Long-Term Slip Rate Estimation for Ercis Fault in East Anatolian Compressive Tectonic Block From Geologic and Geomorphologic Field Evidence

Abstract

The Ercis Fault, which bounds the northern part of the Lake Van Basin, is approximately 50 km long with right-lateral strike-slip movement in a N30-50 degrees W direction. The Ercis Fault starts in the northwest, south of Girekol Volcano, and extends to the Turkey-Iran border, and together with the caldiran Fault forms the tectonic boundary between the Turkey-Iran Block and Lesser Caucasus-Talesh Block. Offset riverbeds, fault-controlled drainage systems, deformed alluvial fans along the faults, Plio-Quaternary volcanics, and volcanic structures are geomorphic and tectonic features that show that the Ercis Fault is active in the region. This fault has played an active role in the deformation of the Eastern Anatolian Plateau, which developed as a result of collision of the Arabian and Eurasian plates. In this study, the role of the Ercis Fault in the tectonic evolution of the region was investigated using geologic, geomorphologic, and remote sensing analysis methods. According to the morphometric indices used in the study, values of 1 < Smf < 2.1, 0.2 < Vf < 3.29, 0.3 < HI < 0.5, 25 < SL < 850 and 100 < Ksn < 600 were obtained. Results show that the area has an extremely young topography and is actively uplifting. It has been determined that the uplift rate in the region has increased in the northwest and south-east compared to other areas and is more than 0.5 mm yr(-1). According to the remote sensing and field studies, an approximately 850 m right-lateral offset is observed in the Delicay River, which is cut by the Ercis Fault, and that the long-term slip rate of the Ercis Fault is 2.02 +/- 0.12 mm yr(-1).