GIS-based landslide susceptibility zonation and risk assessment in complex landscape: A case of Beshilo watershed, northern Ethiopia

Abstract

Landslides necessitate comprehensive prediction of susceptible zones for timely intervention to mitigate any disaster. Present study at Beshilo-watershed in Amhara Regional State of Ethiopia was attempted to prepare landslide susceptibility zonation (LSZ) map and to carry out risk assessment. GIS-based multi-criteria decision analysis was adopted by considering factors; land-use/land-cover, slope, elevation, aspect, drainage-density, rainfall, lithology, lineament/fault density, soil depth, and texture. Factor weights were determined through Analytical Hierarchy Process (AHP) and the factor classes rating were assigned through logical judgment. Landslide susceptibility indices were determined based on a continuous numerical scale developed for this purpose. Very high and high susceptibility zones were found to spread in 1215.28 km2 and 2279.87 km2, respectively in the eastern and north-eastern parts that are characterized by high lineament/fault density, barren lands, shrubs, bushes, grassland, or croplands mostly having unconsolidated soils with shallow depth. The Receiver Operating Characteristics (ROC) curve showed acceptable results. Further, risk assessment indicated that populations in high to very high-risk zones need timely attention of the local authorities to avert any unwanted happenings.