Landslide Susceptibility Mapping of the Kaushalya River Catchment, Solan, Himachal Pradesh, India: A Frequency Ratio Approach in a GIS Framework

Abstract

Landslide-affected roads are widespread within the Kaushalya River catchment, including the Pinjore-Dharampur stretch of NH-5, Kumharhatti-Nahan, Chakki Mod-Bhojnagar, and other link roads. A 30 m resolution Shuttle Radar Topography Mission (SRTM) based Digital Elevation Model (DEM) was utilized to delineate the Kaushalya River catchment. Landslide Susceptibility Map (LSM) was prepared for the Kaushalya River catchment. The DEM was further processed to derive slope, aspect, elevation, terrain roughness index (TRI), and curvature. Other conditioning factors including geology, land use and land cover, distance to road, distance to stream, distance to fault, and rainfall, were examined using a field-verified inventory of 213 landslide incidents. This study applies the Frequency Ratio (FR) method by integrating 11 conditioning factors within a GIS framework to assess landslide susceptible zones using Prediction Rate (PR). The resulting susceptibility map classified the catchment into five zones: very low, low, moderate, high, and very high. Model validation using Receiver Operating Characteristic (ROC) curve analysis yielded an Area Under the Curve (AUC) value of 0.747, which predicts a very good accuracy of LSM. The findings offer spatially explicit hazard information to assist regional planners, transportation engineers, and disaster management agencies.