Seismites as an Indicator for Determination of Earthquake Recurrence Interval: a Case Study From Ercis Fault (Eastern Anatolia-Turkey)

Abstract

The southern part of the Eastern Anatolian Plateau is a key region for understanding the tectonic activity and related deformation patterns of the Arabian-Eurasian collision zone. The geological record of seismic events collected from lacustrine deposits of Lake Van Basin is a critical requirement for seismic hazard assessment and seismic risk reduction. Our paleoseismic investigations revealed well-preserved seismites at five locations in late Pleistocene lacustrine deposits. The seismites were dated using an optically stimulated luminescence dating method and were arranged according to their ages. Their type, such as convolute, dish-and-pillar, flame, and ball-and-pillow structures, as well as their locations, ages, and stratigraphic distribution enable us to identify the responsible fault and the earthquake recurrence interval. On the basis of these properties, the Ercil Fault has been recognized as the structure responsible for creating the seismites. The time span between the seismites indicates an apparent earthquake recurrence interval of 125-250 years for large earthquakes (M >= 5) related to the Ercis Fault. The method applied here enriches our knowledge on the seismic hazards present in the northern Lake Van region.