气候变化领域集成服务门户(CCPortal): Seismic evidence of fluid migration in northeastern Japan after the 2011 Tohoku-Oki earthquake

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DOI	10.1016/j.epsl.2021.116894
	Seismic evidence of fluid migration in northeastern Japan after the 2011 Tohoku-Oki earthquake
	Wang Q.-Y.; Campillo M.; Brenguier F.; Lecointre A.; Takeda T.; Yoshida K.
发表日期	2021
ISSN	0012821X
卷号	563
英文摘要	We use ambient-noise-based seismic monitoring to detect an anomalous seismic velocity decrease (∼0.01%) widely distributed in Honshu that arose about 1 year after the 2011 Mw 9.0 Tohoku-Oki earthquake. The anomaly is located along the central quaternary volcanic axis, and it suggests that the changes are related to volcanic processes. After correction for possible external environmental forcing-related velocity changes, the anomaly in the seismic velocity remains, which implies that it is associated with some internal physical process. We show a general strong positive correlation between the seismic velocity changes and the intensity of ground motion derived from the daily cumulative seismic moment. However, the lack of correlation during the anomaly itself reveals that this reduction is not directly caused by earthquake shaking. Tiltmeter low-pass observations show temporal variations that are correlated with the velocity changes. These observations strengthen the hypothesis of actual physical deformation. A previously reported decrease in fault strength (∼10%) for the same period as the velocity anomaly further supports a physical property change in the upper crust. We also note a simultaneous increase in activity of low-frequency events in the volcanic area, which suggests an increase in pore pressure in the upper crust. We propose that the observed anomalous seismic velocity decrease in early 2012 is due to an increase in pore pressure induced by an upward fluid migration, which at the same time triggered the increase in fluid-driven swarm seismicity and low-frequency events. We recall the depth-dependent seismic velocity changes in Honshu and derive an average diffusion of 1 m2/s over around 11 months after the Tohoku-Oki earthquake. © 2021 Elsevier B.V.
关键词	fault strength fluid migration low frequency earthquakes pore pressure seismic velocity drop anomaly tiltmeter observation
英文关键词	Diffusion in liquids; Earthquakes; Pore pressure; Fault strength; Fluid migration; Low-frequency earthquakes; Lower frequencies; Seismic velocities; Seismic velocity drop anomaly; Tiltmeter observation; Tohoku-Oki earthquakes; Upper crust; Velocity changes; Volcanoes; correlation; deformation; earthquake swarm; fault geometry; fluid flow; ground motion; pore pressure; seismic noise; seismic velocity; strength; Tohoku earthquake 2011; trigger mechanism; Honshu; Japan
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203327
作者单位	Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, United States; Université Grenoble Alpes, CNRS, ISTerre, Grenoble, France; National Research Institute for Earth Science and Disaster Resilience, Japan; Department of Geophysics, Graduate School of Science, Tohoku University, Japan
推荐引用方式 GB/T 7714	Wang Q.-Y.,Campillo M.,Brenguier F.,et al. Seismic evidence of fluid migration in northeastern Japan after the 2011 Tohoku-Oki earthquake[J],2021,563.
APA	Wang Q.-Y.,Campillo M.,Brenguier F.,Lecointre A.,Takeda T.,&Yoshida K..(2021).Seismic evidence of fluid migration in northeastern Japan after the 2011 Tohoku-Oki earthquake.Earth and Planetary Science Letters,563.
MLA	Wang Q.-Y.,et al."Seismic evidence of fluid migration in northeastern Japan after the 2011 Tohoku-Oki earthquake".Earth and Planetary Science Letters 563(2021).