Crustal structure in and around the East Anatolian volcanic belt by using receiver functions stacking

Abstract

This study aims to explore the crustal seismic properties across the East Anatolian volcanic belt. Teleseismic receiver functions obtained through deconvolution in the time domain are used to estimate crustal discontinuities and Moho interface. Further, slant stacked method, employed for the first time in the study region, is applied to identify the arrival times of P to S conversion and reverberations (Ps and PpPms) that give Vp/Vs ratio beneath each station. For slant stacking method, radial receiver functions are calculated using deconvolution based on frequency domain. Inversion results indicate that Moho depth varies from at most ∼40 km near the Bitlis-Zagros thrust zone to 45 km in the northeastward of Quaternary volcanic centers. The southwest of study region is characterized overall by a low average crustal Vp/Vs ratio (less than 1.71), implying a felsic crustal composition. A high average crustal Vp/Vs ratio of 1.82–1.87 is found near volcanic centers, characterized by predominantly a mafic crustal composition. The prominent crustal low-velocity zones especially around the Nemrut and Ararat volcanoes are identified below ∼20 km depth and likely imply the presence of partial melt zones or active magma chambers in the region. As a result, the findings of this study provide useful new constraints to the crustal thickness and composition in the study region.