Prioritization of landslide effective factors and its hazard mapping using AHP model (A case study: Keshvari watershed)

Identify the effective variables on landslides occurrence in the basin and zoning its hazard is one of fundamental methods for management and avoiding the risk. Keshvari watershed with an area about 345 km2 is located in the 20 kilometers far from the south east of Khorram Abad city in Lorestan province. According to the tectonic and old basins division of Iran, this basin is part of folded Zagros and based on geological formations, topography, siesmology and climate, this basin is prone to landslide occurrence. In order to check the stability of slopes in this basin, in the first step landslide prone areas were identified. By merging the effective factors including slope, aspect, altitude, geology, earthquake, rainfall, landuse and distance from the fault and drainages on landslide with the landslide distribution map, impact of each of these factors assessed in ArcGIS software and then these factors were prioritized using AHP model. According the results of using the AHP in landslide risk zonation, 5.9, 38.2, 38.1, 15.79 and 2.01 percent of the area are located in very low, low, medium, high and very high risk classes respectively.