Coulomb Stress Changes and Magnitude-Frequency Distribution for Lake Van Region

Abstract

The tectonic structure of Turkiye is under the influence of Arabian, Eurasian, African, and Anatolian plates. Lake Van region, located in eastern Turkiye, has been exposed to many devastating earthquakes in historical and instrumental periods. In this paper, using regional earthquakes, the tectonic stress variation of Lake Van region was investigated using the Coulomb stress change and the b-value distribution. 83 earthquakes that occurred between 2000 and 2020 are used to calculate the Coulomb stress change, while 17815 earthquakes that occurred between 1903 and 2021 are used to calculate the b-value distribution. Coulomb stress change gives an idea about the transfer of energy to nearby faults. Coulomb stress change and b-value distribution maps were created at different depths to model the variation of stress. The low b-values and positive Coulomb stress values were especially observed around the Van and Yenikosk faults. On the contrary, no significant variation in stress change was observed around Suphan and Nemrut volcanoes, and high b-values were calculated in this region. Coulomb stress change and earthquake epicentral distribution are compatible and most events occurred in positive stress regions. In conclusion, stress change and b-value distribution were interpreted together and positive stress regions were revealed in the region.