Remote Sensing and GIS-Based Landslide Susceptibility Mapping in a Hilly District of Bangladesh: A Comparison of Different Geospatial Models

Landslide is a common hazardous phenomenon in Bangladesh's hilly areas, and Khagrachari is one of the regions that face frequent causalities due to landslide events. The present study has utilized the analytical hierarchy process (AHP) based multi-criteria evaluation techniques, frequency ratio (FR), modified frequency ratio (MFR), and information value method (IVM) approaches in the GIS environment to identify the landslide susceptible zones. The study uniquely employed 12 distinct parameters in this region to prepare the landslide susceptibility index (LSI) map of Khagrachari. The six unique LSI maps have been produced by three classification approaches, i.e., Quantile, Equal Interval, and Natural Break for decision matrix, and three different statistical modeling to compare the result. We found that the most susceptible zones of the Khagrachari district are Matiranga, Khagrachari Sadar, and Dighinala Upazila. The higher susceptibility has been primarily contributed by moderate-higher slope angle (14 degrees-68 degrees), high relative relief (176-601 m), geological structures, spares to moderate vegetation indices, and a high percentage of soil moisture (35-65%). Considering the classification approaches, around 9% of the area (similar to 676 km(2)) is classified as a very high-hazard zone. In addition, we suggest that the MFR geospatial model has better prospects than IVM, AHP, and FR, as similar to 40% of the susceptible areas include more than 80% of the total landslide areas for the modified frequency ratio model. This study emphasizes the importance of implementing specific initiatives and activities to minimize landslide risks in Khagrachari. In addition, the present study installs the groundwork for future research to enhance geospatial modeling techniques and allows for comparisons with neighboring areas, thus expanding our knowledge of landslide susceptibility in the Chittagong Hill Tracts and adjacent regions of the Bengal Basin.