Monitoring and hazard landslide zonation in the Astara Aghchay slopes

ABSTRACT: Eastern slope of Talesh mountains because of their location which is near the world biggest closed water area Caspian sea , and their unique temperate subtropical climate in the Phytogeography classification is called Hyrcanian zone. The confined area under study as one of these mountainous geographical systems, due to it’s enjoyment of humid climate condition and homogeneous mountainous condition, densified forest vegetation shrubby and pastured vegetative cover in lower areas and that of dominance of biostasis condition even in steep slopes, for years ago was considered as one of the main centres of mass movements specially landslide. Monitoring and zonation of the landslide danger is the main purpose of this paper. To do this we have used a qualitative procedure it means a square procedure. First by means of the Present aerial photographs 1:20000, topographic maps 1:50000, geological maps 1:100000, and field survey, The distribution map of landslide was made in the form of a list map. In order to increase accuracy and easiness of this analysis all of the spatial and descriptive information such as : lithology strata , structural sing , gradient , vegetation and etc, was mentioned in number for statistical analysis of data , ( spss16) software is used then due to the gradation of the grid units sensibility to landslide occurrence, we consider influential factors and finally , the sensibility map to landslide occurrence was made. After drawing frequency diagram of different information the final map was drawn in the last step according to field studies and prepared model the zonation map was analyzed and suitable strategies were suggested to confront it.