Structural Heterogeneity Controlled Rupture Process of the 2021 Mw 7.1 Fukushima, Japan, Earthquake Revealed by Joint Inversion of Seismic and Geodetic Data

中文摘要（来自计算机智能翻译）

在这项研究中，我们确定了 2021 年日本东北部附近的 M-w7.1 福岛地震的破裂模型，并采用该模型研究了这次地震及其余震的原因。破裂模型是通过远震、强震和大地测量数据的联合反演获得的。结果表明，滑动主要分布在地震震中的西南侧，表明是单侧破裂事件。我们观察到地震矩在三个时间段内释放，在断层面上产生了四个滑动斑块。通过比较，我们证明了我们的联合反演模型在描述福岛地震的破裂过程方面比仅使用强震数据确定的自动反演模型更可靠。通过联合分析滑动分布和地震速度结构，我们发现滑动斑块与 V-P/V-S 异常之间存在良好的相关性，这表明断层带沿线的结构非均质性在控制福岛地震的破裂过程中起着关键作用。此外，大多数余震位于以小滑动和高 V-P/V-S 为特征的区域，我们证明它们是由主震引起的流体存在和破裂导致的应力变化引起的。

英文摘要

We determined the rupture model of the 2021 M-w 7.1 Fukushima earthquake near northeastern Japan in this study and adopted this model to investigate the cause of this earthquake and its aftershocks. The rupture model was obtained through joint inversion of teleseismic, strong -motion and geodetic data. It is shown that the slips were predominantly distributed on the southwest side of the earthquake epicenter, indicating a unilateral rupture event. We observed that the seismic moment was released in three time periods, producing four slip patches on the fault plane. Through comparison, we demonstrated that our joint inversion model was more reliable in describing the rupture process of the Fukushima earthquake than the automatic inversion models determined using only strong -motion data. By jointly analyzing the slip distribution and seismic velocity structure, we found a good correlation between the slip patches and V-P / V-S anomalies, suggesting that structural heterogeneities along the fault zone played a critical role in controlling the rupture process of the Fukushima earthquake. In addition, most aftershocks were located in the region characterized by small slips and high V-P / V-S , and we demonstrated that they were caused by stress changes due to the presence of fluids and the rupture of the mainshock.