Active tectonics analysis based on morphometric indices; case study of Agh Chay watershed in NW Khoy

The study of Tectonic activity, and in particular those earas with relatively high activity in the Holocene and late Pleistocene is important to evaluate the earthquake hazard. The purpose of this study is to investigate the role of tectonic factors in the development and morphological changes of the alluvial fans of Agh Chay. In this study, the topographic maps, geology, satellite photos and the digital elevation model (DEM) were used as the main research data. In addition, the morphology of the alluvial fans of the region was studied closely and through the field study. Then, using the geomorphic indices which includes the sinuosity of the mountain in-front (SMF) Ratio of valley floor width to valley height (VF), Drainage Asymmetry factor (AF), Stream Length-Gradient Index (SL), Transverse Topographic Symmetry Factor (T), Fan Comicality Index (FCI), the region in terms of tectonic activities were assessed. Through combination of these indexes, the index of active tectonics (Iat) can be obtained. The results of study showed that Agh Chay, Zarabad Chay, Dibak Chay and Zavieh Chay have very high activity. Altogether, according to the calculated morphometry indexes, it can be concluded that the region has medium to high tectonic activity, but there are changes in tectonic activity in the region, which can be attributed to increase tectonic activity from north west to south east of the region.