Spatio-temporal analysis of landslides in Himachal Pradesh, Northwestern Himalaya: assessing vulnerability and impact

Abstract

Landslides, the downslope movement of rock and debris, are short-lived but highly destructive events, often triggered by reduced shear strength of slope materials. Their frequency is rising globally due to both natural and human factors that is urbanization, deforestation, and large-scale infrastructure development. This study area is the Himachal Pradesh, located in the tectonically active area of Himalayas, is among the most vulnerable regions which leads to such hazards. In this study we have applied a spatiotemporal analysis of landslides using historical records from the Himachal Pradesh State Disaster Management Authority and satellite imagery. The results show that over 97% of the area is susceptible, with Kullu, Chamba, and Solan districts being most at risk. The Swarghat–Bilaspur stretch of National Highway 21 demonstrates landslide activity linked to the Main Boundary Thrust (MBT) and Gambhar Thrust. Both natural drivers – steep slopes, weak lithology, and heavy rainfall – and human activities such as road building, tunneling, and deforestation intensify slope instability. This research integrates spatial mapping with temporal patterns, offering a comprehensive view of vulnerability hotspots. In Himachal Pradesh, districts such as Kinnaur and Kullu have experienced above normal rainfall correlating with increased landslide events. Conversely, districts like Mandi, Kangra and Solan, despite below-normal rainfall, continue to report high landslide frequencies, suggesting that short-duration, high-intensity rainfall events – hallmarks of climate change – may be triggering slope failures. The findings highlight the urgent need for disaster management for such areas and sustainable land-use planning in the region.