The Effect of Earthquake Kinematics on Tsunami Propagation
The Effect of Earthquake Kinematics on Tsunami Propagation
复制标题
地震运动学对海啸传播的影响
DOI：
--
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
D. Rim
中科院分区：
文献类型：
--
作者：
A. Williamson;D. Melgar;D. Rim
海啸是俯冲带地震最具破坏性的影响之一。由于近海仪器有限，大型事件目录稀少，直接观测和了解海啸的产生和传播仍然具有挑战性。这使得将地震破裂的特征与其对海啸产生的影响联系起来变得困难。虽然过去的研究探讨了不同的震源几何形状如何影响海啸成核，但很少有人研究破裂的运动学成分对海啸的作用；我们在这项研究中探索这些影响。虽然过去的研究已经使用沿海验潮仪数据检验了运动学效应，但我们将这种检验扩展到更新的压力计。当使用运动学模型时，我们发现海啸能量的主梁持续旋转，影响远场危险。我们还发现，在沿海和公海测量中，海啸到达时间的延迟可能与整个震源持续时间一样长。对于大地震，在利用公海海啸数据进行震源特征描述时，这种延迟会带来不可忽略的测绘误差。由于我们的发现，我们建议在研究震源持续时间超过120时的S事件和使用公海压力计的记录时，在海啸模拟中包括运动学部分。我们还发现，当单纯关注沿海规范数据和近源灾害时，运动学分量对源不确定性的贡献要小得多，可以忽略不计。
Tsunamis are one of the most destructive effects of subduction zone earthquakes. Directly observing and understanding the generation and propagation of tsunamis remains challenging due to limited offshore instrumentation and a sparse catalog of large events. This makes linking characteristics of the earthquake rupture to their effect on tsunami generation difficult. While past studies explored how varying earthquake source geometries affect tsunami nucleation, little has been done to examine the role of the kinematic component of rupture on the tsunami; we explore these effects in this study. While past studies have examined the kinematic effect using coastal tide gauge data, we expand this examination to more recent pressure gauges. We identify a consistent rotation of the main beam of tsunami energy when using a kinematic model, affecting far‐field hazards. We also identify a delay in tsunami arrival times at both coastal and open‐ocean gauges that can be as long as the total source duration. For large earthquakes, this delay introduces nonnegligible mapping errors when employing open‐ocean tsunami data for source characterizations. As a result of our findings we recommend including a kinematic component to tsunami modeling when studying events with source durations over 120 s and using recordings from open‐ocean pressure gauges. We also find that when focusing purely on coastal gauge data and near‐source hazards, the kinematic component is a much smaller contribution to the source uncertainty and can be ignored.