Application of Frequency Ratio Method for Landslide Susceptibility Mapping at the Thulo Lumpek Area, Gulmi, Nepal

The application of the Frequency Ratio method for landslide susceptibility mapping was implemented in the Thulo Lumpek area of the Gulmi District in western Nepal. A landslide inventory map was prepared using the recent Google Earth image and field verification. Landslide causative factors maps were prepared in GIS and a final landslide susceptibility map was prepared. Stratigraphically, the rocks of the study area can be classified into two lithological units: the Nourpul Formation and the Dhading Dolomite of the Nawakot Group of the Lesser Himalayas. Landslide is influenced by multiple factors, including the adverse geological structure, and anthropogenic influences. Most of the landslides are concentrated within the rocks of the Nourpul Formation and the contact region between the Nourpul Formation and the Dhading Dolomite. The susceptibility map was classified into four landslide susceptibility classes, i.e., low (39.67%), medium (18.82%), high (17.41%), and very high (24.10%). Sindi, Kasingthala, Ghardada, and Goskot villages were categorized in the very high landslide susceptibility class. The 0.7832 AUC value with an overall success rate of 78.32% also validated the landslide susceptibility map with the existing slope instability conditions. Presently prepared susceptibility map is believed to be important for land use planning and hazard management in the Thulo Lumpek area.