Yamashita Shinji, Yagi Yuji, Okuwaki Ryo, Shimizu Kousuke, Agata Ryoichiro, Fukahata Yukitoshi
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.
Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.
Sci Rep. 2021 Mar 16;11(1):5979. doi: 10.1038/s41598-021-85522-w.
We developed a flexible finite-fault inversion method for teleseismic P waveforms to obtain a detailed rupture process of a complex multiple-fault earthquake. We estimate the distribution of potency-rate density tensors on an assumed model plane to clarify rupture evolution processes, including variations of fault geometry. We applied our method to the 23 January 2018 Gulf of Alaska earthquake by representing slip on a projected horizontal model plane at a depth of 33.6 km to fit the distribution of aftershocks occurring within one week of the mainshock. The obtained source model, which successfully explained the complex teleseismic P waveforms, shows that the 2018 earthquake ruptured a conjugate system of N-S and E-W faults. The spatiotemporal rupture evolution indicates irregular rupture behavior involving a multiple-shock sequence, which is likely associated with discontinuities in the fault geometry that originated from E-W sea-floor fracture zones and N-S plate-bending faults.
我们开发了一种用于远震P波波形的灵活有限断层反演方法，以获取复杂多断层地震的详细破裂过程。我们在假定的模型平面上估计势能率密度张量的分布，以阐明破裂演化过程，包括断层几何形状的变化。我们将该方法应用于2018年1月23日阿拉斯加湾地震，通过在33.6千米深度的投影水平模型平面上表示滑动，以拟合主震发生后一周内发生的余震分布。所获得的震源模型成功解释了复杂的远震P波波形，表明2018年地震破裂了N-S和E-W断层的共轭系统。时空破裂演化表明存在不规则破裂行为，包括多震序列，这可能与源自E-W海底断裂带和N-S板块弯曲断层的断层几何形状不连续有关。
