Wei Xueting, Xu Jiankuan, Liu Yuxiang, Chen Xiaofei
School of Earth and Space Sciences, University of Science and Technology of China, 230026, Hefei, China.
Department of Earth and Space Sciences, Southern University of Science and Technology, 518055, Shenzhen, China.
Nat Commun. 2021 Sep 15;12(1):5464. doi: 10.1038/s41467-021-25823-w.
Low-frequency earthquakes are a series of recurring small earthquakes that are thought to compose tectonic tremors. Compared with regular earthquakes of the same magnitude, low-frequency earthquakes have longer source durations and smaller stress drops and slip rates. The mechanism that drives their unusual type of stress accumulation and release processes is unknown. Here, we use phase diagrams of rupture dynamics to explore the connection between low-frequency earthquakes and regular earthquakes. By comparing the source parameters of low-frequency earthquakes from 2001 to 2016 in Parkfield, on the San Andreas Fault, with those from numerical simulations, we conclude that low-frequency earthquakes are earthquakes that self-arrest within the rupture patch without any introduced interference. We also explain the scaling property of low-frequency earthquakes. Our findings suggest a framework for fault deformation in which nucleation asperities can release stress through slow self-arrest processes.
低频地震是一系列反复出现的小地震，被认为构成了构造微震。与相同震级的常规地震相比，低频地震的震源持续时间更长，应力降和滑动速率更小。驱动其异常应力积累和释放过程的机制尚不清楚。在这里，我们使用破裂动力学相图来探索低频地震与常规地震之间的联系。通过比较2001年至2016年圣安德烈亚斯断层帕克菲尔德的低频地震源参数与数值模拟的参数，我们得出结论，低频地震是在破裂区内自行停止且无任何外界干扰的地震。我们还解释了低频地震的标度性质。我们的研究结果提出了一个断层变形框架，其中成核粗糙体可以通过缓慢的自行停止过程释放应力。
