Quantifying the impact of changing rainfall patterns on landslide frequency and intensity in the Nilgiris District of Western Ghats, India

Abstract

Changing rainfall patterns on vulnerable hill slopes are a significant factor in increasing landslide frequency and resulting damages. In the Nilgiris district of the Western Ghats, India, recent shifts in rainfall patterns, including increased overall precipitation and more erratic downpours, have raised concerns about landslide occurrences. This study examines the correlation between the altering rainfall patterns and the occurrence of landslides in a quantitative manner. A thorough analysis of rainfall data from 1992 to 2022 using R (hydroTSM) is conducted to evaluate its impact on landslides. Using the Analytical Hierarchy Process (AHP), a comprehensive Landslide Susceptibility Map (LSM) is generated by incorporating twelve significant landslide causative factors. The results indicate that 1% of the study area is in the very high susceptibility zone and 18% in the high susceptibility zone. These findings are crucial for developing targeted mitigation strategies, effective land use planning, and ensuring the safety of the region's inhabitants and infrastructure.