| Summary: In this study, crustal thickness and seismic velocity structure in the Eastern Black Sea region is investigated using single station surface wave group velocity inversion method. For this purpose, we have used the earthquake data (10 shallow earthquakes, H=5-15.5 km, their magnitudes ranging from 4.2 to 5.8 Mb) recorded on KOERI (Kandilli Observatory and Earthquake Research Institute) broad-band stations. Analyses were performed only for fundamental mode of surface waves (Love and Rayleigh waves). Group velocities were calculated by multiple filter technique (MFT) and crustal structure of each source-station path were determined from inversion of dispersion curves. Earthquakes was divided into two groups as traveling across land or/and sea. We have used the structural models given in the literature to create an initial model for the inversion of surface wave group velocities. Earthquakes traveling across land associated with whole Eastern Pontides region and the average crustal thickness has been found 41 km along the region. For the traveling paths of earthquakes from land to sea (Greater Caucasus-Eastern -Black Sea-Eastern Pontides), it has been found that the average crustal thickness is 36 km. It is deduced that the crustal velocitiy and density values decrease from North to South (towards the Pontides), while crustal thicknesses increase in the same direction. Studied region is a transition zone, containing oceanic-semi oceanic-continental crust, from oceanic (high density and basic character) in the North to continental crust (low density and acidic character) in the South. |
