Landslide susceptibility zonation using the fuzzy algebraic operators in GIS,Iran

The evaluation of land surface and its properties in order to identify and zone of natural hazard areas,especially landslide hazard,are subjected to researches of geomorphologists. the aim of this study was to investigate and zone of landslide susceptibility in iran with respect to the factors affecting landslide,based on the theory of fuzzy logic approach and gis containing thirteen information layers,including annual temperature,soil erosion,land use,slope,aspect,climate,elevation,distance from the streams,geology,annual precipitations,soil and distance from the fault and 4037 cases of landslide events occurred until 2007,in iran. after analyzing landslides and the other layers,the effect of each twelve information layers (previously mentioned) was determined on landslide occurrence and the classification and fuzzification of layers were done based on the occurrence percent of landslides and also by expert studies in different classes,then fuzzy functions of sum,product & gama,and,or were used to prepare the final zoning map. in order to control the verification of the output susceptibility map,the landslide susceptibility class zones on the map and the known landslides were compared. overlay of the known landslides with the landslide susceptibility map revealed that 0.9 gama has provided a better susceptibility zonation map,accordingly,35.38% of the areas of the country are in the range of moderate susceptible zone and 33.09% in high susceptible zone.