Risk Assessment Of Landslide In Shimen County Based On GIS

Shimen county is located in the northwest of Hunan Province.The mountain area accounts for 71.8% of the total area of the county.Complex geological conditions provide a favorable environment for the development of geological disasters,especially landslides.It is of great practical significance to effectively reduce the casualties and property losses caused by the landslide geological disasters in Shimen county.Based on field investigation and data collection in the field,230 landslide geological disasters in Shimen county are taken as research objects in this paper.Remote sensing image interpretation,fractal theory,information volume method,combination weighting method and ArcGIS software are used to study the landslide geological disasters in Shimen county.The risk assessment and zoning of regional landslide geological disasters,the main results are as follows:(1)Based on fractal theory,the relationship between landslides and influencing factors is studied.Spatial distribution of landslide with slope,elevation,engineering geological rocks and vegetation of landslides show a second-order cumulative total fractal distribution,while other factors such as aspect,fault structure,river buffer,rainfall,human engineering activities and landslides is in first-order cumulative total fractal distribution.These demonstrate the quantitative relationship between the occurrence of landslides and various impact factors from the perspective of fractal.If it shows a second-order cumulative total fractal relationship,it shows that the factor ihas great influence on landslide development.Through the analysis of the pregnant environment in the study area,it is found that the relationship between the spatial distribution of landslide and slope,aspect,elevation,engineering geology and rock mass and other factors is corresponding to the sensitivity obtained by the variable dimension fractal theory.It shows that the fractal dimension of fractured landslide is feasible and reliable,and it can quantitatively reflect the spatial relationship between the landslide and the various influencing factors.(2)Based on the fractal theory,a risk zoning study was carried out.In this paper,230 landslide geological disasters in Shimen county are taken as research objects in this paper.It is proved that they are in accordance with the distribution of fractal clusters,and the zoning map of danger is obtained.The result of zoning map basically meets the actual situation.This method can quickly get the zoning maps of the study area in the absence of geological elements and has certain application value.(3)Based on the amount of information,a risk zoning study is carried out.In the case of various geological factors such as slope,lithology,rainfall,and human engineering activities,the zoning map of the area is obtained,and the zoning results are more in line with the objective reality.(4)According to population density,arable land density,woodland density,construction land density and road density,the vulnerability assessment index system of landslide geological disasters in Shimen County is established.Through supervised classification to the Landsat5 TM remote sensing image by ERDAS IMAGINE remote sensing software,the present situation of land use in Shimen County was obtained.Using the spatial analysis function of ArcGIS software to complete the analysis of the evaluation factor.The results show that the vulnerability of landslide geological disasters in Shimen county is generally high in the south and low in the north.(5)According to the quantitative expression of risk(degree of risk = degree of risk × vulnerability),we use ArcGIS's grid calculator to multiply the re-classified hazard and vulnerability raster layers to get the assignment risk Layers.Then useing of natural breakpoint method,we can obtain the study area risk zoning map.It is found that the areas with high risk of landslide geological disasters in Shimen county are scattered,mainly distributed in Xinguan town,Yijiadu town,southern Xinpu town,Nanbei town,Hupingshan town and Saijie township.