LANDSLIDE RISK ZONING USING GIS - A FUZZY APPROACH

Abstract

Landslides are natural or man induced complex phenomenon, which cause losses to lives and property. Landslides are the outcome of several factors like landuse, slope, geology, human activity etc. It has been found that in developing countries, economic loss due to landslides is about 0.25 — 0,5%0 of GNP. In order to minimize the damages and losses due to landslides, the concept of landslide risk zonation has been introduced. In this, the areas having similar susceptibility to landslides are grouped together and subjected to remedial measures to prevent from further degradation by employing eco-regeneration program and restricting human interferences. In the present study an attempt has been made to classify the study area, which lies in Garhwal Himalaya, into different risk zones. Preparation of landslide risk zonation maps involves integration of voluminous and varied data set pertaining to several causative factors. The present study, therefore has been carried out in GIS environment. Fuzzy approach has been adopted of calculation of fuzzy memberships for different features in various themes. The weight for integrating the various themes have been computed using a spatial decision supportive system. Based upon the risk zonation maps, these prepared fraction images have been derived using fuzzy logic The customized approach, presented in this study has been found useful for preparing landslide risk zonation maps.