基于AHP-LR熵组合模型的子长市地质灾害危险性评价

Risk Assessment of Geological Hazards in Zichang County Based on AHP-LR Entropy Combined Model

延安市子长市是地质灾害较为严重的地区,受地形地貌、地质环境条件、人类工程活动等诸多因素的影响,尤其是在强降雨气候下,区内崩塌、滑坡等地质灾害时有发生,严重威胁着人们的生命和财产安全。为了对研究区地质灾害危险性进行综合评价,建立了年均降雨量、道路距离、坡度、土地利用类型、岩土体类型等9个评价指标,利用层次分析法(analytic hierarchy process,AHP)与逻辑回归法(logistic regression,LR)的熵组合模型求得的各类评价因子权重值乘以对应因子层中的信息量值,在ArcGIS平台中对各类评价因子栅格图层进行了叠加分级处理并对评价结果采用受试者工作特征(receiver operating characteristic,ROC)曲线进行精度检验。结果表明,基于AHP-LR熵组合模型下的危险性评价结果准确率达到0.897,明显高于单一赋权模型的精度。区内极高、高危险性分级主要集中于研究区中部,两类分区下的面积为352.49 km^(2),约占全区总面积的15%。研究成果可为该区的防灾减灾工作提供一定参考,同时对同类地区的地质灾害危险性评价也具有一定借鉴意义。

Zichang City of Yan'an City is a relatively serious area of geological disasters.With the influence of topography and landforms,geological environment,human activities and other factors,geological hazards such as landslide and collapse occur in this area from time to time especially in the climate of heavy rainfall and the safety of people's lives and properties are seriously threatened.In order to make a comprehensive evaluation of the geological hazards risk in the study area,nine evaluation were established that including average annual rainfall,road distance,slope,land use type,and geotechnical type were established.The weight values of various evaluation factors obtained by using the entropy combination model of analytic hierarchy process(AHP)and logistic regression(LR)were multiplied by the value of information in the corresponding factor layer.The evaluation factor raster layers were overlaid and graded in ArcGIS platform and the evaluation results were checked by receiver operating characteristic curves for accuracy.The result shows that the accuracy rating of the combined AHP-LR entropy model is 0.897,which is significantly higher than the accuracy of the single-assignment model.The extremely high and high risk classification in the area is mainly concentrated in the central part of the study area.The area under the two types of zoning is 352.49 km^(2),accounting for about 15%of the total area of the district.The research results can provide some reference for the disaster prevention and mitigation work in the district.It also has some significance for the evaluation of geological hazard in similar areas.