Landslide Susceptibility Zonation along NH 1D from Sonamarg to Kargil, North Western Himalaya

Abstract

The National Highway 1D from Sonamarg to Kargil is known as one of the most landslide susceptible areas in Kashmir and Ladakh divisions. The aim of the present study is to delineate landslide susceptibility zones along National Highway 1D from Sonamarg to Kargil, north western (NH) Himalaya. Based on landslide influencing geo-environmental factors such as slope angle, landuse/landcover, distance to faults, precipitation, soil, slope aspect, lithology, altitude, distance to streams, and distance to road a detailed landslide susceptible map is prepared. A weighted pair wise comparison matrix is generated using Analytical Hierarchy Process (AHP). The geo-environmental factors and their derived weights through AHP were then overlaid using the index overlay module in ArcGIS 10.2 supplemented by MS Excel and MATLAB. The relationships between the conditional and trigger factors was carried out by analyzing landslide events. The results show that the area of 913.55 Km2 is covered by very high and high landslide susceptibility zones constituting 55% of the study area. These are the most tortuous and rugged zones with high occurrence and impact of landslides. The study also identified and mapped a total of 317 landslides along National Highway 1D through rigorous multiple field surveys and secondary sources. There is a frequent incidence of traffic disruptions along the road. Thus there is an urgent need to mitigate the landslide hazard particularly to avert the disruption from Sonamarg to Leh road, which causes huge inconvenience in terms of human and economic losses.