基于GIS的云南省施甸县地质灾害风险综合评估

Comprehensive assessment of geological disaster risk based on GIS in Shidian County,Yunnan

云南省施甸县地形地貌复杂,构造活动强烈,地质环境条件脆弱,加上人类活动的不断扩大,导致滑坡、泥石流和崩塌等地质灾害频发.为了对施甸县地质灾害风险进行综合评估,以RS和GIS技术为支撑,选取7个孕灾稳定性因子、9个致灾危险性因子和5个脆弱性因子,分别从孕灾环境稳定性、致灾因子危险性、承灾体脆弱性3方面出发,采用信息量模型+逻辑回归模型(I+LR)和确定性系数模型+逻辑回归模型(CF+LR)2种组合模型对施甸县孕灾环境稳定性进行评价;采用层次分析法(analytic hierarchy process,AHP)和最小二乘法(ordinary least squares,OLS)2种模型对施甸县致灾因子危险性进行评价;采用层次分析法(AHP)对施甸县承灾体脆弱性进行评价,并对施甸县地质灾害风险进行综合评估.结果表明:施甸县综合风险较高区多集中在县域中部地区,其中甸阳镇、仁和镇和由旺镇最为明显,施甸县约10%的区域属于孕灾环境动荡区,约5%的区域属于致灾因子极高危险区,约12%的区域属于承灾环境危险区.对比分析了多种综合模型的评价精度与适用性,发现信息量模型与确定性系数模型评价结果相差较小,均适用于孕灾环境稳定性评价,最小二乘法评价模型ROC曲线AUC值为0.756,略高于层次分析法.

Shidian County of Yunnan Province has complex terrains and landforms,strong tectonic activities,and fragile geological environment conditions.In addition,unreasonable human activities have led to frequentgeological disasters such as landslides,mudslides,and collapses.In this paper,RS and GIS technologies are usedas support in order to conduct a comprehensive assessment of geological disaster risks in Shidian County.Sevendisaster-prone stability factors,nine disaster-causing risk factors,and five vulnerability factors are selected tofirstly study the stability of the disaster environment,the risk of disaster-causing factors,and the vulnerability ofthe disaster bearing body.Then the stability of the disaster-prone environment in Shidian County is evaluated usinga combination of information quantity model plus logistic regression model(I+LR),and deterministic coefficientmodel plus logistic regression model(CF+LR).The risk of disaster-causing factors in Shidian County is evaluatedusing Analytic Hierarchy Process(AHP)and Ordinary Least Squares(OLS)models.The vulnerability of disaster-prone areas in Shidian County is evaluated using Analytic Hierarchy Process(AHP).And finally here is conducteda comprehensive assessment of the geological disaster risk in Shidian County.The results show that the areas withhigh comprehensive risk in Shidian County are mostly concentrated in the central region of the county,withDianyang Town,Renhe Town,and Youwang Town being the most obvious.About 10% of the areas in ShidianCounty are in an unstable disaster-prone environment;about 5% face extremely high risk factors for disasters;andabout 12%,high-risk environments for disasters.Meanwhile,a comparative analysis is conducted on the evaluationaccuracy and applicability of various comprehensive models,and it is found out that the difference between theevaluation results of the information quantity model and the certainty coefficient model is small,both of which aresuitable for evaluating the stability of the disaster-prone environment.The AUC value of the ROC curve of theleast squares method evaluation model is 0.756,which is slightly higher than that of the Analytic Hierarchy Process.