Assessment of Hill Side Instability Potential by Using Regional Model in the North West Part of Zagros, Regarding Leile Landslides

Zegros hillsides in some zones of these mountain chains is suitable for different mass movements. In this paper, the sensitivity of slopes at the northwest part of zagros mountain has been evaluated regarding the landslide risk of Leile zone. the aim was not only zoning the hill sides of Leile from the view point of intensity and weakness in occurrence of land sliding, but also it was for obtaining a model to distribute the hillsides zoning to other areas from instability point of view. To this end, the slopes of the considered area was zoned by using eight variables including: litho logy, slope gradient, slope morphology, slope direction, land-use type, distance from drainage, distance from road and distance from settlements or by four methods such as weight, informative value, surface density, and analytic hierarchy process (AHP); the above said parameters, with respect to the statistical relationship between spatial dispersion of 39 sliding mass were selected at the area with any type of class of variables effective on surface landslides. Selecting the above methods was made based on their extensive use by the Iranian researchers. The study results which was presented as four zoning maps in four levels i.e very high risk zone, high risk zone, medium risk zone, and low risk zone, indicates that the two variables statistical method of the surface density has the highest and weight method has the lowest conformity with the specifications of the under study area. Based on the results of surface density, about 16.86% of Leile area is faced with very high risk, 49.21% high risk and 8.57% with low risk of land sliding.