian plateau during our deployment. This result suggests no or very little underthrusting of the Arabian plate beneath Eurasia. Our results also suggest that the North Anatolian Fault zone extends farther toward the southeast, well beyond the Karliova triple junction, and that a number of unmapped active, seismogenic faults exist in the region. We also observed a possible difference in the seismogenic thickness of the East Anatolian fault zone (EAFZ) and the North Anatolian fault zone (NAFZ).

Single Station Sigma for Turkish Strong Motion Stations

“…All the record entries of this database have corresponding measured average shear wave velocity for the upper 30m of soil profile, V s30, values [21]. An upper limit for depth in accordance with the study of [22] was selected for this database so that it only includes shallow event data. The magnitude, distance, site class and style of faulting based distributions of the strong motion data used in this study are given in the figures below.…”

Evaluation of Liquefaction in Ercis Plain during Van Earthquake

“…Türkelli et al (2003) indicates that a combination of these processes formed the seismo-tectonic nature of the area. Figure 2 depicts the seismo-tectonic map of the area.…”

“…This area is one of the youngest intercontinental collision zones on earth, where the Arabian Plate collides with the Eurasian Plate to form the Turkish-Iranian Plateau, causing movement along the North and East Anatolian Fault zones (Türkelli et al 2003). Figure 1 shows tectonic boundaries and plate motions in Eastern Turkey and surrounding regions that include the City of Van.…”

“…1 Tectonic boundaries and plate motions in Eastern Turkey (after Türkelli et al 2003) which manifest itself as a right-lateral strike-slip movement along the North Anatolian fault system (NAF) and the left lateral strike-slip movement along the Eastern Anatolian fault system (EAF) (Dewey and Şengör 1979, Şengör and Kidd 1979, McClusky et al 2000, Türkelli et al 2003. The NAF and EAF have been active since the Miocene (Barka and Kadinsky-Cade 1988) and are associated with large pull apart basins, such as the Karliova Basin located at the junction of these two fault systems (Hempton 1985).…”

Crustal S-wave structure around the Lake Van region (eastern Turkey) from interstation Rayleigh wave phase velocity analyses

“…The Eastern Turkey Seismic Experiment (ETSE) project was performed by Sandvol et al (2003b) using the earthquake data of 29 V-shaped broadband PASSCAL stations in this region. Data recorded via these stations of this project have been used and processed by many authors with different methods , 2004Gök et al, 2003Gök et al, , 2007Sandvol et al, 2003a;Türkelli et al, 2003;Zor et al, 2003;Angus et al, 2006;Lei and Zhao, 2007;Özacar et al, 2008;Zor, 2008;Biryol et al, 2011;Gökalp, 2012;Delph et al, 2015b) and they have supplied new approaches for the 3-D crust and mantle dynamics of the region. Al-Lazki et al (2003) interpreted low (<7.8 km/s) Pn velocities under the Anatolian Plateau as most likely the absence of the mantle lid, just as AlLazki et al (2004) observed the same velocities at the broad-scale in eastern Turkey and surrounding regions associated with hot, unstable mantle lid zones and active volcanism starting from the Late Miocene.…”