Urban Geological Hazard Assessment Method Based On GIS

Since the beginning of the 21 st century,with the development of human urban construction and the transformation of the natural environment,various kinds of geological disasters have occurred more and more frequently.In China's megacities,the population density and human activities are particularly intensive,and the losses caused by disasters are particularly significant,which poses a great challenge to the strategy of disaster prevention and reduction.The occurrence of the traditional engineering and disaster prevention and cure mechanism analysis,the prediction has not satisfy the growing demand for disaster prevention and mitigation,and urban geological disaster risk assessment has become the mainstream direction of geological hazard prevention and control work,it reflects the regional geological hazards assessment area the extent of the damage to human loss and possibilities,which will provide a scientific basis for urban disaster prevention and mitigation of the deployment work and guidance,has important theoretical significance and application space.This article through to the slope geological disasters of the evaluation of the key theory and technology method,were analyzed using information method and analytic hierarchy process(ahp),fuzzy mathematics theory in combination of evaluation methods of two kinds of liability system,expounds the process and steps of the evaluation.Made the high accuracy DEM based on the data collected by the graph,and analyze the cause of the shenzhen slope type of geological disasters,according to the cause to select certain impact factors as evaluation factors,using the GIS spatial analysis using the above two methods respectively evaluate shenzhen's liability.Further,combined with the density of population in shenzhen city,the area per capita GDP and the three factors of land use types from shenzhen to suffer disaster vulnerability,and the risk of slope disaster types and acceptable degree of regionalization.Based on the above research,the paper mainly achieved the following results:(1)Study of geological conditions,the engineering environment research of Shenzhen: mainly through detailed geological exploration data provided by Shenzhen geological survey and analyze the data of other researchers,the Shenzhen meteorological hydrology,topography,stratum lithology,geological structure in-depth understanding and detailed.(2)Selection of impact factor: according to the geological condition of Shenzhen and slope disasters development characteristics,selected the elevation,slope,engineering geological petrofabric,fault buffer,vegetation coverage,gully density,the density of artificial slope as the impact factor of slope class disasters and use GIS vector graphics functions respectively according to the existing data,vector quantization of each factor to get classification map of each influence factor.(3)Liability districts: respectively by(1)the amount of information and(2)the fuzzy evaluation method combined with analytic hierarchy process(ahp)to Shenzhen liability of slope type of geological hazard regionalization,discusses the application of two methods in the region slope geological disasters and the applicability of the liability.And through the GIS space calculation,we can get the vulnerable zoning map of the slope type geological hazard in Shenzhen.(4)Verify the better method for evaluating the liability: according to the coordinate information collected in assessing the 375 history of slope geological point class make history slope type of geological hazard point diagram,and the results of the two kinds of evaluation method with GIS spatial overlay verification calculation,to verify the accuracy of the two kinds of liability evaluation method.(5)The assessment of vulnerability: evaluation of selection of hazard-affected factor of land use type,the density of population density and per capita GDP,the expert scoring method to determine each factor and weight,and form a discriminant factor index value and weight list.Using GIS to vectorize the existing data to obtain the vulnerability map.(6)Risk districts: liability division and combination of these processes vulnerability zoning,adopting "the lowest feasible" in the field of safety engineering ALARP method,slope class according to the geological disaster risk events liability rating scores of P and class by slope disaster risk events when the affected area of vulnerability C score,slope type of geological hazard risk classification matrix is established.Using GIS to calculate the spatial superposition of the region's vulnerability and vulnerability,we can obtain the geological hazard zone map of the slope of Shenzhen.