Analysis and Investigation of Landslide Hazard Zoning using Hybrid Model of Hierarchical Analysis and Surface Density

Identification of susceptible areas to landslide occurrence is one of the basic measures for reduction of the possible risk and hazard management. The main goal of this research is to compare the applicability of two statistical landslide hazard zonation models, valuing area accumulation and Analytical Hierarchy Process (AHP),in Ziarat Watershed, Gorgan, Golestan Province.In a review of previous works and field works, we chose nine factors of slope, aspect, elevation, lithology, landuse, river distance, road distance, fault and rainfall distance, and identified effective factors in landslide hazard, and used them to conduct an analysis risk by GIS software. Data from previous land slidesin the study area were collected and GPS. Thesenine maps were crossed with the map of previous landslides.Theamount of landslides and their areas were computed in each class. After determining the rate of each factor (element), we performed landslide zonation in GIS by combining density levels and AHP models. Theefficiency of output results of the models was assessed by Drand QS indices. The results of Drindex showed that the combination of both models was more efficient in recognizing the hazard classes with high danger (Qs=1/81) compared to those of low danger (Qs=0/78).