The analyzing and assessment of share's role of factors on theRock flow's occurrence, by using of bivariated methodsCase study: Garangoo catchments (eastern slope of Sahand Mt.,NW of Iran)

Catchment of Garangoo is as a semi-arid region (from 46゜. 27´ to 47゜. 42 E, from36゜. 58´ to 37゜. 44´N) and is as largest catchment of Sahand mountain. The RockFalls and Rock Flows, as one type of mass movement and as marked ofgeomorphologic hazard, frequently are occurred on rocky slope of semi-arid mountain.These events are the natural outcome of natural processes which the occurrences ofevents are intensive with human impacts and are threat the human structure ,speciallyin mountain area and are imposed economical damage to villager The environmentmanagement is require firstly, to study mechanism of the occurrence of these eventsand then zonation of susceptible area to the occurrence events. The aim this article isassessment share of factors and is define share of 10 factors on the occurrence of Rockflow. The Rock flow hazard mapping is often performed through the identification andanalysis instability factors .For mapping ,firstly distribution map of factor produce anddigitized of factors and then analyzed by bivariated methods and the next stage,weighted to factors and final stage, produced Rock flow hazard zonation map by usingof Arc/View .This map show that, large part of Garangoo catchment is consist ofvolcano ash ,marl and old alluvial ,with steep slope at site of 2000 m altitude. Thevolcanic material (andesite and dasite) specially Miocene volcanic stone,produced thedebris and rock segments. These materials deposited on roads surface and distortedpassengers.