Landslides susceptibility assessment by analytical network process: a case study for Kuttiyadi river basin (Western Ghats, southern India)

In the case of Western Ghats of Kerala located in southern India, landslides become the most devastating hazard during the monsoon season is mainly because of intense rainfall. The recent landslides struck in the months of June and August 2018 were the worst in the history of the state as the damages to life and property happened were very dangerous. From this evidences, being a landslide-prone area a hazard zonation attempted using the terrain susceptibility concept for highlands of Kuttiyadi river basin is a part of Western Ghats in Kozhikode district with a maximum elevation of 1640 m above MSL. Through landslide susceptibility mapping, the assessment of areas likely to have or probable to landslides in the future identified using geospatial and multi-criteria decision-making (MCDM) tool mix. This work explores the usage of the MCDM tool-analytical network process (ANP)-based decision-making approach to determine the relationship between each landslide conditioning factors and to assign weight effectively. Factor maps of various landslide triggering parameters such as slope, soil, landuse, drainage density, stage of landform, lineament density, geology, and geomorphology were prepared and integrated through geospatial analyses in the GIS platform, and the study area (318 km(2)) is categorized into four classes of unstable (121 km(2)), moderately unstable (76 km(2)), stable to moderately stable (124 km(2)), high vulnerability (67 km(2)), and very high vulnerability (74 km(2)). The result of this work concluded that the application of ANP is an effective tool to weight the factors causing landslides and to generate landslide susceptibility zonation map with maximum accuracy using geospatial technology. The validation of output data with landslide inventory data is satisfying it.