Research On Landslide Hazards Risk Assessment In Chuxiong City

Chuxiong City is located in the central and western part of Chuxiong Yi Autonomous Prefecture in Yunnan Province.The terrain is high in the west and low in east,and the geological environment is complex.Affected by the surrounding Sichuan-Chongqing and other major earthquakes(Wenchuan and Yushu),the geological disasters in the study area are frequent,which severely hindered and constrained local economic development.This article mainly relies on the detailed investigation project of geological disasters in Chuxiong City,Yunnan Province,and takes the distribution of landslide disasters in Chuxiong City as the research object.Based on the field geological disaster investigation data and the collected basic geological material,the impact of factors on landslide hazards such as the landform and geomorphology,geological structure,formation lithology and meteorological and hydrological are statistically analyzed,and using the theory of statistics to study the development characteristics and distribution characteristics of landslide disasters in the study area,the spatial distribution of landslide hazards was obtained.Combined with the geological environment of the study area,we selecte seven assessment factors such as relative elevation,slope,stratum formations,annual average rainfall,distance from faults,distance from water system,and distance from highway as landslide hazard risk assessment index system.Through the empirical formula and the grid size of the DEM data,the size of the evaluation cell is selected to be 30m×30m.The evaluation matrix in the hierarchical structure and the feature vector under the maximum eigenvalue are used to determine the weight of each evaluation factor.Based on the ArcGIS platform spatial analysis and overlay functions,the risk zoning evaluation of landslide hazards in Chuxiong City was conducted using the information volume method and the fuzzy comprehensive evaluation method respectively.We reclassified each map according to its own model to obtain high,medium,and low risk areas within the study area.The hazardous area,among which,the information model method results show that the area of landslide hazards in the study area is 904.44 km~2,accounting for20.40%of the total area of Chuxiong City;the area of the middle risk area is 1,938.84km~2,accounting for approximately 43.74%of the total area;The area of low-risk area is1589.72 km~2,accounting for 35.86%of the total area.The results of the fuzzy comprehensive evaluation model show that the area of high-risk landslide hazard in the study area is 1182.46 km~2,accounting for 26.67%of the total area of Chuxiong City;the area of middle-risk area is 2212.47 km~2,accounting for 49.91%of the total area;the low-risk area is 1038.07km~2,accounting for 23.42%of the total area.Finally,we compared the landslide hazard zoning maps of the two research areas,similarity analysis shows that the similarity of the two models is about 75.11%,which shows that the evaluation results are almost the same as the actual results,The middle and high risk areas in the information method contained 282 landslide disaster points,which accounted for 83.43%of the total landslide disaster points.The high and medium risk areas in the fuzzy comprehensive evaluation contained 312 landslide disaster points,accounting for 92.30%of the total landslide disaster points.which shows that the fuzzy comprehensive evaluation method is more suitable for studying the risk assessment of regional landslide hazards in Chuxiong City than the information method.