Influence of anthropogenic activities on landslide susceptibility: A case study in Solan district, Himachal Pradesh, India

Landslides in the Himalayan region are primarily controlled by natural parameters, including rainfall, seismic activity, and anthropogenic parameters, such as the construction of large-scale projects like road development, tunneling and hydroelectric power projects and climate change. The parameters which are more crucial among these are a matter of scientific study and analysis. This research, taking Solan district, Himachal Pradesh, India, as the study area, aims to assess the impact of anthropogenic activities on landslide susceptibility at a regional scale. Landslide distribution was characterized into two groups, namely Rainfall-Induced Landslide (RIL) and Human-Induced Landslide (HIL) based on triggering factors. Multiple data such as slope angle, aspect, profile curvature, distance to drainage, distance to lineament, lithology, distance to road, normalized difference vegetation index (NDVI) and land use land cover (LULC) have been considered for delineating the landslide susceptibility zonation (LSZ) map. The effect of anthropogenic activities on landslide occurrences has been examined through the distribution of landslides along national highways and land use land cover changes (LULCC). Two sets of LSZ maps with a LULC of time interval covering five years (2017 & 2021) were prepared to compare the temporal progression of LULC and landslide susceptibility during the five years. The results indicated the significant impact of anthropogenic activities on the landslide susceptibility. LSZ map of the year 2021 shows that 23% area falls into high and very high susceptible classes and 48% area falls into very low and low susceptibility classes. Compared to LSZ map of 2017, high and very high susceptible classes have been increased by 15%, whereas very low and low susceptible classes have been reduced by 7%. The present case study will help to understand the potential driving parameters responsible for HIL and also suggest the inclusion of LULC in landslide susceptibility analysis. The study will demonstrate new opportunities for research that could help decision-makers prepare for future disasters, both in the Indian Himalayan region and other areas.