O. Cakir et al., Forward modelling receiver functions for crustal structure beneath stationTBZ (Trabzon, Turkey), GEOPHYS J I, 140(2), 2000, pp. 341-356
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.