气候变化领域集成服务门户(CCPortal): Temporal Changes of the Inner Core From Globally Distributed Repeating Earthquakes

CCPortal

DOI	10.1029/2019JB018652
	Temporal Changes of the Inner Core From Globally Distributed Repeating Earthquakes
	Yang Y.; Song X.
发表日期	2020
ISSN	21699313
卷号	125 期号:3
英文摘要	Time-dependent travel times of seismic waves traversing the inner core from repeating earthquakes provided compelling evidence for an inner core differential motion. Here we conducted a systematic search for strong repeating earthquakes in the last three decades to examine the global pattern of temporal changes of the inner core. We performed extensive analyses on the quality of the repeating earthquakes and quantified the error (σic) of travel time measurements from all possible sources except the inner core temporal changes. We set 2σic as a threshold for judging whether an inner core temporal change is significant. No significant temporal changes were found in most parts of the inner core, but large temporal changes (over 3σic) were observed beneath four regions in Northern Hemisphere (North Atlantic, Northeast Pacific, Russian Far East/Sea of Okhotsk, and Europe/North Africa), besides the well-known Central America anomaly in previous studies. Most large temporal changes were associated with time lapses of over 6 years and smaller distances, possibly resulting from the rotation shifting the laterally varying top 300 km of the inner core. A new path sampling North Atlantic suggested a small-scale and steep lateral velocity gradient of the inner core and a slow eastward inner core rotation of 0.051°/year. Small-scale lateral variations may reconcile large difference in the estimates of the inner core rotation rate. We also observed enigmatic very large abrupt temporal changes (as short as 44 days), which may be related to disturbances caused by the great Sumatra earthquakes. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	cross correlation; inner core; inner core rotation; PKP; repeating earthquakes; temporal changes
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187923
作者单位	Department of Geology, University of Illinois at Urbana-Champaign, Urbana, IL, United States; Institute of Theoretical and Applied Geophysics, Peking University, Beijing, China
推荐引用方式 GB/T 7714	Yang Y.,Song X.. Temporal Changes of the Inner Core From Globally Distributed Repeating Earthquakes[J],2020,125(3).
APA	Yang Y.,&Song X..(2020).Temporal Changes of the Inner Core From Globally Distributed Repeating Earthquakes.Journal of Geophysical Research: Solid Earth,125(3).
MLA	Yang Y.,et al."Temporal Changes of the Inner Core From Globally Distributed Repeating Earthquakes".Journal of Geophysical Research: Solid Earth 125.3(2020).