Geographical assessment of landslide susceptibility using statistical approach

Worldwide, steep terrain is extremely susceptible to the landslip phenomenon. In the numerous hill and mountain ranges of India, landslides occur frequently and on an annual basis. Due to its significant rainfall during both the South West and North East monsoons, the Nilgiris district of Tamil Nadu is particularly susceptible to landslides. Despite being in a seismic zone, landslides were the most common natural disasters between 1865 and 2009 in this area. This has made a significant negative impact on the environment (fauna and flora) and human settlements in this region. In order to identify the proximity of their relationship, a simple statistical approach has been applied to derive it with the frequency ratio model. Moreover, frequency ratio method became valuable in validate the preferred causal factors depends on their ability to control a landslide incident since frequency ratio can explain clearly the difference of each score between landslide causative factors in each class and landslide distribution using Geograhical Information System (GIS). The result of frequency shows that the relationship between landslide occurrence and the slope shows that steeper slopes have greater landslide probabilities with the predicting rate of slope is 8.25%. Soli is the second most responsible factor for the cause of landslide with the value of 7.18%. High susceptibility area is widely spread over the western part of study area and some part in the western region.