Landslide Risk zoning by Anbalagan Method Using GIS (Case Study: Tanyan Dehestan watershed)

Landslide is a sudden integrated movement of a volume of soil and material on the surface of the slopes that is transferred to the downstream of the slopes. In recent years, the occurrence of landslides in the northern regions of the country has increased due to land use changes, forest destruction and road construction. Landslides and rockfalls are examples of mass movements of the earth, landslides on mountain and forest roads cause direct and indirect damages in various ways, and damages include restrictions on forest management and exploitation, destruction and destruction of habitats. Also, in addition to the loss of lives, landslides cause major financial losses, the loss of livestock of villagers and the destruction of infrastructure and agricultural lands; Therefore, by knowing about landslides, it is possible to prevent their occurrence and stabilize the landslide. This research, using the descriptive-analytical method and using field observations and documentary and library studies, investigated the range movements in the watershed of Tanian district and according to the analysis of the geological map, faults, topography, slope, direction of slope, land use and its changes. In the past years, it has zoned the areas prone to landslides based on the Anbalagan model in 15 working units and has fully identified the sensitive areas; Therefore, high risk areas with an area of 1,606 hectares equivalent to 38%, medium risk areas with 2,350 hectares equivalent to 56% and low risk areas with 219 hectares equivalent to 6% were determined, and at the same time, it has provided necessary solutions to reduce damages and injuries. This can help planners and decision-makers in various fields such as soil and natural resource protection management, environment, determining road routes, passive defense (facilitating crisis management, planning, locating, etc.) in the watershed of Tanian village.