The Stress State of The Region Around Inonu-Eskisehir Active Fault System (Turkey); Kinematic Analysis Accompanied With Gps Data

Abstract

The Inonu-Eskisehir Fault System (IEFS) exhibits WNW-ESE striking right-lateral strike-slip character with a normal component that extends from Uludag (Bursa) in the west to Sivrihisar (Eskisehir) in the east and separates the west Anatolian extensional region from the central Anatolia to the northeast. This fault system consists of E-W and NW-SE trending fault sets and segments which have potential to produce destructive earthquakes. In this study, we aim to identify the stress regime of the region around Inonu-Eskisehir active fault system by correlating the fault-slip data and GPS data. The strain rates are computed using the velocity vectors from 5 Turkish National Fundamental GPS Network (TUTGA) data, acquired from the General Command of Mapping (Turkey). Fault-slip data have been analysed using the stress inversion method of Angelier. The obtained contraction rate for the studied area is about 65 +/- 15 nanostrain/yr, which corresponds to a contraction rate of 0.7 +/- 0.15 mm/yr over 10 km. The strain rate results of last ten years calculated from the TUTGA-99 data suggest approximately NW-SE trending compressional tectonic regime in the region. This strain rate and orientations are confirmed by the Plio-Quaternary slip surface data collected along the Inonu-Eskisehir Fault System.