The Risk Zoning Of Geological Disaster In Shangzhou County, Shangluo

Shangzhou is located in the central section of Shangluo. It is in the hinderland of Qinling Mountain and the intense tectonic activities in the area result in the special geological environment of Shangzhou, which also provides favorable conditions for the frequent occurrence of geological disasters. This paper chooses Shangzhou in Shangluo as the studied area. Based on the survey data in Shanxi Geological Survey Institute and the collected basic geological data, and according to the analysis of the data, it gets hold of the general development situation of the disaster and selects four types of influencing factors that contribute much to the risks, namely the current situation of the disaster, geological environment, precipitating factors and the degree of human activities. Then it further analyzes nine evaluation factor in detail, namely density of the disaster places, stability of the disaster points, geomorphic type, rock-soil mass, density of fracture, distribution of rivers, precipitation, population density and road density, and establishes the risk evaluation index system. It adopts the analytic hierarchy process that considers the expert level to determine the comprehensive weight of the evaluation factors, and builds the evaluation model based on GIS and AHP, thus realizing the risk zoning of the geological disaster in Shangzhou. The main research achievements are as follows:1 The number of various geological disaster places developed in Shangzhou amounts to 185, including 164 places of landslide, 13 places of collapse, 6 places of debris flow and 2 places of ground subsidence. The proportions of various disaster are respectively: 89%, 7%, 3%, 1%.2 The disasters developed in Shangzhou present a certain regularity in the distribution of time and space. In terms of time, they concentrate in the period of human activities and during the rainy season; in space, they present concentrated growth in river valley of the mountainous areas and hilly areas, and they also develop intensively in the tectonic zone of “three fault and two basin”.3 Aimed at the defects of the traditional AHP, it puts forward the analytic hierarchy process that considers the expert level; it builds the construction matrix based on the different expert levels and by virtue of the software of Matlab, it calculates maximum eigenvalue of the construction matrix and the eigenvector, then the paper determines the weights of each evaluation factor. The results are respectively as follows:0.133, 0.266, 0.032, 0.033, 0.0086, 0.0094, 0.119, 0.2, 0.199.4 This paper proposes the risk evaluation model of the geological disaster in Shangzhou based on GIS and AHP, draws the risk degree zoning map. The evaluation results divide Shangzhou into high-risk area, medium-risk area, low-risk area and non-risk area, and they respectively account for 5.42%, 40.99%, 51.28%, 2.31% of the total area.