GIS-based Landslide Susceptibility Evaluation Using Analytical Hierarchy Process (AHP) Approach: The Case of Tarmaber District, Ethiopia

Landslides are one of the natural threats that often result in great loss of life and destruction of property in Ethiopia. One of the areas that is affected by landslides of different types and sizes is the Tarmaber district in the rift margin in the central part of Ethiopia. Keeping in view the cause and effect relationship and mitigation, Analytical Hierarchy Process (AHP) approach is used in the present case to understand the possible causes for landslides. Based on AHP, landslide susceptibility map is produced for Tarmaber using field survey data, remote sensing data, and geographic information system tools. The factors considered in the present case that can influence landslides are lithology, proximity to fault, land use, proximity to drainage, slope gradient, aspect and elevation. The results are validated with the inventory of landslide occurrences. The landslide susceptibility index (LSI) is calculated using the weighted -linear combination (WLC) technique based on the assigned weight and rating given by the AHP method. The accuracy of the results verified using the existing landslide locations is about 88.6%.The landslide susceptibility zonation map has identified our classes/zones: very high (29%), high (44%), moderate (20.0%) and low (7%). Keywords:  Landslide susceptibility; Analytical Hierarchy Process (AHP); Tarmaber; Ethiopia.