Landslide Susceptibility Assessment in the Western Ghats Region of India Using a Hybrid Analytical Approach

The Western Ghats region of India is experiencing frequent rainfall induced landslides during monsoon season, which cause substantial socio-economic losses. Mapping the landslide prone areasis the first step towards establishing an effective landslide risk mitigation strategy. The present study utilized a hybrid approach that integrates Analytical Hierarchy Process (AHP) and Relative Frequency Ratio (RFR) to provide a comprehensive landslide susceptibility assessment of the region. By leveraging the benefits of both approaches, the hybrid model efficiently classifies areas that are susceptible to landslides. A total of 680 landslide locations were extracted from inventory of the Geological Survey of India. The landslide data were divided into training (70%) and testing (30%) dataset for the analysis. Ten environmental and geological causative factors including slope, rainfall, soil type, land use, elevation, aspect, curvature, distance to road, streams and lineaments were considered for analysis. The findings revealed that more than 60% of the study area was classified as high to very high susceptibility to landslides. Among the seven districts in the study area, Uttara Kannada had the maximumshare of highly susceptible areas (18.23%). The accuracy of the model was evaluated using the Receiver Operating Characteristic (ROC) curve. The hybrid model displayed its superiority over the individual models by achieving a higher Area Under the Curve (AUC) value of 0.902. The findings of the study provide useful information such as location of the highly susceptible areas, which is required for effective landslide risk management and mitigation strategies.

Keywords: Landslide susceptibility, Hybrid model, Analytic hierarchy process, Relative frequency ratio, Western ghats.