Seismic Hazard Zoning of Marzneabad and Taleghan Cities Based on Evaluation of Morphotectonic Indices

Morphotectonics is a science that determines the effect of active tectonics by using geomorphic indicators as a measurement and quantitative description of landforms and landscapes. Morphotectonics provides quantitative measurements that can be used to identify areas with active tectonics. In this study, using quantitative morphometric indices obtained from morphotectonic studies, a part of Central Alborz (Marzanebad and Taleghan cities) has been studied and five hierarchical anomaly indices (a∆), branching index (R), Basin shape (Ff), drainage density (Dd) and roughness coefficient (Bh) were calculated in 19 drainage sub-basins. In these areas, each of these indices is classified into five groups: very high, high, medium, low and very low, and finally the relative active tectonic index (Iat) is obtained. Based on the results of this study, the Caspian, North Alborz, Dozdben and Kandovan and North Taleghan fault basins are in very high and high groups, which indicates the impact of these faults on the active tectonics of the region. Due to these high values, it is expected that the seismic risk of the region will increase due to fault rupture. The density of recent earthquakes in the region confirms this.