基于GDIV模型的大渡河中游地区滑坡危险性评价与区划

Landslide hazard assessment in the middle reach area of the Dadu River based on the GDIV model

区域地质灾害评价是减灾防治的重要非工程手段,构建区域滑坡危险性评价模型,对提高地质灾害评价精度和防治效率具有重要意义。文章以滑坡频发的大渡河中游地区为研究区,初选高程、坡度、坡向、地震动参数、土壤类型、工程地质岩组、年平均降雨量和地形湿度指数(TWI)等13个因子,建立滑坡危险性初级评价指标体系。考虑各因子对滑坡形成贡献程度的不同和目前常权栅格叠加方式对滑坡危险性评价结果精度的影响,引入了地理探测器和变权栅格叠加,构建了地理探测器、信息量法和变权栅格叠加的组合模型(GDIV模型)。基于2021年四川省1∶50000地质灾害风险调查中313处滑坡地质灾害隐患点,开展基于GDIV模型的大渡河中游地区滑坡危险性评价,并与逻辑回归模型和信息量模型的组合模型(LRI模型)评价结果进行对比分析。结果表明:研究区以中危险及以下危险区为主,占总面积的78.3%,极高和高危险区主要分布在大渡河、革什扎河和东谷河两岸的低海拔地区;与LRI模型相比,基于GDIV模型的评价结果精度更高,其受试者工作特征(ROC)曲线的线下面积(AUC)值为0.917。文章提出的GDIV模型提高了区域滑坡危险性评价精度,可为类似地区地质灾害评价提供方法参考。

Regional geological hazard assessment is an important non-engineering approach for disaster reduction and prevention.Constructing a regional landslide hazard assessment model is of great significance in improving the accuracy of geological hazard evaluation and the efficiency of prevention.This study focuses on the frequent landslide occurrence in the middle reach area of the Dadu River and selects 13 primary factors,including elevation,slope,aspect,seismic parameters,soil type,engineering geological lithology,annual average rainfall,and topographic wetness index(TWI),to establish a primary evaluation index system for landslide hazard.Considering the varying contributions of each factor to landslide formation and the impact of the commonly used weighted raster superposition methods on assessment accuracy,the geographic detector and variable weight raster overlay techniques are introduced,leading to the development of the GDIV model.Using data from 313 landslide hazard points identified in the 2021 geological hazard risk survey at a scale of 1∶50,000 in Sichuan Province,the landslide hazard assessment in the middle reach area of the Dadu River basin is conducted based on the GDIV model,and the evaluation results are compared with those of the LRI model.The results show that the study area is predominantly characterized by middle and lower risk areas,accounting for 78.3%of the total area.The extremely high and high-risk areas are primarily located in the low-elevation regions along the banks of Dadu River,Geshizha River,and Donggu River.Compared to the LRI model,the evaluation results based on the GDIV model exhibit higher accuracy,with an area under the receiver operating characteristics(ROC)curve of 0.917.The GDIV model proposed in this paper improves the accuracy of regional Landslide hazards assessment,and serves as a valuable reference for similar geological disaster evaluations in other areas.