Hazard risk assessment of landslide-prone sub-Himalayan region by employing geospatial modeling approach

Ecological processes such as landslide disaster are primarily impacted by both geological and land use activities happening at different spatiotemporal scale. They specifically impact the socioeconomic development in the sub-Himalayan region of Pakistan. Ecological risk assessment and restrictive zonation mapping are therefore prerequisites for mitigation and compensation of landslide losses and risks. The current study has mapped landslide vulnerable Guoien Nullah road located in sub-Himalaya ranges of Pakistan via Landslide Hazard Zonation (LHZ) technique. Landslide active points were identified through field surveys, verified through the readings taken from Global Positioning System and mapped through geographic information system-based software. Seven landslide activating factors, i.e., slope angle, lithology, precipitation, tilt direction, land use/land cover, Normalized Differentiation Vegetation Index and elevation, were evaluated. Analytical hierarchical process (AHP) was used to assign weights to each activating factor. Precipitation, followed by lithology, and slope angle were found most influential in instigating landslide as indicated by AHP. Furthermore, three susceptibility zones were obtained using the weighted overlay method, i.e., high hazard susceptibility zone, moderate hazard susceptibility zone and low hazard susceptibility zone. The study concluded that 69% of the total landslide occurred in the high susceptibility zone which comprised of 36% of the total study area. Ground control points on active landslide sites authenticated the LHZ generated map. These maps help in restrictive zoning in the high hazard zone area that is considered important for engineers, geologists, and land use planners for future area-specific developmental projects. Besides, the current study will aid disaster management authorities, developers, policy makers and researchers in identifying the hazard disposal of the selected area.