GIS支持下基于AHP方法的2013年芦山地震区滑坡危险性评价

GIS-based Landslide Hazard Evaluation Using AHP Method in the 2013 Lushan Earthquake Region

在详细综述国内外有关滑坡危险性评价研究进展的基础上,选取芦山7.0级地震区一个大致以震中为中心的100 km×100 km正方形区域作为研究区域,以GIS技术作为操作平台,确定地震滑坡影响因子,结合芦山地震滑坡特征将滑坡影响因子分级,分析高程、坡度、坡向、斜坡曲率、地层岩性和PGA等6个影响因子经分级概化后所代表的区域与滑坡的分布关系,采用区域分布面积百分比指标与滑坡密度指标来衡量影响滑坡的各个影响因子分级所代表的研究区间对地震滑坡影响程度;其次,使用AHP法对研究区内地震滑坡建立6个影响因子两两比较的6个关系矩阵,对6个关系矩阵分别进行各个参数权重的综合分析,所形成的影响因子权重分布曲线分析结果显示:地面峰值加速度PGA是影响地震滑坡最严重的因子,影响因子对芦山地震区滑坡影响程度关系为PGA>地层岩性>坡度>高程>斜坡曲率>坡向;取6组数据的平均值作为最终所确定的影响因子权重,以构建研究区内滑坡危险度阈值栅格图,接着将滑坡危险性阈值栅格图划分为与评价因子分级赋值时对应的极高危险区、高危险区、中危险区、低危险区和极低危险区,同时给出研究区滑坡危险性分区图。最后,根据芦山地震实际所触发的滑坡构建滑坡易发性评价结果检验曲线验证评价结果的合理性,验证结果表明:AUC值为85.41%,即定量衡量滑坡评价结果的准确率为85.41%,表明评价结果准确率较高。

Based on the detailed review on the basis of domestic and foreign research progress on landslide hazard evaluation,the paper selected a great extend square area of 100 km ×100 km that centered around the epi-center as the study area in Lushan earthquake region.With GIS technology as a platform and combined with the feature of Lushan earthquake determined earthquake landslide impact factors for classification;analyzing the rela-tionship between the represented area after a generalized assignment of the six impact factors on elevation,slope, aspect,curvature,lithology,and PGA after the distribution of landslides;zonal area percentage and landslide den-sity index was used to measure the influence degree of various influence factors from earthquake landslide.Second-ly,Using the method of AHP set up six relation matrix by six impact factors comparing the two for comprehensive analyzing each parameter weight;the influence factor weight distribution curve analysis results showed that PGA is the most serious factor affecting earthquake landslide and PGA 〉lithology 〉slope 〉elevation 〉curvature 〉aspect is a relationship of impact factor to measure the influence degree of landslide Lushan earthquake region;Taking the average of six sets data as the final factor weight to build the landslide hazard threshold grid graph in the study area,and then dividing landslide hazard threshold grid graph into extremely high hazard zone,high hazard zone,middle hazard zone,low hazard zone,extremely low hazard zone which correspond the classification and as-signment of evaluation factor;simultaneously,landslide hazard zoning map of the study area was provided.Finally, the rationality of the evaluation results was verified according to the landslide hazard evaluation results test curve of the actual triggered by Lushan earthquake landslide;Verification results showed that the value of AUC is percent 85.41 ,the accuracy of quantitative measure of landslide evaluation result for percent 85.41 implied that the evalua-tion results accuracy is higher.