GIS based Landslide Hazard Zonation Mapping by Weighted Overlay Method on the Road Corridor of North Sikkim Himalayas, India

Abstract

Landslide Hazards Zonation Mapping is a major tool for the geographer, geologist, ground engineer, and land-use planner for landslide prevention strategies. The main outcome of the present study is to prepare a Landslide Hazards Zonation Map of the region along the North Sikkim Road Corridor in Sikkim Himalayas, an area highly vulnerable to the landslides. The initial step of this study is involved preparation of input raster layers of the landslide controlling factors. Seven controlling factors are selected for this purpose. These controlling factor-like slope, aspect, lithology, faults, river alignment, road network, and land-use are through Geographic Information System software using multi-criteria analysis. The Analytic Hierarchy Process is used to determine the weightage of the various causative factors. Weighted Overlay Method is used for the assignment of ranks and weights to each factor. The Landslide Hazard Zonation Index is then estimated with the help of a multi-criteria analysis based on assigned rank and weight given by the Analytic Hierarchy Process. Finally, Landslide Hazard Zonation Mapping is done along the study area road corridor. Based on Hazards Index, the study area is classified into four hazard zones and classified as Very High (12.12%), High (40%), Moderate (37.20%), and Low Hazard Zones (10.68%). This zonation map is helpful for landslide hazard prevention, mitigation, proper planning of tourism and land-use management, and social development along the North Sikkim Road Corridor.