Ningqiang County Geological Disaster Risk Assessment

The Hanzhong Ningqiang County in Shaanxi Province was seriously affected by the Wenchuan earthquake in 2008,which caused serious impact on the geological environment of the area,and the risk of geological hazard of the residents in the area increased obviously.In order to make the post-earthquake reconstruction and economic and social development is more scientific and reasonable.Reducing the harm of geological hazards to people.The paper mainly relies on the investigation and zoning report of geological disasters in Ningqiang county of Hanzhong city,Shaanxi province.Through field investigation,combined with relevant data,the development characteristics and distribution of geological disasters in the study area are analyzed.Make use of fuzzy comprehensive evaluation method,risk assessment,and then using grid computing function of ArcGIS to study area,it is concluded that the study area risk zoning maps.Finally,it is concluded that risk assessment results in the study area.The main research results are as follows:1.The study area is mainly developed landslide,collapse,debris flow and ground subsidence of these four geological disasters.Landslide is the main disaster.The total geological hazard points are 241.Landslide points are 211.collapse points are 15.debris flow points are 11.Ground collapsed points are 4.2.The seven main risk assessment indexes of geological hazard point density,slope degree,slope type,engineering geological rock group,geological structure,rainfall and human engineering activities were selected.And the evaluation results were divided into three grades:low,medium and high risk.The area of the grading area is about 755km~2,1767km~2,724km~2 respectively.3.Risk zones for geological hazards are made in the study area.The high risk area is about 533km~2,the area of the higher risk zone is about 783km~2,the middle risk area is about993km~2,the lower risk area is about 531km~2,and the area of low risk area is about 406km~2.This topic research is the basis of the studying of the earthquake geological disaster preventive measures in earthquake area.The geological hazard risk zoning map of the earthquake disaster area in this study has important guiding effect on the geological disaster risk assessment,disaster prevention and mitigation and disaster restoration and reconstruction in each district and county.