Evaluation of Watershed Stability using Geomorphologic and Tectonics Evidence (Case study: Alvand Mountain)

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Study area is located in West of Iran with relatively rough topography. Lithologic units in the region belong from Jurassic and Cretaccous till recent era. The study area of the Alvand mountain region is related to the tectonic zone of the Sanandaj-Sirjan region and the area dominant neo-tectonic regime appears to be compressional-extensional type. One of the identification tools to find out the existence of recent neotectonic activities is tectonic geomorphology evaluation. In this study, we tried to measure the required parameters using topographic maps with scales of 1:50000 utilizing AutoCAD software. In order to identifying the morphologic landform anomalies we use asymmetry factor, transverse topographic symmetry factor and mountain-front sinuosity index. The neotectonic activity of the study area investigated by considering geologic, seismic and remote sensing evidences and with establishing relationship between these evidences and morphologic landforms. Results indicated that tilting occurred around NW-SE axis. There is a remarkable correlation between active mountain front, fault and cleavage identified (from satellite images) and position of earthquake epicenters of study area. Hence all of these evidence indicating the activity of the study area from neotectonic and instability of sub watersheds point of view.