Analysis of Tectonic Activity and the Relationship Between Fault and landslide Hazard in Kurdistan Dam Basin

Abstract

Kurdistan dam watershed with an area of 120.15 km2is located in the northeast of Saqez city.The purpose of this study is to analyze the tectonic activity of the basin and the relationship between faults and landslide risk using the information value model. First, the region is divided into 15 sub-basins using ArcHydro software and morphotectonic indexes including Stream Length Gradient Index (SL), Asymmetric Factor (AF), Hypsometric Integra (Hi), Transverse Topographic Symmetry Factor (T) and basin shape ratio (Bs) are calculated and the results are calculated. Their evaluation was evaluated with active tectonics index (IAT). In order to evaluate the relationship between faults and landslide risk, first a map of faults and maps of factors affecting landslides were prepared by processing satellite images of Landsat 8 sensor and ENVI software and field observations. Then, using the information value model, landslide hazard map of the basin was prepared and combined with the fault map and the relationship between faults and landslide risk in ArcGIS. 10.3 environment was reviewed. The results of calculating the relative active tectonics indices show that 77.77% of the basin is tectonically active in the active class and in the information value model 55.55% of the occurrence of landslides is in the range of high instability risk. Distance coefficients from faults in both positive models and most landslides occurred at a distance of less than 1000 meters and due to active tectonics there is a significant relationship between faults and areas with high landslide risk in the basin. The results showed that the information value model has better performance for landslide risk zoning. In general, diversity of lithology, topography, abundant national and local faults and climatic conditions can be mentioned as the most important factors in the occurrence and distribution of landslides.