Identification of Effective Factors on Landslide Occurrence and its Hazard ‎Zonation Using Dempster-Shafer theory, Case study: Vanak Basin, Isfahan ‎Province‎

Landslides are major natural hazards and adopting a regional strategy is very necessary to reduce its damages and maintains natural and human resources. The purposes of this study are the recognition of effective factors in landslide and the zonation and assessment of in terms of the occurrence of this phenomenon using the Dempster-Shafer theory and GIS technique. In this research with integration of Landslide map and effective factors maps such as lithology, land use, slope angle, slope aspect, elevation, precipitation, distance to fault, distance to road, and density of drainage were done analysis of hazard. Finally, landslide occurrence zones were recognized from very low risk to very high risk. Total area of region is 1780516, 12/66 percentage of area (237259) existed in very high risk,12/78 percentage of area (239045) existed in high resk, 21/24 percentage of area (397316) existed in medium,29/33 percentage of area (548649) existed in low and 23/96 percentage of area (448247) existed in very low class. Model evaluated using one to third of landslide points, Frequency Ratio (FR), Seed Cell Area Index (SCAI) and ROC. The results show that Frequency Ratio and Seed Cell Area Index indicate appropriate accuracy of classification to 5 class. Also accuracy of ROC in Dempster-Shafer theory with AUC (%73) indicate high correlation between Risk map and Landslide hazard map and good evaluation of model.The results of these studies can be used as fundamental information by environmental managers and planners.