This paper proposes a mechanism of earthquake-induced landslides with pulse-like ground motion (PLGM) based on the discontinuous deformation analysis (DDA) method. In recent near-fault earthquake-induced landslides, the two phenomena confusing landslide researchers are observed. One is that large-scale landslides occurred in the area with small PGA but no landslide in the area with large PGA, for example, the landslides occurred during the 2016 Kumamoto earthquake. The other is that one side slopes collapsed while the opposite side slopes back to back remain stable. For example, most west-faced slopes collapsed while the east-faced slopes back to back remain stable in the 2018 Hokkaido earthquake. To explain the two phenomena in near-fault earthquake-induced landslides with PLGM, a symmetrical slope model subjected to different ground motions during these two earthquakes are analyzed and discussed by using the DDA method. The analysis results show that PLGM may be a major triggering factor for co-seismic landslides in the near-fault region, while PGA may not be the right parameter for the initiation of the earthquake-induced landslides. Meanwhile, the aspect of collapsed slope is related to both the velocity pulse of PLGM and strength parameters of the slope. The proposed mechanism for the earthquake-induced landslides in the near-fault region with PLGM considers both tensile and shear strengths of the slope, which can well explain the landslide initiation phenomena in the 2016 Kumamoto earthquake and the 2018 Hokkaido earthquake. The relationship between PLGM and forward directivity effect is also studied in combination with two earthquake cases to more accurately clarify the mechanism of the initiation of co-seismic landslides in the near-fault region.

中文翻译：

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关注脉冲式地面运动的地震诱发滑坡的可能机制

本文基于不连续变形分析（DDA）方法提出了一种具有脉冲状地面运动（PLGM）的地震诱发滑坡机制。在最近的近断层地震诱发的滑坡中，观察到了让滑坡研究人员感到困惑的两种现象。一是PGA较小的地区发生了大规模滑坡，而PGA较大的地区没有发生滑坡，例如2016年熊本地震期间发生的滑坡。另一种是一侧斜坡倒塌，而另一侧背靠背的斜坡保持稳定。例如，在 2018 年北海道地震中，大部分西面斜坡倒塌，而背靠背的东面斜坡保持稳定。为了用 PLGM 解释近断层地震诱发的滑坡中的两种现象，使用DDA方法分析和讨论了在这两次地震中受到不同地震动作用的对称边坡模型。分析结果表明，PLGM可能是近断层区同震滑坡的主要触发因素，而PGA可能不是引发地震诱发滑坡的正确参数。同时，边坡坍塌的情况与PLGM的速度脉冲和边坡的强度参数有关。PLGM近断层区地震诱发滑坡的机制考虑了边坡的抗拉强度和抗剪强度，可以很好地解释2016年熊本地震和2018年北海道地震中的滑坡萌生现象。