Analytic hierarchy process and information value method-based landslide susceptibility mapping and vehicle vulnerability assessment along a highway in Sikkim Himalaya

In hilly areas, highway projects can be a cause of landslides as well as an element of vulnerability due to landslides. Hence, landslide susceptibility mapping of highway corridors can substantially mitigate loss of life and property. For this, a Landslide Susceptibility Assessment Model (LSAM) was developed for a corridor of 27 km along NH 10 in the East Sikkim. Landslide inducing factors viz. Aspect, Distance from Fault, Distance from Road, Drainage Density, Land use and Land cover, Lithology, Plan Curvature, Rainfall, Slope, Soil Depth, and Soil Texture were considered for the study. Results show that areas in proximity to the highway and areas with steeper slope had a higher landslide susceptibility than otherwise. Spatial explicit sensitivity analysis indicated that LSAM was sensitive to distance from the highway and slope. Vehicle vulnerability assessment of base year and horizon years showed that vulnerability increased through time. LSAM is appropriate for hazard mitigation for areas with poor historical data on landslides.