LANDSLIDE SUSCEPTIBILITY MAPPING USING GIS AND REMOTE SENSING: THE CASE STUDY OF LAY-GAYINT WOREDA NORTHWEST ETHIOPIA

ABSTRACT Lay-Gayint area is found in the South Gondar Zone of Amhara National Regional State and it is 755Km far from Addis Ababa. Physiographically, it is part of the northwestern highlands of Ethiopia. This area is part of the Guna Mountain which is characterized by weathered volcanic rocks, rugged morphology with deeply incised gorges, heavy rainfall and active surface processes. Many landslides have occurred on August 2020 after a period of heavy rainfall and they caused many damages to the local people. In this study, Frequency Ratio model were applied to evaluate the landslide causative factors and generate landslide susceptibility maps. The landslide inventory map that consists of 280 active and passive landslide scarps was prepared based on intensive fieldwork and Google Earth image interpretation. These landslide locations were randomly divided into 80% training and 20% validation datasets. Twelve landslide causal factors including slope, aspect, curvature, altitude, distance to stream, land use/ land cover, NDVI, lithology, distance to were combined with a training dataset using GIS tools to generate the landslide susceptibility maps of the study area. Then the area was divided into five landslide susceptibility zones of very low, low, moderate, high and very high. Later, the resulting maps have been validated by using area under the curve method. The result showed that the success rate of 81.9% and a predictive rate of 87.9, respectively. This indicated that the LSM produced by FR model showed a better performance. Finally, the LSMs produced by FR model can be used by decision-makers for land use planning and landslide mitigation purpose.