Determination of the tectonic movements in the banaz fault with GNSS observations

The active tectonic structures in the West Anatolia are formed by the concurrent activity of the North Anatolian Fault System (NAFS) and Aegean extensional tectonic regime. Banaz Fault is a 25 km segment located within the Aksehir Simav Fault Zone of the city of Aksehir. In Western Anatolian Extensional Tectonic regime, multi-segment Simav fault is an active and transtensional right lateral strike-slip fault system in NW-SE trending between Sındırgı (Balıkesir) and Afyon. The fault with the total length of 205 km is divided into five fault segments; namely Sındırgı, Simav, Şaphane, Banaz, and Sincanlı from west to east. There only a few geological studies have been carried out on the Banaz fault, and there have not been any geodetic studies found in the literature. Therefore, the Banaz fault located on the seismic gap between Afyon and Uşak is very important in this aspect. In this study, 22 GNSS benchmarks were installed based on the geometry of the Banaz Fault. In the years of 2016 and 2019, 5 campaign (4 periods) surveys were carried out in monthly periods. Using the GNSS measurements obtained; first the velocity field of the region was calculated. Using the obtained velocity vectors, the amounts and directions of the strains were determined. The velocities were calculated by the assumption of the Eurasia plate fixed, and they found were between 20-29 mm / year. In addition, NE-SW expansions were observed in the north of the region while there are NS compressions and EW expansions observed in the south of the region. Since these data are obtained for 2 years, additional GNSS measurements and geological studies are required to confirm these movements.