The Seismic Velocity Structures of Western Turkey, New Magma Chamber Found as the Source of Geothermal Fields

Abstract

In order to found the heat source of the high temperature geothermal fields in western Turkey, 2929 P-waves and 2793 S-waves data gained from 41 seismic stations in Turkey to performance the 0.5°× 0.5°× 5km seismic velocity structures. 17360 P-waves and 15367 P-waves first arrived time data available have extracted, Fast Marching Method are used in ray tracing method inversion and forward algorithm based on subspace. New magma chamber has been found among the area 36.2°- 38.8°N，26.8°- 29.6°E, in the depth of 10-50km. The shallowest area is between Denizli Basin and Simav graben, especially in Kula volcano area for the obvious low seismic velocity anomaly, this result is accordance with the isotope hydrogeochemistry research and deep MT profile. The seismic velocity anomaly is coincided with the active faults in the Gediz graben and Menderes graben, which also shows these faults have reached the depth of 15km, and the temperature has below the Curie point, it provided the access for the material and thermal from the mantle when crust become thin and magma upwelling.