Need for detailed landslide inventory maps and landslide databases in Indian context

Abstract

Landslide inventory maps are important for sustainable disaster management as they are critical inputs for hazard and risk assessment. They document the distribution, failure type, material, dimensions, and other details regarding slope failures in a region. In the Indian context, preparing a complete landslide inventory is still a challenging task due to various factors. This study demonstrates a case study from Kerala, India, where multiple landslides happened in October 2021 along a road stretch. The events along the road stretch were mapped from field investigation three days after the events and from post-event satellite images. Among the 56 landslides detected from the field, only three were spotted using the multispectral natural colour images from satellites. The verticality of failures, thick vegetation and higher cloud cover during monsoons severely affects the visibility of landslides from satellite images. Even though many shallow landslides go undetected, the details of dimensions and flow directions of large-sized events including debris flows are better understood from satellite images. The study demonstrates the gap between field- and satellite-based landslide inventory mapping for areas with thick vegetation and emphasises the need for standard methods for preparing landslide inventory maps. © 2025 selection and editorial matter, Sreevalsa Kolathayar, N Vinod Chandra Menon and Sreekeshava K S. All rights reserved.