Estimation of the crustal structure in Central Anatolia (Turkey) using receiver functions

Authors: BEGÜM ÇIVGIN, BÜLENT KAYPAK

Abstract: The receiver function analysis method was used to determine the crustal structure in Central Anatolia, Turkey, by using teleseismic earthquake records. The method is based on the conversion of incident P waves into S waves reaching an interface in the crust or upper mantle and arrival of the converted wave to the station just after the direct P waves. A temporary seismic network, the Ankara Earthquake Monitoring Network (AnkNET), consisting of six broadband seismograph stations, has been deployed in order to monitor the seismicity in Ankara and its surroundings during the period of 2007?2010. In this study, the crustal structures beneath AnkNET stations were investigated. The stations were located between latitudes 39°N and 41°N and longitudes 32°E and 34°E about 100 km apart from each other around a circle with a radius of about 100 km, including one in Ankara approximately in the center. Hypocentral parameters of 43 teleseismic earthquakes equal to or greater than an instrumental magnitude Mw of 6.5 that occurred at a distance between 30° and 100° far from the central coordinates of AnkNET (40°N, 33°E) were retrieved from the Incorporated Research Institutions for Seismology earthquake catalogue. According to the results of this study, the crustal thickness of the region is between 34.5 km and 40.5 km and the S-wave velocity varies between 3.3 km/s and 4.1 km/s. It is expected that the calculated crustal thickness and velocity values will contribute to future studies in the region.

Keywords: Crustal structure, crustal thickness, H-K stack, receiver functions, S-wave velocity structure, teleseismic earthquakes, Vp/Vs ratio

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