Landslide Susceptibility Mapping Using GIS-Based Likelihood Frequency Ratio Model: A Case Study of Pakyong—Pacheykhani Area, Sikkim Himalaya

Abstract

Himalayan region has highly undulating terrain which is a witness of ongoing orogeny process. The region comes under major seismic zone. These combined geo-environment factors cause numerous occasions of landslides and subsequently major loss of life and property. Landslides in the Himalayan terrain are sometime highly inaccessible. But geospatial technique provides capability of reaching every part of the inaccessible area, identifying all types of landslides and determining landslide prone zone on the basis of major causative factors. The study was carried out to prepare the Land Slide Hazard Zonation mapping using geospatial techniques in the two Gram Panchayat Unit (GPU) namely: Pakyong and Chalamthang-Pacheykhani in East District of Sikkim state. Remote sensing data and Toposheets were used to delineate drainage pattern, lineaments, structural features, lithological features, soil and land/use land/cover type of the study area by applying digital image processing techniques. Apart from the above, Digital elevation model data was used to generate primary topographic attributes namely, slope, aspect, and relative relief. Analyzed the various factors that influence the landslides. Weightage have been given to each and every layer using frequency ration model in geospatial environment. Integrated the weightage layers for the preparation of land slide hazard zonation mapping of the study area.