证据权法在滑坡危险度区划研究中的应用

采用证据权法对长江三峡库区秭归--巴东段进行了滑坡危险度区划研究。数据源主要包括地质图、SPOT5多光谱卫星影像数据及数字高程模型(DEM)等。利用RS和GIS的数据提取和分析功能,分别提取了地质(岩性和构造)、地形(坡度、坡向、水系、高程、沟壑缓冲区、沟壑密度)、水文地质(植被指数)和破坏动力(河流缓冲区)等对研究区滑坡发育影响较大的影响因子的信息。将上述各种影响因子进行分级,建立若干证据层;然后根据已知滑坡在不同证据层中的分布,确定相应证据层的权重值;最后根据不同影响因子权重值的叠加来确定具体某一个单元滑坡发育的概率。分析结果与现有滑坡的分布情况比较吻合。采用证据权法可以客观定量地评价各种影响因子对滑坡发育的影响程度,并据此进行滑坡危险度评价因子(证据因子)的选择及危险度定量评价。

Zonation of landslide hazards based on weights of evidence model

The weights of evidence model was applied to study the zonation of the landslide hazards in the study area from Badong county to Zigui county in TGP reservoir region.The causative factors involves types and structure of rock(lithology,fault),landform(aspect,slope,elevation and drainage network),hydrogeological conditions(NDVI) and dynamic factors(distance to river),which were derived from geological maps,spot image data and digital elevation model(DEM) based on RS and GIS technology.The zonation of the landslide hazards was analyzed using weights of evidence model.Based on the frequency of known landslides in the classes of causative parameters,weight values were assigned to classify parameters,then the zonation map of landslide hazards was produced by summation of assigned weight values.The obtained results were well coincident with the occurrence of the known landslides in the study area,indicating that the weights of evidence model could choose the main factors and could be calculated well and objectively.So the methodology was very useful and accurate,and the approach was appropriate for the zonation of the landslide hazards.