Crustal Structure of Eastern Anatolia from Single-Station Rayleigh Wave Group Velocities

Abstract

In this study, crustal structure of the Eastern Anatolia has been obtained by inverting group-velocity dispersion data of fundamental mode Rayleigh waves, using single-station method in the period range of 4-40 seconds approximately. For this purpose, we have used recordings of mainshock and its aftershocks of the 2011 Van Earthquake recorded on KOERI (Kandilli Observatory and Earthquake Research Institute) broad band (BB) stations (ERZN, DARE, GAZ, KMRS, RSDY, SARI, SVRC, SVSK, URFA). The fundamental modes of vertical component broad-band seismograms are isolated to higher modes. 1-D shear velocity structure of the region is obtained from observed fundamental mode group velocity dispersion curves and their inversion results. We have also calculated the normalized statistical resolution matrix to obtain resolution-length information for total inverse system. The Normalized statistical resolution matrix could not only measure the resolution obtainable from the data, but also provided reasonable spatial/temporal resolution or resolution-length information.  

Considering the locations of selected events, we have created three distinct groups and averaged the group velocity dispersion curves. The mean dispersion curves of Rayleigh waves have been inverted to determine shear wave structure represents the study region. According to inversion results, the crustal thickness is approximately 42 km in the study area and Vs velocity ranges between 4.19-4.29 km/s. It is clearly seen that shear velocities vary from ∼2.8–3.2 km/s in the upper crust (10-12 km) to ∼3.5–3.7 km/s in the lower crust (22-24 km). These values are compatible with other studies’ values.

Keywords

• Eastern Anatolia, Crustal Structure

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