气候变化领域集成服务门户(CCPortal): Evidence of Overtone Interference in Fundamental-Mode Rayleigh Wave Phase and Amplitude Measurements

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DOI	10.1029/2019JB018540
	Evidence of Overtone Interference in Fundamental-Mode Rayleigh Wave Phase and Amplitude Measurements
	Hariharan A.; Dalton C.A.; Ma Z.; Ekström G.
发表日期	2020
ISSN	21699313
卷号	125 期号:1
英文摘要	We present evidence that measurements of minor-arc fundamental-mode (FM) Rayleigh waves experience interference from major-arc overtones, resulting in travel-time and amplitude measurements oscillating along a ray path. The oscillations are present in synthetic seismograms generated in a 3-D Earth model via SPECFEM3D_GLOBE and in a 1-D Earth model by mode summation. The absence of oscillations in synthetics containing only the FM indicates that the oscillations originate from higher-mode interference. This interference is present across multiple measurement techniques, including multi-channel cross correlation, phase-matched filtering, and cluster analysis. Experiments with 1-D synthetics suggest that contamination from interference is largest at epicentral distances greater than around 120 degrees, where record sections of seismograms show the major-arc overtones intersecting the minor-arc FM Rayleigh wave. The short wavelength of the interference pattern means it is only observable with dense station spacing and high data quality, which may explain why it has not, to our knowledge, been previously recognized. We show the interference is visible in real data. Its overall impact on phase-velocity maps is probably minor due to many measurements from shorter path lengths less prone to interference bias. However, phase-velocity maps constructed only from measurements at epicentral distances prone to interference exhibit significant noise and poor agreement with maps from measurements that include all path lengths; the issue is especially problematic for approaches that use differential travel times between nearby stations. Accounting for interference may diminish noise in measurements and improve the accuracy of images of the upper mantle. ©2019. American Geophysical Union. All Rights Reserved.
英文关键词	Free Oscillations; Overtone Interference; Rayleigh Waves
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/188032
作者单位	Brown University, Department of Earth, Environmental, and Planetary Sciences, United States; Tongji University, School of Ocean and Earth Science, China; Lamont-Doherty Earth Observatory of Columbia University, United States
推荐引用方式 GB/T 7714	Hariharan A.,Dalton C.A.,Ma Z.,et al. Evidence of Overtone Interference in Fundamental-Mode Rayleigh Wave Phase and Amplitude Measurements[J],2020,125(1).
APA	Hariharan A.,Dalton C.A.,Ma Z.,&Ekström G..(2020).Evidence of Overtone Interference in Fundamental-Mode Rayleigh Wave Phase and Amplitude Measurements.Journal of Geophysical Research: Solid Earth,125(1).
MLA	Hariharan A.,et al."Evidence of Overtone Interference in Fundamental-Mode Rayleigh Wave Phase and Amplitude Measurements".Journal of Geophysical Research: Solid Earth 125.1(2020).