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2008年5月12日汶川MW7.9地震触发了大量的滑坡。基于地理信息系统和遥感技术,建立了一个详细完整的汶川地震滑坡编目图。该编目图显示,汶川地震中滑坡主要分布在约110 000km2的区域内,滑坡的面积为1 160km2。这些滑坡是依据地震前后的高分辨率卫星遥感和航片,使用人工目视解译方法圈定出每一个单体滑坡,每个单体滑坡对应一个区要素,并对部分滑坡进行了现场调查验证。基于此,本文选择一个面积为44 031km2的滑坡高密度区域作为研究区,区内滑坡数量为196 007个,面积为1 150.622km2。在原汶川M8.0地震烈度分布图的基础上,基于地震滑坡面积百分比(LAP)分析,建立了地震滑坡面积百分比(滑坡密度)与地震烈度匹配定量标准:LAP≥70%,为XII烈度区;20%≤LAP<70%,为XI烈度区;5%≤LAP<20%,为X烈度区;1%≤LAP<5%,为IX烈度区;LAP<1%,为VIII烈度区及低于VIII烈度的区域。对原烈度图覆盖约123 832km2的VII及VII以上烈度区边界进行了修正。修正前后的烈度图与地震滑坡的匹配度分别为93.8%和95.8%,可见修正后地震滑坡与地震烈度的匹配度提高了2.0个百分点。本文所制定的地震滑坡面积百分比与地震烈度的定量关系,可为其他地震事件,尤其是发生于高山峡谷区地震事件的烈度分布图制作提供方法参考、标准和依据。
May 12, 2008 Wenchuan MW7.9 earthquake triggered a large number of landslides. Based on geographic information system and remote sensing technology, a detailed and complete landslide inventory catalog of Wenchuan earthquake was established. The catalog shows that landslides in the Wenchuan earthquake are mainly distributed in an area of about 110 000 km 2, with an area of 1 160 km 2. These landslides are based on the high-resolution satellite remote sensing and aerial photographs before and after the earthquake. Each single landslide is delineated by artificial visual interpretation method. Each single landslide corresponds to a district element, and some landslides are investigated on site . Based on this, a high-density landslide area of 44,031km2 is selected as the study area, with 196,007 landslides and an area of 1 150.622km2. Based on the original seismic intensity distribution of Wenchuan M8.0 earthquake, the quantitative criteria for the matching of seismic landslide area percentage (seismic intensity) to seismic intensity was established based on LAP analysis: LAP≥70% and XII intensity region. 20% ≤LAP <70% for XI intensity region; 5% ≤LAP <20% for X intensity region; 1% ≤LAP <5% for IX intensity region; LAP <1% for VIII intensity region and low The area of intensity VIII. The boundaries of the areas above the intensity of VII and VII, covering a total area of about 123,832km2, were revised. The matching degree between the seismic intensity before and after the correction and the landslide is 93.8% and 95.8% respectively. It can be seen that the matching degree of the revised seismic landslide and the seismic intensity increased by 2.0%. The quantitative relationship between the percentage of seismic landslides and seismic intensity developed in this paper can provide reference, standard and basis for the method of other seismic events, especially the intensity distribution maps of the seismic events occurring in alpine gorge area.