Chapter 4 - Application of analytical hierarchy process (AHP) in landslide susceptibility mapping for Qazvin province, N Iran

Abstract

Landslide is a downward movement of soil and rock masses on slopes. This phenomenon caused many human and financial losses worldwide. Considering different affecting factors, various methods proposed for landslides zonation. In this study, we used the analytical hierarchy process (AHP), a semi-quantitative method, for zoning the landslide hazard in Qazvin province-N Iran. In this way, we considered data such as slope, elevation, slope aspect, layer dip-topographic slope difference, lithology, land use, rainfall, distance from rivers, distance from faults, distance from roads, point load index, geological strength index (GSI), specific gravity, cohesion, internal friction angle, weathering, and condition of discontinuities as effective factors for landslide occurrence. After analyzing and importing factors in ArcGIS software, their effects on landslides are determined using the AHP method and a landslide hazard zonation map was prepared. Comparison of this zonation with the distribution of historical landslides indicates that AHP is a suitable method for landslide hazard zonation. After the slope angle factor, the lithology factor especially Miocene dolomitic limestones and sandstones with shale units have the greatest effect on landslides in the study area.