Prioritization of Landslide Effective Factors and its Hazard Mapping Using Weighted Linear Combination method (case study: Vark watershed)

Landslide is a kind of natural disasters causing enormous human and financial losses every year in different countries. Identification and classification of landslide prone areas and their hazard zonation are of the most important steps in the assessment of environmental risks and play an indispensable role in watershed basins management. This study attempts to determine the relative risk of slope instability and landslide occurrence in the Vark area using Weighted Linear Combination (WLC) method. As the first step, In order to assess the stability of slopes, the occurred landslides in this area was recorded using the satellite images, Google Earth software and field observations. The impact of each factor on landslides such as slope, aspect, land use, elevation, lithology, earthquake intensity and distance from fault, road, spring, and drainage were defined in the Arc GIS software. The map of each factor was standardized and weighted using Fuzzy Logic and Analytic Hierarchy Process (AHP), respectively. Investigation of the factors affecting the risk of landslides in the basin of vark indicates tow factors including the slope and the lithology have the most important role in the occurrence of landslides in the area. According to the results of using the WLC in landslide risk zonation, 13.85, 26.90, 27.81, 21.90 and 9.52 percent of the area are located in very low, low, medium, high and very high-risk classes respectively. The investigation of the risk sensitive to the risk of landslides is located in parts of the north, north west and south west areas.