气候变化领域集成服务门户(CCPortal): Variations in Seismic Wave Speed and VP/VS Ratio in the North American Lithosphere

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DOI	10.1029/2020JB020574
	Variations in Seismic Wave Speed and VP/VS Ratio in the North American Lithosphere
	Golos E.M.; Fang H.; van der Hilst R.D.
发表日期	2020
ISSN	21699313
卷号	125 期号:12
英文摘要	Seismic wave speed is controlled by a number of factors, including temperature and chemical composition, as well as the presence of volatiles and partial melt. Tomography provides a powerful constraint on wave speed variations, but if only VP or VS variations are imaged, it is challenging to separate the competing effects of these factors and make a full interpretation of seismic anomalies. In this study, we generate models of variations in the VP/VS ratio, which introduce new constraints on geologic structures, compositions, and processes. We invert P and S wave arrival times, as well as Rayleigh wave phase velocities, utilizing the sensitivity of Rayleigh waves to both VP and VS to form mutually constrained but independent models of VP and VS structure at lithospheric depths below the continental United States and Southeastern Canada. From this we can examine variations in VP/VS, highlighting a distinct pattern of anomalies which are less readily observed in VP or VS alone. A clustering analysis is performed to relate 1-D profiles of wave speed as a function of depth to tectonic provinces. While the first-order structure of VP and VS appears to be dominated by the thermal contrast between the Eastern and Western United States, the strongest control over VP/VS ratio perturbations within the mantle lithosphere appears to be the presence of melt. Certain higher-VP/VS anomalies within the cratonic interior may reflect compositional anomalies and variations in Moho structure. This work provides a continental-scale framework for future quantitative analyses of thermal and compositional heterogeneity, and for targeted geologic interpretation. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	continental lithosphere; joint inversion; North America; partial melt; seismic tomography; VP/VS ratio
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/187438
作者单位	Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States; Now at Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, United States
推荐引用方式 GB/T 7714	Golos E.M.,Fang H.,van der Hilst R.D.. Variations in Seismic Wave Speed and VP/VS Ratio in the North American Lithosphere[J],2020,125(12).
APA	Golos E.M.,Fang H.,&van der Hilst R.D..(2020).Variations in Seismic Wave Speed and VP/VS Ratio in the North American Lithosphere.Journal of Geophysical Research: Solid Earth,125(12).
MLA	Golos E.M.,et al."Variations in Seismic Wave Speed and VP/VS Ratio in the North American Lithosphere".Journal of Geophysical Research: Solid Earth 125.12(2020).