Landslide susceptibility analysis using weight of evidence

Bayesian probability model, using the weight-of-evidence method, have applied to the task of evaluating landslide susceptibility using GIS data. The location chosen for the study was the Janghung area in Korea, which suffered substantial landslide damage following heavy rain in 1998. Using the location of the landslides, and topographic factors such as soil, forest and land use, the weight-of-evidence method was used to calculate each factor´s rating. Tests of conditional independence were performed for the selection of the factors, allowing the large number of combinations of factors to be analyzed. For each factor´s rating, the contrast value, W⁺ and W^-, was overlaid for landslide susceptibility mapping. The results of the analysis were verified using the observed landslide locations, and among the combinations, the slope, aspect, curvature, soil material and timber types show the best results.