Fuzzy gamma based geomatic modelling for landslide hazard susceptibility in a part of Tons river valley, northwest Himalaya, India

Himalaya, being an active orogen, is continuously undergoing tectonic activities that pose threats of land stability on the mountains. A large number of mass movement occurrences have been observed in a part of the Tons river valley area. Remote sensing and geographical information system (GIS) based techniques have been used to derive and analyse various parameters and attributes pertinent to the landslide hazards. The GIS based analysis in the present work, incorporating the fuzzy membership values from the existing landslides, has been used for spatial modelling of the parameter maps including geology, slope amount, slope aspect, weathering, erosion, drainage influence, tectonic influence and landuse/land cover for landslide hazard zonation. The model has been used to spatially classify the study area into zones of very high, high, moderate, low and very low landslide hazard zones. Eighty-five percent of the active landslides have been observed to occur in very high and high hazard zones.