A comparative study of fuzzy logic approach for landslide susceptibility mapping using GIS: An experience of Karaj dam basin in Iran

Preparation of landslide susceptibility maps is important for engineering geologists and geomorphologists. However, due to complex nature of landslides, producing a reliable susceptibility map is not easy. For this reason, many procedures have been used to produce such maps. Among various models this paper discusses the effectiveness of fuzzy logic approach for landslide hazard mapping. In this study a new attempt is tried to produce landslide susceptibility map of Karaj Dam Basin in Iran. To obtain the fuzzy relations for producing the susceptibility map, a landslide inventory database is compiled by both field surveys and airphoto studies. The factor maps were input into a GIS and a modified landslide hazard evaluation factor (MLHEF) rating and fuzzy membership functions as well as belief function values were assessed for each class of the factor maps. According to this map, 10% of the study area is classified as very high susceptibility, 23% as high susceptibility, 38% as moderate susceptibility, 4.5% as low susceptibility and 0.5% as very low susceptibility or nonsusceptible areas .the results show that the fuzzy set theory can integrate effectively various spatial data for landslide hazard mapping, and it is expected that some suggestions in this study are helpful to further real applications including integration, and interpretation stages in order to obtain a decision – supporting layer.