基于证据权法的巴东县城滑坡灾害易发性评价

巴东县城由于其特殊的地理位置和特有的地质条件,使之成为滑坡灾害多发地带,严重威胁着巴东县城的发展,因此,有必要对巴东县城进行滑坡易发性评价研究。首先,基于GIS平台分别提取影响滑坡发生发育的各指标因子(地层岩性、地形地貌、地质构造、水文地质条件等),并划分证据层;其次,采用证据权法分别计算各证据层的权重及后验概率;然后将单元各证据层后验概率进行叠加,生成滑坡易发性分区图;最后,使用自然断点法将研究区按滑坡易发程度分为极高易发区、高易发区、中易发区、低易发区与极低易发区5类,极高易发区与高易发区面积之和约占研究区总面积的33%,其中86%的已有滑坡发生在极高易发区和高易发区,利用成功率曲线检验表明区划效果较好。

Landslide susceptibility evaluation in Badong County based on weights of evidence method

Because of its special geographical location and special geological conditions, Badong County becomes a prone zone of geological hazards, especially landslide disasters. It is necessary to research landslide susceptibility evaluation, because of its serious threat to the development of Badong County.First, we extracted the influence factors of the formation and development of landslide respectively and divided the evidence layer on GIS.The influence factors include the formation lithology, geographic and geomorphic conditions, geological structure, and hydrogeological conditions.The weights of evidence method was applied to calculate the weights of each layer of evidence and posterior probability respectively.Then, distribution chart of landslide susceptibility was generated by overlaying posterior probability of evidence layer of each unit. Finally, according to Natural Breaks law, the researched region was divided into five categories:extremely high, high, moderate, low, and extremely low by landslide susceptibility.The sum area of extremely high and high is about 33% of the total area and about 86% of existing landslides occurred in extremely high prone area and high prone area.The result shows good by using the success rate curve test that division.