The Origin of Large, Long‐Period Near‐Fault Ground Velocities During Surface‐Breaking Strike‐Slip Earthquakes
The Origin of Large, Long‐Period Near‐Fault Ground Velocities During Surface‐Breaking Strike‐Slip Earthquakes
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DOI：
10.1029/2022gl098029
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发表时间：
2022-05
影响因子：
5.2
通讯作者：
Y. Kaneko;H. Goto
中科院分区：
文献类型：
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作者：
Y. Kaneko;H. Goto
最近地表破裂地震的近断层地面运动记录的特点是大（>几米/秒），长周期（几秒）的地面速度脉冲，这可能会对高层建筑和大型基础设施造成重大危害。然而，生成机制还没有得到很好的理解。在这里，使用自发破裂模拟，我们研究了在2016年熊本（日本）地震期间观察到的大速度脉冲的起源。我们表明，近断层波形数据以及地震学估计的力矩和辐射能量可以很好地再现一个相对简单的模型与均匀的沿着走向预应力和摩擦性能。我们的研究结果表明，大的、长周期的地面速度是由传播破裂和地球表面的动态相互作用引起的，这种相互作用被来自低速层边界的反射波所增强。这样一个通用的机制表明，大，长周期的地面运动是一个常见的发生在近断层地区的表面破裂，走滑地震。
Records of near‐fault ground motions from recent surface‐breaking earthquakes are characterized by large (> a few m/s), long‐period (a few seconds) ground velocity pulses, which may pose significant hazard for tall buildings and large infrastructures. Yet, the generation mechanism is not well understood. Here, using spontaneous rupture simulations, we examine the origin of large velocity pulses observed during the 2016 Mw7.0 Kumamoto (Japan) earthquake. We show that near‐fault waveform data as well as seismologically estimated moment and radiated energy can be well reproduced by a relatively simple model with uniform along‐strike pre‐stress and frictional properties. Our results suggest that large, long‐period ground velocities are caused by the dynamic interaction of propagating rupture and the Earth's surface, which is enhanced by reflected waves from the boundaries of low‐velocity layers. Such a generic mechanism suggests that large, long‐period ground motion is a common occurrence in near‐fault regions during surface‐breaking, strike‐slip earthquakes.