An Integrated Approach with GIS and Remote Sensing Technique for Landslide Hazard Zonation

Landslide is among the major hydrogeological hazards that affect large parts of India, especially Himalayas, North Eastern hill ranges, Western Ghats, Nilgiris and Eastern Ghats. Landslide hazard zonation helps in identifying strategic points and geographically critical areas prone to landslides. This paper deals with an integrated approach of remote sensing and geographical information systems for landslide hazard zonation. Landslide hazard zonation simply means the division and preferably subdivision of land surface in to various zones according to the degrees of actual potential hazard caused by landslides and related phenomena. The key factor in landslide hazard mapping is the assessment and grading of risk associated with the failures. The landslide distributions are mapped by extraction of features from the satellite images. In order to analyze landslide susceptibility efficiently, the existing maps are digitized and processed with the help of integration of terrain information by GIS. Six categories of controlling factors for landslides i.e. aspect of slope, geology, land use, drainage, lineament and runoff are defined. The data obtained is integrated to form landslide hazard zonation map. An effort is made to generate a landslide susceptible map from satellite imagery, DEM (Digital Elevation Model) and maps. Finally, a map divided into four susceptibility zones is produced using the weight value of all controlling factors using the method of multi objective decision making process and then each susceptibility zone is evaluated by comparing with the distribution of each controlling factor class. Landslide susceptible map can be used to predict the occurrence of the landslide and also used for planning developmental activities in this geomorphologically fragile Nilgiris plateau.