Landslide hazard zonation using GIS and bivariate statistical model Information value and surface density in Neka Gelevard watershed, Mazandaran

Landslide is one of the natural disasters which causes the losses of life and property annually all over the world. One of the solution for decreasing the losses of landslides is to determine susceptible zones for landslide and to zoning its risk through preparing risk-based zoning map of landslide. In this paper, the effectiveness of both information value and area density for zoning the risk of landslide have been evaluated in Neka, Gelevard watershed basin. Therefore, at first, we prepared inventory map of landslide in the basin. Then, 9 effective factors in landslide occurrence and related maps have been prepared. The grade of each layers was measured via area density and information value models and then the risk maps of landslide has been prepared by combining these layers in Ar GIS software. The results showed that slope, direction of slope, fault existence, the efficacy of agricultural and lithology are the most important effective factors for landslide occurrence in the studied area. Quality index (Qs) and Preciseness (P) was investigated to compare the methods and evaluate their efficacy. The higher value of these indexes for information value model shows it has more efficacy than area density for zoning landslide.