A Multi-fault Model Estimation from Tsunami Data: An Application to the 2018 M7.9 Kodiak Earthquake
A Multi-fault Model Estimation from Tsunami Data: An Application to the 2018 M7.9 Kodiak Earthquake
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DOI：
10.1007/s00024-020-02433-z
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发表时间：
2020-02-05
影响因子：
2
通讯作者：
Satake, Kenji
中科院分区：
文献类型：
--
作者：
Hossen, M. Jakir;Sheehan, Anne F.;Satake, Kenji
在这项研究中，我们开发了一种新的搜索算法，利用海啸数据找到复杂地震的多断层模型，并将其应用于2018年1月23日的M7.9科迪亚克地震。我们的方法包括一个基于绿色函数的时间反演成像（GFTRI）的方法来反演海面位移使用海啸波形，然后反演海面位移的地震滑移分布。这次地震的全球CMT震源机制表明，断层发生在一个陡峭的断层上，走向N-S（右侧）或E-W（左侧），而随后的工作揭示了更复杂的走滑断层模式。我们使用不同的故障组合进行了一些源反演，以找到基于残差极值的模型。研究结果表明，破裂发生在至少三个断层上，方向大致为南北向和东西向。我们进一步探讨了断层几何参数的扰动范围内建议由以前的工作。我们发现，海面位移模型最适合我们首选的三个断层模型与参数（走向，倾角，倾角）的集合：（165，60，154和（265，60，10）为N-S和E-W方向，分别。
In this study, we developed a new search algorithm to find a multi-fault model of a complex earthquake using tsunami data, and applied it to the January 23, 2018 M7.9 Kodiak earthquake. Our method includes a Green's function based time reverse imaging (GFTRI) approach to invert for sea surface displacement using tsunami waveforms, followed by inversion of the sea surface displacement for the earthquake slip distribution. The global CMT focal mechanism for this event indicates that faulting occurred on a steeply dipping fault striking either N-S (right lateral) or E-W (left lateral), while subsequent work reveals a more complex pattern of strike-slip faulting. We carried out a number of source inversions using different combinations of faults to find the model based on an extremum for residual errors. Our results suggest that the rupture occurred on at least three faults oriented in approximately N-S and E-W directions. We further explored the fault-geometry parameters by perturbing them within a range suggested by previous work. We found that the sea surface displacement model is best fit by our preferred three fault-model with the set of parameters (strike, dip, rake): (165, 60, 154 and (265, 60, 10 for N-S and E-W directions, respectively.