GIS ابزاري كارآمد در تعيين سياست ها و برنامه هاي مديريت خطر زمين لغزش

GIS an efficient tool for identifying policies and programs of landslide hazard management

Landslide is one of natural hazards that makes numerous financial and life damages each year. Therefor we must detect susceptible areas, and with prioritizing of them, policies and programs of landslide hazard management will be offered in order to reduce landslid occurance hazard and damages. In this study, landslide hazard is zoned using multivariate regression model at a part of Alamout watershed in general level (1/50000 scale). Then, by two parameter including landslide hazard and installation existence, watershed was prioritized for use of management programs. So first landslide distribution map of area was prepared using study of air photos and field visitations. After reviewing available resources along with reviewing the benefit of experts, eight parameters including (lithology, slope, aspect, height, distance to foult, land use, rain and earthquake acceleration) were selected as landslide effective factors. AHP and pair comparing technique was used for quantitating of qualitative catagouries of land use, aspect, and lithology parameters. Results of stepwise method shows that there is high correlation bettwen five parameters including lithology, slope, height, distance to foult, land use, and occurred landslides. Determination coefficient between these parameters as constant variable and logharithm of landslide area as dependent variable was 60.7. Potential landslide hazard map was provided with this equation using geographic information system (GIS) and crossing layers in Arc gis software. Chi square test was used for comparing of difference between hazard 32 classes of models. Results shows that measured chi square rate is meaningful at 99% of confidence TfT interval, and there is suitable dissociation among landslide hazard classes. 42 percent of watershed area is located in hazard classes of I&II and dosnt need to any specific management program. About 47 percent of area is located in hazard classes of III & IV that maintain of existent condition is the policy of management in these areas. About 10 percent of area is located in hazard classes of V &VI that considering installation existence or not two policies including hazard control and avoiding of hazard must be used respectively.