Study On Risk Assessment Of Landslide Hazard In Zhaotong

Zhaotong City is located in the northeastern part of Yunnan,with strong tectonic activities,complex stratum lithology,and fragile surface environment.It is one of the frequent occurrence areas of landslide geological disasters in Yunnan Province.Based on high-resolution remote sensing satellite data,this paper has basically found out the spatial distribution characteristics of landslide geological hazards in Zhaotong City and conducted field investigation and verification of the interpretation results,and established a spatial database of landslide geological hazards in Zhaotong City.Based on this,the quantitative characteristics,scale characteristics,density characteristics,landslide material composition and formation conditions of Zhaotong landslides are analyzed and summarized,and the relevant indicators of Zhaotong landslide risk evaluation are selected and classified.At the same time,correlation analysis was carried out,and independent index factors were selected for landslide risk assessment.Finally,the probability coefficient model(CF)and logistic regression model(LR)are used to evaluate the risk of landslide geological hazards in Zhaotong City,and the evaluation results of the combined model are analyzed and discussed in combination with the actual situation,which better reveals The distribution characteristics of landslides in Zhaotong City,Yunnan and provide reference for its prevention and control.This article has mainly achieved the following results and understandings:(1)The spatial distribution of landslide geological disasters in Zhaotong City has been basically investigated,and a database of landslide geological disasters in Zhaotong City has been established.(2)The development characteristics and formation conditions of the landslide in Zhaotong City are revealed.The development characteristics of landslide geological hazards in Zhaotong City are discussed from the quantitative characteristics,scale characteristics,density characteristics and landslide material composition.The formation of landslides in Zhaotong City is related to many factors such as the terrain,structural fault zones,lithology,climate,and human activities.(3)Established a landslide risk evaluation system applicable to Zhaotong City.Based on the formation conditions of landslide geological disasters in Zhaotong City,a total of 9 landslide hazards including elevation,rock hardness,normalized vegetation index(NDVI),slope,distance from the river,rainfall,aspect,distance from the fracture,and distance from the road were selected.Evaluation indicators,and then quantitatively classify each evaluation index and analyze and discuss the classification results.At the same time,the correlation analysis between evaluation indexes is carried out to ensure the independence of evaluation indexes.The results show that the independence of the evaluation indexes is high,and all 9 indexes can be used in the evaluation model.(4)Based on the CF?LR combined model,the risk assessment and zoning of landslide geological disasters in Zhaotong City were carried out.After the evaluation unit and evaluation index are determined,the CF value of each grading range of each evaluation index is calculated and analyzed,and then a logistic regression model is established to calculate the risk of landslide geological disasters in Zhaotong City,and the risk calculation results are calculated according to the equal interval method.It is divided into four levels: low-risk zone(?),medium-risk zone(?),high-risk zone(?),and extremely high-risk zone(?).(5)Verify and analyze the results of the risk assessment.From the rationality test,the evaluation result based on the CF?LR combination model is basically reasonable.From the accuracy test,the receiver operating characteristic curve(receiver operating characteristic curve,referred to as ROC curve)of the evaluation result shows that the AUC value is 0.765,which is in Between 0.7 and 0.9,it shows that Zhaotong City's risk assessment results based on the CF?LR combined model are more accurate.At the same time,a comprehensive analysis of the evaluation results was carried out based on the actual situation.