GIS支持下基于层次分析法的汶川地震区滑坡易发性评价

 2008年5月12日14时28分，四川汶川发生了Ms8.0级大地震，地震诱发了数以万计的滑坡灾害。在大约48 678 km2的区域内，采用震后遥感影像解译并结合野外调查的方法，共解译出48 007个滑坡。应用GIS技术，建立了汶川地震诱发滑坡灾害及相关地形、地质空间数据库，分析了断层、岩性、高程、坡度、坡向、河流、公路等7个因素与滑坡分布的关系，应用滑坡面积百分比这一标准来分别衡量每个因素中各个级别对滑坡的影响程度；然后使用层次分析法对这7个参数进行权重分析；在GIS平台下对这些参数进行综合分析，通过分析结果将研究区内滑坡按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约8 211 km2，占研究区总面积的16.9%；最后，使用汶川地震滑坡数据库对研究结果进行检验，检验曲线表明分区效果良好，其中极高易发区与高易发区内实际发生滑坡面积为430 km2，占滑坡总面积的60.5%。

GIS-BASED LANDSLIDE SUSCEPTIBILITY ASSESSMENT USING ANALYTICAL HIERARCHY PROCESS IN WENCHUAN EARTHQUAKE REGION

On 12 May 2008,a catastrophic earthquake with surface wave magnitude of 8.0 struck the Sichuan Province of China. Tens of thousand of landslides were triggered by this earthquake over a broad area. 48 007 landslides were interpreted from aerial photographs and multi-source remote sensing imageries,verified by field check. A spatial database,including landslides and associated controlling parameters which may have influence on the occurrence of landslides,was developed and analyzed using geographical information system(GIS) technology. The correlations of landslide distribution with controlling parameters,including faults,lithology,elevation,slope angle,slope aspect,drainages and roads are firstly analyzed,and landslide area-ratio was calculated for each group of the above parameters. An analytical hierarchy process(AHP) was then applied to determine the significance of controlling parameters in triggering the landslides. The resulting susceptibility map showed five classes of landslide susceptibility,i.e. extremely high,high,moderate,low,and extremely low. The area with extremely high and high susceptibility accounts for about 8 211 km~2,16.9% of the study area. This indicates that the result is reasonable in 60.5% of the landslides occurred in high or extremely high susceptibility region.