The Posht Tang drainage basin located in the north–east of Sarpol-e-Zahab in Kermanshah province. It was affected by several slope movement in resent years. We could selected six factors: litology‚ gradient‚ precipitation‚ plant coverage‚ land use and elevation from 11 factors related to effective causes of land slide occurrences using and introduction ?2 analysis by which we can predict vulnerable region to landslide by considering. Accordingly‚the six mentioned factors were overlaid and the maps of land slide hazard zonation for "Posht Tang” drainage basin were prepared by four methods: Area Density‚ Weight of Evidences‚ Modeling Hierarchical Analysis and Information Value. Finally‚ area density was introduced as the best way for spatial distribution prediction by using landslide index and it is more confident than others methods show that 42 percent of watershed area came across with much and very much vulnerability degree.
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