Analyzing the criticality related to the landslide incidence using the probability models for the weight to evidence (Bayesian theory)(Case Stady: Bar Basin of Neyshabur)


Hakim Sabzevari University


Introduction One of the most important responsibilities on the applied geomorphology science is to analyze the location and value of vulnerable an endangered human environments against different geomorphical dangers. Natural incidences are complex phenomena influencing all parts of Earth globe. A research has been done about the loses made by the massive movements in Iran. The research reports that based on the Information Archive until Shahrivar, 1386, it is estimated that the loses are about 126893 milliard rials. For a number of 4900 landslies. There has been much in crease in using the Graphical models particulary the Bayesian networks to model the natural resources specially for the risk of landslide incidence in the recent decades. The purpose of this research is zoning the criticality of landslides in Neyshabur aquifer by using the probability models for weight of Evidence. The research is going to detect and determine the regions critical to landside by using this method. And finally after detecting, the executive actions should be followed in controlling the region to save the energy and the capital. Methodology In the first step, 32 tandslides and their sliding zones or locations were detected by using the sliding locations got from the information archive about Iran landslides and then A map was prepared about the disturbance of the landslides in the region. The next step included preparing an information database about the effective factors on landslides. Then the zones critical to landslide in the pressure aquifers were detected to accomplish the research by using the above mentioned data based on the probability models of weight of evidence (Bayesian) the Bayesian networks are called belief networks, casual networks and influence diagrams too. The pressure aquifers is located in northwestern part of Neyshaboor in a 40k.m distance from the north of Firoozeh town. The basin is mathematically located Between to northern latitude and to Eastern longitudes in the Sonthern slopes of Binalood mountains. Discussion The map for the Region landslides disturbance was used in the probability method of weight of Evidence to weigh and evaluate different information layers. After preparing the weight maps based on the model relations, the map for danger criticality for landslide incidence was prepared and then it was categorized into four classes or groups (low danger, Average danger, much danger and very much danger) based on the Natural Breaks. Therefore we can't use the map of region landslides disturbance to evaluate the mentioned maps and to determine their preciseness. Almost 70 percents of the sliding regions were used to model the mentioned theory and the other 30 percents were used to evaluate the above mentioned model. Then the accuracy of the prepared maps was verified by using roc curre. Finally the most precise map was suggested as the final map for evaluating the critical danger of landslide in the region. Conclusion The results obtained from considering the relations among effective factors on the landslide occurrence shows that the most of the region slides were characterized and categorized in slope degrees which is also found out from analyzing the maps prepared by suing the probability theory of Bayesian. The southern and Eastern South of the region characterizes convex form slopes having a height category of 1580-1700 m. the area is used for some garden fields, having about 0-300 m and 300-600 m distance from the fracture or rupture including the data from (Dlichai Formation) lithology information, and the region has a humidity index of 20-30, having the aqueduct capacity index of 45-60. In this research these features had the most weights of evidence and there for criticality. Evaluating the model was accomplished by using the roc model curres, and also the precision of the probability model which was obtained from the region was measured very well. (in was a good measurement of 76/51 percents).The research results present that the most important and effective factors on the region slope instability are the lithology factor, the distance from the fracture and the humidity index.