پهنه بندي زمين لغزش در حوضه ي آبخيز توتكابن با استفاده از مدل هاي كمي

Land Slide Zoning in Tutkabon Water Shed Basinby Use of Quantity Models

Land Slide is a kind of slope movement which tends to move surface materials of very steep slopes. Northern slopes of Alborz mountain under the effect of humid climate and environmental conditions has a high potential in comparing with the other regions of Iran from the view point of occurring the slope movements .The under study basin (Tutkabon) is located in Rudbar town ship. Recording more than loo slides in the basin during the field investigations shows high potential of this basin for land slide occurrence .The purpose of this research in identifying the effective factors on land slide Zoning and also determining the potential of different regions at this basin from the view point of land slide occurrence, in order to decrease the resulting damages. After recording the existing land slides and transferring it on the map, by regarding different variables such as sediment thickness, slope direction, slope, distance from stream, vegetation cover, Litho logy and height, the regions with Instability have been recognized. For this purpose, Three methods were used, grading effective variables, valuing the informative layers and surface density. The main tools for research is the use of ILWIS Microsoft software and the working technique was comparing the influencing rate of variables by using the said methods. Research results through showing Zoning maps in from of the mentioned software and analyzing the zones which are exposed to danger have been divided into the results including, the zone with very low relative danger, low relative danger, Medium relative danger and finally the zones with high occurrence probability and too high danger. It is recognized that the eastern and west north of basin has the highest potentials for land slide and its northern and southern regions has a low danger for land slide occurrence and is stable. Obviously, planning for this region, particularly for the establishment of structures such as communicating roads of buildings and rural and residential constructions shall be performed with respect to the stability factor of the slopes. Keywords: Land Slide, Tutkabon Water Shed, Density, Surface Method, Rudbar Township, Slope Movement.