Zoning Land Surfaces of Shahroud Basin against the Occurrence of Landslides Using the Shannon Model

Mass movements of materials are divided into slip, flow and creep, among of which landslides always cause heavy financial and economic losses worldwide. In this study, based on the analysis of landslides in Shahroud Basin, effective vectors were rated. Using ArcGIS software, the spatial distribution of 183 landslides in Shahroud basin was analyzed and interpreted in fault, waterway, road, lithology, slope, aspect, precipitation amount and height. According to the effect of different vectors, and the spatial distribution of landslides in Shahroud basin, points were scored and entropy matrix was adjusted for them and landslide occurrence in Shahroud basin was zoned. Based on the results of applying Shannon entropy model in Shahroud basin for landslide zoning in terms of landslides, high-risk zones accounted for 41.79% and an average of 52.76% of the basin area. The adaptation of landslide risk zones of Shahroud basin shows the concentration of 74.86% of landslides on slopes of 10-40°, 64.97% in marl, conglomerate, and basalt lithologies, 87.97% at altitudes 2123-823m, 85.79% in semi-arid and temperate rainfall classes (685-315mm) on land surfaces with slope in the western direction, 55.74% at a distance of 0-300m from the river, a distance of 0-500m from the fault and at a distance of 1000-500m from the road. The concentration of danger and landslide zones in the two central parts of Taleghan subspecies and after the joining of Alamut and Taleghan rivers and the formation of Shahroud River is more than other areas. Such changes in landslide distribution due to nonlinear compliance of this geomorphological event are influential factors. The occurrence of landslides is a function of the interaction between factors rather than their abstract effects.