Crustal structure variation in western Turkey inferred from the receiver function analysis

Abstract

We have used receiver function analysis employing teleseismic waveforms to investigate variations in crustal and upper-mantle velocity structure beneath the western Turkey. The genetic algorithm is adopted to avoid the inherent non-uniqueness problems of the inversion. The total of 50 teleseismic waveforms recorded by 25 permanent stations is analyzed and the selected records of earthquakes distributed in three quadrants from each seismic station in the years from 2007 to 2008 are analyzed. 2-D images of Moho variation beneath the western Turkey along two profiles are 700 and 300 km long and extended from the Aegean Sea coast to the central Anatolia and southeastern Anatolia respectively are estimated. The depth-migrated receiver function showed almost well resolved Moho for the two profiles. Although the limited quantity of data is used to short periods, the resolution and confidence level is not so bad. For the one profile that extended from the Aegean Sea coast to central Anatolia, we obtain Moho depths between 25 and 35 km. On the other profile along the western coast, the Moho depths range from 20 and 30 km. Shear wave speed was found to vary between 3.3 km/s and 3.7 km/s in the lower crust, and between 4.1 km/s and 4.4 km/s uppermost mantle. We concluded that the Moho depth is increasing from western Anatolia to central Anatolia considering inversion results and 2-D depth-migrated receiver functions.