气候变化领域集成服务门户(CCPortal): Origin of temporal changes of inner-core seismic waves

CCPortal

DOI	10.1016/j.epsl.2020.116267
	Origin of temporal changes of inner-core seismic waves
	Yang Y.; Song X.
发表日期	2020
ISSN	0012821X
卷号	541
英文摘要	Temporal changes of inner-core (IC) seismic phases have been confirmed with high-quality waveform doublets. However, the nature of the temporal changes is still controversial. We investigated systematically the temporal changes of IC refracted (PKIKP) and reflected (PKiKP) waves with a large data set of waveform doublets. We used non-IC reference phase (mainly SKP), which eliminated ambiguity where the temporal changes come from. We found that the temporal changes have always started at refracted PKIKP and the travel time changes correlate better with PKIKP. Changes in reflected PKiKP can be easily contaminated by the strong and time-varying PKIKP and coda wave trains and therefore are not reliable indicators for IC boundary changes. Combining with previous observations, we conclude that the temporal changes come mostly (if not all) from the IC interior and IC surface changes as the sole source suggested previously can be ruled out. The differential rotation of the IC shifting its heterogeneous uppermost structures is the simplest and most reasonable explanation for the origin of the time-varying IC waves. A rotation rate of about 0.05-0.1° per year with possible decadal fluctuation can reconcile all temporal change observations from body waves, IC scattering, and normal mode data. © 2020 Elsevier B.V.
关键词	inner core rotation PKIKP PKiKP temporal change waveform doublet
英文关键词	Seismology; Differential rotation; High quality; Large datasets; Rotation rate; Seismic phasis; Surface changes; Temporal change; Time varying; Integrated circuits; inner core; seismic velocity; seismic wave; seismology; temporal analysis; temporal variation; travel time
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/202987
作者单位	Department of Geology, University of Illinois at Urbana-Champaign, Urbana, United States; Institute of Theoretical and Applied Geophysics, School of Earth and Space Sciences, Peking University, Beijing, China
推荐引用方式 GB/T 7714	Yang Y.,Song X.. Origin of temporal changes of inner-core seismic waves[J],2020,541.
APA	Yang Y.,&Song X..(2020).Origin of temporal changes of inner-core seismic waves.Earth and Planetary Science Letters,541.
MLA	Yang Y.,et al."Origin of temporal changes of inner-core seismic waves".Earth and Planetary Science Letters 541(2020).