A Comparative Evaluation of Weight-Rating and Analytical Hierarchical (AHP) for Landslide Susceptibility Mapping in Dhalai District, Tripura

Abstract

The landslide susceptibility map delineates the potential areas of landslide occurrence which is considered to be the first step for landslide hazard management. The present study focuses on the spatial analysis of landslide susceptibility in the Dhalai district using the Geographical Information System (GIS). For this purpose, landslide susceptibility maps are prepared using weight-rating and Analytical Hierarchical Processes (AHP). To analyze landslide manifestation in the present study area, different causative factors (lithology, road buffer, slope, relative relief, rainfall, fault buffer, land-use/land-cover, and drainage density) are derived as layers. The final susceptibility zonation map of weight-rating method shows that about 1.64 and 16.68 % of the total study area falls under very high and high susceptibility zones respectively. In the AHP method, the five landslide susceptibility zones are very low which accounted 14.8 % (354.35 km2) is, low 38.91 % (932.01 km2), moderate 34.75 % (832.37 km2), high 6.03 % (144.39 km2), and very high 5.51 % (131.87 km2). Both susceptibility maps show that the high susceptibility zone is restricted within the structural hilly areas and the low susceptibility zone is in the flood plain areas of the district. Both of the susceptibility maps are validated using the existing landslide distribution in the area.