Landslide hazard zonation using AHP model and GIS technique in Khoram Abad City

Extended abstract1- Introduction The increasing growth of urban and rural development has caused some natural anomalies in the Earth's inhabitants. Mass movements, especially landslides, are one of the most damages of them that have had the increasing momentum together human manipulation in natural systems in recent decades. So that it is one of the principal geomorphic processes in the mountainous areas. Landslide phenomenon occurring in many parts of the world and Iran in the favorable conditions causes the destruction of vegetation, orchards, farmlands, and even human casualties. According to estimates, landslides have imposed much financial damages about 500 milliard Rials to Iran, annually. Burying of Abikar village of Charmahal-o-Bakhtiari Province in spring 1997 year is one of the clear samples of landslide human damage. Among these, the Lorestan Province is one of the most susceptible sites of landslide occurrence in Iran. The occurrence about 274 landslides in Lorestan Province, with extent 1400km2 equivalent %4.8 of its area confirm this claim. Since the exact predication of landslides occurrence isn’t possible by human sciences, thus, we can prevent from the damages of this phenomenon by identification of landslide susceptible areas and prioritizing them. Landslide hazard zonation maps can help the environmental designers and engineers to select a suitable place for development projects implementation. The results of these studies can be used as fundamental information by environmental managers and planners.The purposes of this study are the recognition of effective factors in landslide and the zonation of Khoram Abad City in terms of the occurrence of this phenomenon using the AHP model and GIS technique. Therefore, selection of criteria and standards, providing of factors raster layers, determining of relative and final weight of factors, overlaying of layers and preparing landslide hazard zonation map are the major objectives of this research to determine sensitive sites that have the maximum occurrence probability of landslide. 2- Methodology The studied area is Khoram Abad City, center of Lorestan province, which has been located in the 32o, 45َ to 34o North latitude and 47o, 30َ to 49o East longitude (Fig. 1).At first, study area was investigated and determined its extent using satellite images of Google Earth and 1:50000 topographic maps. Then, according to Geological, Geomorphologic, Hydrological, Climatic, Human and Environmental charac