Fathollah Naderi - PhD student in Geomorphology, Department of Environmental Management, Sistan and Baluchestan University, Zahedan, Iran
Yasem Khanmohammadian - PhD student in Biological Sciences, Ilam University, Ilam, Iran
Mohammad Taghi Koosha - Master of Natural Resources - Forestry, Ilam University, Ilam, Iran

Each Landslide phenomenon is one of the various forms of amplitude movements and intensifies soil erosion that has irreversible effects. The purpose of this study is to assess the risk of landslides in Ganjvan watershed of Ilam province using fuzzy actuation with ۰.۷, ۰.۸ and ۰.۹ lands in GIS environment. First, using field visits and satellite images, landslides in the basin were identified and then their distribution map was prepared (۲۸ landslides). Among the effective factors in landslide occurrence, ۷ factors including lithology, altitude, slope, distance from fault, distance from waterway, distance from road, land use were selected as the main variables. In order to evaluate the accuracy of zoning maps, Qs qualitative sum index was used. The results of map evaluation showed that the value of Qs index for ۰.۷, ۰.۸ and ۰.۹ landings is equal to ۰.۷۱, ۰.۶۸ and ۰.۶۲, respectively. Therefore, we conclude that the fuzzy gamma operator with ۰.۷ landing is better than other fuzzy landings in landslide zoning in Ganjvan watershed.

Zoning, Landslide, Fuzzy gamma, GIS, Ganjvan watershed, Ilam