Gis Based Landslide Susceptibility Mapping And Assessment Using Bivariate Statistical Method: In North Bench District, Snnpr, Ethiopia

Abstract

Natural disaster management like landslide requires spatial information as a pillar of awareness and mitigation process. In that perspective, analysis of landslide susceptibility becomes crucial. North Bench district in south western highland of Ethiopia is one of such prone and frequently disrupted landslide due to its geo environmental condition. Therefor this study aims in preparing landslide susceptibility map using GIS and remote sensing technologies. The bivariate statistical method (Frequency ratio and Information value) was employed to find the best fitting function based on the relation between the landslide event and eight landslide causative factor (Slope, v Aspect, Elevation, Curvature, Distance to stream, Lithology, Land use and Rainfall).The thematic map preparation and exporting to ASCII file was completed in GIS environment, and the coefficient value of the major factors are used in spatial probability calculation by raster calculator in spatial analysis tool. The prepared landslide susceptibility map has been classified into four classes very low, low, moderate, and high landslide susceptibility, and validated using area under curve (AUC) and landslide density index (LDI) .As the value of area under the curve (AUC) of frequency ratio (84.1 %) is greater than information value method (83.9 %) method, the frequency ratio method was perform better than the information value. This result implies that one third of the target area is under critical condition which needs serious land use planning and further investigation.