Vulnerability of highways to landslide using landslide susceptibility zonation in GIS: Mandi district, India

Landslides pose a significant threat to transportation infrastructure, particularly in mountainous regions. This study investigates the vulnerability of highways to rainfall-induced landslides in the Mandi district of Himachal Pradesh, India, using a Geographic Information System-based approach. It employed six landslide susceptibility zonation (LSZ) models—Frequency Ratio, Weight of Evidence, Information Value, Shannon Entropy, Analytic Hierarchy Process, and Certainty Factor—to assess the spatial distribution of landslide risk. Fifteen geo-environmental factors were considered, including topography, geology, hydrology, land cover, and geotechnical characteristics. The analysis revealed that the Frequency Ratio model exhibited the highest accuracy, with a 90.14% success rate and 90.06% predictive rate. The resulting LSZ map identified high and very high-risk zones encompassing 31% of the study area. These zones pose a significant threat to road network in the district, with 49% of landslides occurring within a 500-m buffer of roadways. The study highlights the vulnerability of critical transportation infrastructure to landslide events, emphasizing the need for effective mitigation strategies to minimize economic losses, protect communities, and ensure safe and reliable transportation in the region.