Comparison Of Geological Hazard Zoning Methods

Geological hazard zoning is one of the main tasks of geological hazard analysis and evaluation.At present,there are various methods for zoning the risk of geological disasters.What kind of evaluation method zoning results are more reasonable,and the differences in the results of different evaluations are still inconclusive.Taking the Suichang-Zhouqu section of the Bailong River basin,one of the most developed areas of geological disasters in China,as an example,the most widely used extension model,fuzzy comprehensive model,binary logistic regression model,and set pair analysis method are adopted.The grid unit and the basin unit respectively quantify the landslide,collapse disaster and debris flow hazard risk.By comparing the evaluation results obtained by the three methods,the advantages and disadvantages of each model method and the applicable conditions are analyzed,and then the relative optimal division method is proposed.The study area was selected in the Baichang River Basin of Gansu Province-the Suichang-Zhouqu section,which is one of the high-risk areas in China.For the grid unit and the basin unit,select the elevation,slope direction,slope,lithology,distance from the main trunk and the distance between the road and the road,and the area of the basin,the source of the unit area,the vertical ratio drop,the 24 h rainfall,There are five indicators of the basin completeness coefficient.Based on the grey correlation degree and entropy method,the evaluation factor weights are determined together.With the help of MATLAB and SPSS software,the geological disaster risk assessment tool is constructed and the evaluation results are presented on the GIS platform.The Bailong River in the study area is divided into the upper and lower reaches of the two rivers of Suichang County in the study area,namely the junction of the Minjiang River and the Bailong River.The evaluation results show that the risk of landslide and collapse in the upper reaches of Bailong River in the study area is higher than that in the lower reaches,and the risk of landslide and collapse on the left bank of Bailong River is lower than that on the right bank.In the basin unit,the risk of the upper reaches of the Bailong River in the study area is higher than that in the downstream,in Bailongjiang.In the comparison between the left and right banks,the risk of the right bank of the Bailong River is lower than that of the left bank.Different methods have also shown certain differences in geological hazard zoning: landslides and collapse disasters: the area of the lightly dangerous area of the logistic regression model is almost zero,and most of the areas are moderately dangerous areas;fuzzy synthesis The evaluation and evaluation results are relatively reasonable;the results of the matter-element extension model still show a large area of mild danger zone in the Zhongshan area on the left bank of the Bailong River,which is inconsistent with the field investigation;the evaluation result of the analysis method of the risk division of the debris flow disaster Obviously,the results of the survey are quite different from those of the field survey.The results of the evaluation of the matter extension model are moderately dangerous for the two mudslides in Huamagou and Shijizigou.This is different from the field survey results;fuzzy comprehensive evaluation results It has the highest agreement with the field survey results.The verification of the zoning results mainly uses the actual geological hazard data and the ROC(trainee operating characteristic curve).The results show that in the evaluation of landslide and collapse disasters,the AUC(Area under ROC Curve)values of the fuzzy comprehensive evaluation method,the provenance extension model and the logistic regression model are 0.90,0.75,and 0.53,respectively.In the evaluation of debris flow hazard,fuzzy comprehensive evaluation,The AUC values of the matter-element extension model and the set pair analysis method are 0.98,0.96,and 0.80,respectively.In summary,the fuzzy comprehensive evaluation methods are more suitable for the geological hazard zoning of this segment.