The Risk Evaluation Study On The Geological Hazards In Leibo County Based On GIS

Leibo County belongs to Liangshan Yi Autonomous Prefecture,It is located in the southwest edge of Sichuan Province,the north bank of the lower reaches of the Jinsha River,the Sichuan Basin and the transitional zone of the Yunnan-Guizhou Plateau.It is a typical mountainous county,including Landslides,debris flow,collapse,unstable slopes and other geological disasters,which affect the people's life and property securit.The evaluation of geological hazard risk not only includes the content of hazard assessment,but also includes the contents of vulnerability assessment and disaster resistance assessment,which has the great theoretical and practical significance for the prevention and control of geological disasters.This article takes Leibo County as the research target.Based on the investigation of geological hazards in the field and the collection of the relevant data,the risk assessment model of the area is identified,namely,risk = hazard×vulnerability/disaster prevention ability.First,the geological hazard assessment has carried out.The grid subdivision unit was used to evaluate the geological hazard of Leibo County by using the analytic hierarchy process and the fuzzy comprehensive evaluation method.Secondly,using the township as the research unit,with the AHP and grey clustering comprehensive to evaluate the geological vulnerability disaster in the study area.The mathematical model of the disaster resistance assessment was established by expert scoring and the evaluation of the disaster resistance of the geological disaster was completed.Finally,based on the completion of the those assessments,using the superposition analysis function of GIS software to complete the risk geological disasters assessment in Leibo County.Based on the risk evaluation results of the Leibo County,the paper puts forward some reasonable suggestions for the prevention geological disasters.The main results of this study are as follows:(1)The main types of geological hazards in the study area are landslides,debris flows,collapses,unstable slopes and bank collapse,Which including the landslide 141,41.35% of the all quantity,debris flow 81,24.34% of the all quantity,collapsed 74,21.7% of the all quantity,unstable slope 31,9.09% of the all quantity,bank collapse 12,accounting for 3.52% of of the all quantity.(2)In the case of clarifying the geological conditions on the study area,the hazard evaluation system is constructed from three aspects: basic factors,predisposing factors and disaster history.Based on the fuzzy comprehensive evaluation model,the trapezoidal membership function is established by using yahhp software,and the fuzzy comprehensive evaluation matrix is constructed.Lastly,the county is consist of high-medium-low risk regions.(3)Based on the investigation of the social and economic development of Leibo County,the vulnerability assessment system was constructed from the aspects of population vulnerability,material economy vulnerability and vulnerability of resources and environment.According to the gray clustering comprehensive evaluation model,the whitening weight function is established,and the gray number of the evaluation unit is determined.And then the county is consist of high-medium-low vulnerability regions.(4)According to the actual situation,the warning monitoring points and the fiscal revenue evaluation index are selected.According to the mathematical model,the disaster prevention ability is finished.Based on the hazard evaluation area,vulnerability area and disaster prevention area,which are finished,using the function of GIS about the spatial overlay and analysis function to finish the final risk evaluation on the Leibo county.Combined with the hazard area and risk area,the paper puts forward some suggestions for preventing the geological hazards.