Forward modelling receiver functions for crustal structure beneath stationTBZ (Trabzon, Turkey)

We use teleseismic three-component digital data from the Trabzon, Turkey br oadband seismic station TBZ to model the crustal structure by the receiver function method. The station is located at a structural transition from con tinental northeastern Anatolia to the oceanic Black Sea basin. Rocks in the region are of volcanic origin covered by young sediments. By forward model ling the radial receiver functions, we construct 1-D crustal shear velocity models that include a lower crustal low-velocity zone, indicating a partia l melt mechanism which may be the source of surfacing magmatic rocks and re gional volcanism. Within the top 5 km, velocities increase sharply from abo ut 1.5 to 3.5 km s(-1). Such near-surface low velocities are caused by sedi mentation, extending from the Black Sea basin. Velocities at around 20 km d epth have mantle-like values (about 4.25 km s(-1)), which easily correlate to magmatic rocks cropping out on the surface. At 25 km depth there is a th in low-velocity layer of about 4.0 km s(-1). The average Moho velocity is a bout 4.6 km s(-1), and its depth changes from 32 to 40 km. Arrivals on the tangential components indicate that the Moho discontinuity dips approximate ly southwards, in agreement with the crustal thickening to the south. We se arched for the solution of receiver functions around the regional surface w ave group velocity inversion results, which helped alleviate the multiple s olution problem frequently encountered in receiver function modelling. Station TBZ is a recently deployed broadband seismic station, and the aim o f this study is to report on the analysis of new receiver function data. Th e analysis of new data in such a structurally complex region provides const raining starting models for future structural studies in the region.