3-D crustal structure of the Isparta angle region from local earthquake tomography

Abstract

Isparta Angle is a seismically active and complex zone in terms of tectonic and geologic features. A temporary seismic network consisting of nineteen three-component broadband stations were installed around Isparta Angle (IA) and surroundings to address some of the important questions. Detailed crustal structure of the Isparta Angle were obtained using the seismic data collected over two years from July 2006 to June 2008. Results of this study will contribute to beter characterize the crustal structure and the seismicity of the region. In this study, local earthquake data that were collected from temporary broad-band seismic array operated in the region, data from permanent stations of Kandilli Observatory and Earthquake Research Institute (KOERI), permanent stations of Disaster and Emergency Management Presidency (DEMP) and Süleyman Demirel University (SDU) in order to determine the upper crust seismic P wave velocity structure of IA and the surrounding regions by three-dimensional (3-D) Local Earthquake Tomography (LET) method. S-wave arrival times were not included due to strong attenuation and higher picking errors of S-phases. The result of tomographic processes, 3-D velocity model, was compared with the seismological and tectonic features of the region and also compared with the results of the previous studies in the region. The results suggest that low-velocity zones beneath Isparta Angle in the depth range between 0-10 km can be related to alluvial deposits, and the velocity variation below 20 km depth can be related with the transition from upper crust to lower crust.