Landslide Susceptibility Mapping of the Ghurmi-Dhad Khola Area in Eastern Nepal Using Gis

Abstract

The present study focuses on preparation of landslide susceptibility maps of the Ghurmi-Dhad Khola area, eastern Nepal using Geographic Information System (GIS). The study area consists of 77 landslides covering an area of 2.069 km2. The parameters considered for the study are geology, distance from faults and folds, distance from drainage, rock and soil type, land cover, slope aspect, slope angle and altitude. The detailed geological map of the study area was prepared along with other thematic maps for the susceptibility analysis. The methods followed for the susceptibility analysis were the heuristic and bivariate methods. In heuristic method, index-based approach was used to assess the landslide susceptibility. According to the map, an area of 24.77% falls under the high susceptibility zone whereas 18.92% of area falls under medium susceptibility and 56.31% in the low susceptibility zone. In landslide susceptibility assessment carried out using the statistical-index approach of bivariate analysis method, 28.03% of area is considered high susceptible for landslides and 21.08% of area falls under medium susceptibility zone. An area of 50.89% lies in the safe zone i.e. the low susceptibility zone. The two susceptibility maps were identical and success rate of both the maps were above 80%. Similarly there was 80.19% agreement between the two landslide susceptibility maps prepared by two different methods.