芦山地震重灾区崩塌滑坡易发性评价

Rockfall and Landside Susceptibility Assessment in Lushan Earthquake Region

2013-04-20 T08:02,四川省芦山县发生7.0级大地震,地震诱发了大量的次生山地灾害。在芦山、宝兴、天全三个地震重灾县6 651.35 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1 379处崩塌(含落石)滑坡。应用GIS技术,建立了芦山地震诱发崩塌滑坡灾害及相关地形、地质空间数据库,分析了岩性、断层、地震动加速度、高程、坡度等5个因素与崩塌滑坡分布的关系,应用崩塌滑坡数量百分比这一标准来分别衡量每个因素中各个级别对崩塌滑坡的影响程度;然后使用层次分析法对这5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,以此将研究区内的崩塌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4类,极高易发区与高易发区面积约2 149.89 km2,占研究区总面积的32.32%。

On 20 April 2013 ,a catastrophic Ms 7.0 earthquake struck Lushan, Ya＇ an, Sichuan Province of China. A great number of secondary mountain disasters whose main types include rockfall, landslide, rolling stone, dammed lake etc. had been induced by the earthquake. Not merely did these secondary disasters result in heavy casualties but also blocked road for rescue service, which retarded the relieving progress. 1 379 and landslides rock- fall were interpreted from aerial photographs and muhi-source remote sensing imageries, verified by field check. A spatial database,including rockfall（landslide） and associated controlling parameters which may have influence on the occurrence of rockfall （landslide） , was developed and analyzed using geographical information system （GIS） technology. The correlations of rockfall （landslide） distribution with controlling parameters, including faults, litholo- gy, elevation, slope angle, PGA were firstly analyzed, and landslide number-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 rockfall（landslide） The resulting susceptibility map showed five classes of rockfall （landslide） susceptibility, i. e. extremely high, high, moderate, low. The area with extremely high and high susceptibility accounts for about 2 149.89 km2 ,32.32% of the study area.