By analyzing strong ground motion records obtained from the 2008 Wenchuan Ms8.0 earthquake, a ground motion acceleration parameter, named Maximum Critical Acceleration (MCA), is given in this paper. Analyzed result shows that the parameter MCA is more relevant to earthquake-induced landslide than PGA, and by using it we may solve the problems encountered in using PGA criterion to judge whether landslide can be triggered during earthquake.The MCA attenuation relation is built based on the data from the Wenchuan earthquake in Longmenshan mountain area. The appraised landslide area following the attenuation relation well fits the actual landslide distribution in the Wenchuan earthquake-hit area, indicating that this parameter is suitable for evaluating earthquake-induced landslide. Comparing MCA directly with slope critical acceleration may determine whether landslides can be triggered or not,simplifying the judging process of earthquake-induced landslide. The conclusion is that this parameter can be applied to the earthquake-induced landslides evaluation as an earthquake triggering factor.%通过对汶川MS8.0地震强震记录资料的计算分析,给出一个与地震诱发滑坡关系比较密切的地震动加速度参数--最大临界加速度.分析表明,最大临界加速度与地震滑坡的相关性高于峰值加速度,而且可以消除峰值加速度作为判据使用时存在的问题.利用汶川地震强震资料建立了该参数在震区的衰减关系,由衰减关系得到的地震滑坡影响区域与汶川地震滑坡实际分布情况非常接近,表明该参数具有很好的实用价值.利用最大临界加速度直接与斜坡的临界加速度比较,可以给出斜坡是否发生破坏变形的最终结果,简化地震滑坡判别过程.因此认为可将该参数作为地震影响因素引入到地震滑坡灾害判别工作中.
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