Evaluation of AHP and Frequency Ratio Methods in Landslide Hazard Zoning (Case Study: Bojnord Urban Watershed, Iran)

Abstract:Natural and anthropogenic factors increased the damages resulted from landslides in the last years. One of the main solutions for decreasing the landslide hazards is keeping distance from higher danger areas. For this purpose, it is necessary to prepare the landslide susceptibility map. In this research, after field studies in the Bojnord Urban Watershed, nine factors distinguished including slope gradient, aspect, elevation, precipitation, distance from road, distance from fault, distance from drainage, land use and lithology as effective factors in landslides occurrence of the studied area. After preparing the information of these nine factors in GIS environment, every layer has been crossed with the landslide layer to find the role of corresponding layer in the formation of landslide. Then hazard zoning was performed with two methods including Analytical Hierarchy Process and frequency ratio methods. Finally, in order to evaluate the verification of the hazard zoning, the obtained weights from the mentioned watershed using the above two methods were used for the adjacent basin (Chamanbid Watershed), which has similar characteristics to the urban watershed. Results showed that the AHP model give better results for landslide hazard zoning of the area.