Study On The Assessment Of Earthquake Geohazard Probability Of Yanjin In Yunnan Province Based On GIS

Located in the northeast of Yunnan Province,Yanjin County is characterized by the territory of high mountains and steep slopes,complex topography,intense neotectonic movement,folds,faults.The geological condition of Yanjin County is very bad,and it is affected by human activities,heavy rainfall and earthquake.Yanjin County,which is disaster areas with frequent geohazard,is the national geohazard prone county.Especially in recent years,with the further deterioration of the global climate,human engineering activities are becoming more and more frequent,and geohazard has a tendency to develop and spread.Geohazard has become a threat to the safety of people's lives,and it has become the most important factor that restricts the development of local economy.Therefore,it is of great significance to the susceptibility and probability assessment of geohazard in the region.Based on the extensive collection of data and the investigation of geohazard in Yanjin,the paper summarizes the laws of the occurrence and development of geohazard such as landslide and rockfall in Yanjin,and the earthquake activity in this area is studied.Based on the model of the evidence weight model and the seismic probability index model,this paper takes the ArcGIS as the platform to carry out the assessment of the susceptibility and probability of geohazard in Yanjin country.The paper gets the preliminary conclusion as follow:The main geohazard are small landslide and rockfall in Yanjin.In space,the geohazard in this area is mainly distributed near the valley on both sides of river,and its tributaries in Baishuijiang etc.In time,the geohazard in the region mainly occurred in the local rainy season.Influence of landslide and rockfall disaster factors are topography(slope and aspect),engineering geological group,tectonic activities,hydrological geology,inducing factors including rainfall and human engineering activities,seismic activities etc.On the platform of ArcGIS,the weight of evidence evaluation model,Model Builder automation of geohazard susceptibility evaluation system is established,and the susceptibility of geohazard is evaluatied in Yanjin,and the zoning of geohazard is evaluated in detail.The seismic data of Yanjin and its surrounding areas since 1965 has been collected.In this paper,the time,space and depth characteristics of seismic activity in Yanjin are analyzed,and the potential source areas of earthquake in Yanjin are discussed.On this basis,with the infinite slope model and pseudo static method,simplified on the basis of the Newmark method,we take the sliding body as a rigid body.With Newton's second law as the criterion to measure the risk of slope unit with critical acceleration slope units,the seismic model for preliminary assessment the probability of earthquake geohazard is evaluted in Yanjin.