气候变化领域集成服务门户(CCPortal): Constraints on the Upper Mantle Structure Beneath the Pacific From 3-D Anisotropic Waveform Modeling

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DOI	10.1029/2020JB020003
	Constraints on the Upper Mantle Structure Beneath the Pacific From 3-D Anisotropic Waveform Modeling
	Kendall E.; Ferreira A.M.G.; Chang S.-J.; Witek M.; Peter D.
发表日期	2021
ISSN	21699313
卷号	126 期号:4
英文摘要	Seismic radial anisotropy is a crucial tool to help constrain flow in the Earth's mantle. However, Earth structure beneath the oceans imaged by current 3-D radially anisotropic mantle models shows large discrepancies. Here, we provide constraints on the radially anisotropic upper mantle structure beneath the Pacific by waveform modeling and subsequent inversion. Specifically, we objectively evaluate three 3-D tomography mantle models which exhibit varying distributions of radial anisotropy through comparisons of independent real data sets with synthetic seismograms computed with the spectral-element method. The data require an asymmetry at the East Pacific Rise (EPR) with stronger positive radial anisotropy ξ = (Formula presented.) = 1.13–1.16 at ∼100 km depth to the west of the EPR than to the east (ξ = 1.11–1.13). This suggests that the anisotropy in this region is due to the lattice-preferred orientation of anisotropic mantle minerals produced by shear-driven asthenospheric flow beneath the South Pacific Superswell. Our new radial anisotropy constraints in the Pacific show three distinct positive linear anomalies at ∼100 km depth. These anomalies are possibly related to mantle entrainment at the Nazca-South America subduction zone, flow at the EPR and from the South Pacific Superswell and shape-preferred orientation (SPO) of melt beneath Hawaii. Radial anisotropy reduces with lithospheric age to ξ < 1.05 in the west at ∼100 km depth, which possibly reflects a deviation from horizontal flow as the mantle is entrained with subducting slabs, a change in temperature or water content that could alter the anisotropic olivine fabric or the SPO of melt. © 2021. The Authors.
英文关键词	mantle flow; Pacific; seismic anisotropy; upper mantle; waveform modeling
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/187250
作者单位	Department of Earth Sciences, University College London, London, United Kingdom; CERIS, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal; Division of Geology and Geophysics, Kangwon National University, Chuncheon, South Korea; Extreme Computing Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
推荐引用方式 GB/T 7714	Kendall E.,Ferreira A.M.G.,Chang S.-J.,et al. Constraints on the Upper Mantle Structure Beneath the Pacific From 3-D Anisotropic Waveform Modeling[J],2021,126(4).
APA	Kendall E.,Ferreira A.M.G.,Chang S.-J.,Witek M.,&Peter D..(2021).Constraints on the Upper Mantle Structure Beneath the Pacific From 3-D Anisotropic Waveform Modeling.Journal of Geophysical Research: Solid Earth,126(4).
MLA	Kendall E.,et al."Constraints on the Upper Mantle Structure Beneath the Pacific From 3-D Anisotropic Waveform Modeling".Journal of Geophysical Research: Solid Earth 126.4(2021).