基于危险源识别的山区地质灾害风险定量评价——以贵州省茅台镇为例

Quantitative Risk Assessment of Geological Hazards Based on Hazard Source Identification——A Case Study of Maotai Town,Guizhou Province

我国西南山区是地质灾害多发易发地,特别是贵州省西北部近四川盆地的盆山过渡带,滑坡和崩塌对居民生产和生活构成了严重威胁。为合理预测山区地质灾害风险的空间分布特征,以贵州省茅台镇为研究区,开展了山区乡镇尺度地质灾害风险评价的探索性研究。应用层次分析法,以水文斜坡单元为基础评价单元,对研究区地质灾害易发性、危险性、易损性和风险进行了量化,并通过划分地质灾害易发性临界阈值识别地质灾害相关危险源,分析其运动特征和影响范围,建立了一套适合山区的地质灾害危险源识别及run-out定量分析方法,并据此对斜坡单元的风险评价结果进行修正。结果表明:斜坡坡度、工程地质岩组和斜坡变形是研究区地质灾害发育的主要控制因素;研究区地质灾害空间预测准确率为92%,ROC曲线的AUC值为0.97;结合危险源影响范围预测和风险分析,确定研究区赤水河两岸及北部山区人口伤亡风险和建筑物财产损失风险较高,而茅台镇北部罗村及柏杨村一带的丘陵地区人口伤亡风险和建筑物财产损失风险较低。本研究提出的危险源分析手段和地质灾害定量风险评价方法适用于盆山地带乡镇尺度的地质灾害风险评价,可为国土空间规划和地质灾害应急决策提供必要的资料和参考。

The mountainous areas in southwest China are prone to geological disasters,especially the basin mountain transition zone near the Sichuan Basin in the northwest of Guizhou Province.In this area,land-slides and rock fall pose a serious threat to the residents.To reasonably predict the spatial distribution characteristics of geological hazards in mountainous areas,an exploratory study on the township scale was carried out in Maotai Town,Guizhou Province.The analytic hierarchy process were applied to quantify the susceptibility,hazard,vulnerability and risk value of geological hazards in Maotai Town in the hydrological slope unit.Meanwhile,the hazard sources were identified concerning the susceptibility threshold,and the kinematic features and influence area of each source were analysed to establish a set of identification and run-out quantitative analysis method for hazard source of geological hazards suitable for mountaineous are-a,which was used to modify the risk evaluaiton results.The results show that the slope gradient,engineer-ing geological rock group and slope deformation features are the main factors that guarantee the stability of the slope in the study area.The accuracy of landslide susceptibility mapping reaches 92% with a AUC value of ROC curve being O.97.Combined with the run-out analysis of the hazard sources and the further risk as-sessment,it can be seen that the risk of casualties and buildings property loss is high on both banks of the Chishui River and the northern mountain areas,while the hilly areas around Luo Village and Baiyang Vil-lage in the north of Maotai Town are of low risk.The framework of risk assessment and hazard source a-nalysis method in this research can provide a necessary reference for land space planning and the decision-making of disaster emergencies.