Love-wave group velocity maps of Turkey and surrounding regions

We present the analysis of a Love-wave dispersion study performed across Turkey and the surroundings. Group velocity dispersion curves were obtained from the local and regional earthquakes recorded at both permanent and temporary stations operated in the region. Love-wave group velocity maps in the period range of 10-50 s were computed using a tomographic inversion method. The study shows the existence of significantly different crustal types in the area. The group velocity anomalies are associated with the major geological structures in the region. Low group velocities at shorter periods (10-20 s) are observed in the local sedimentary basins, the eastern Mediterranean and the Black Sea. The eastern Anatolia region is also characterized by low group velocities while Pontides and Bitlis-Poturge massif display higher group velocities. The central Anatolia exhibits uniform velocity distribution indicating more homogenous crust. The Isparta angle is marked by a wedge-shaped low group velocity anomaly. The low velocities observed in the Isparta angle are related to crustal thickening and subduction-related complex. High velocities observed on the maps are associated with metamorphics, magmatic arcs along the orogenic belts of Pontides, Poturge massif and crustal thinning in the Aegean region. At larger periods (40-50 s) the Anatolian block shows low and uniform group velocity distribution while its surroundings display higher group velocities with the exception of the eastern Mediterranean region.