North Anatolian and East Anatolian faults beyond Karlıova in the east

Abstract

The vicinity of Karliova, located at the intersection of two major fault systems in Turkey, is a seismically active region with a tectonically complex structure, however; there is little information about the east of Karliova, to what extent in the east the seismic activity continues. Investigating the possible extensions of the North Anatolian Fault (NAF) and the East Anatolian Fault (EAF) to the east of Karliova is therefore significant target to verify if there is a strain accumulation and therefore unknown earthquake hazard in the region. In this study, possible extensions of the NAF and the EAF in the east of Karliova were investigated using GPS slip rates. In this context, historical and instrumental period earthquakes had been compiled to identify potential indications for the possible extensions of the NAF and the EAF in the east of Karliova. With the focal mechanism solutions, it has been observed that the tectonics of this particular region is dominated by mostly strike slip structures. Fault information in previous studies conducted in the region was compiled to locate of potential eastern extensions to be used in the analysis. Also, the all-available GPS stations were homogenously combined (CORS-TR and campaign-based GPS measurements) to achieve the best possible station coverage to characterize tectonic surface deformation in the region. Using combined GPS data, Arctangent profiling analysis and block modeling analysis were performed to determine the location and movement of the potential extensions of the NAF and the EAF. The results of the analysis have shown that there is a strike slip faulting activity in the east of Karliova suggesting continuation of the NAF and the EAF in the east. The NAF extends ~ 170 km southeast of Karliova, by the slip rate of about 10.3 mm/y. The EAF extends ~ 180 km northeast of Karliova, by the slip rate of about 5.8 mm/y. For both fault systems, slip rates drastically decrease to the east of Karliova, down to the half of their slip rates in the west.