Geohazard Mapping and Mitigations of Landslides Along the Road Corridor Gasera–Indeto, Oromia Regional State, Southeast Ethiopia

This study identified the causes and triggering mechanisms of landslides in the Wabe Shebelle gorge area along the Gasera to Indeto road corridor in Southeast Ethiopia using a GIS along with AHP and FR technique, and the main finding was that lithology, slope, and aspect are the most important factors. The study aimed to investigate the causes and triggering mechanisms of landslides in the area within the 3 km buffer zones along the road corridor. The study included field investigations and inventorying, characterization of geological situations, assessments of the hydrogeological conditions, and identification of slope instability variables. A GIS technique was used to map an LSM with the combination of two models (AHP and FR). The study used eight factors: slope, aspect, lithology, rainfall, altitude, road proximity, river proximity, and land use/cover. The results of the study revealed that LSZ maps performed using FR and AHP were 64.5% and 69% and the inventory shows high and very high LSZ, respectively. Rockfalls, debris/earth slides, and rockslides are commonly observed landslides in the area. Based on the analysis, lithology (basaltic and limestone formations) showed the highest contributions for landslide in the area. Slope and aspects show the most frequent landslide hazards in > 40 and 30–40 degrees, and east and northeast, respectively. Generally, the study found that lithology, slope, and aspect were the main factors contributing to slope instability in the study area. The produced landslide susceptibility map is very important for urban planners, agricultural studies, environmentalists, and future landslide hazardous prevention and mitigation strategies.