气候变化领域集成服务门户(CCPortal): Eastward mantle flow field underneath East Asia quantified by combining shear-wave splitting orientations and absolute plate motion observations

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DOI	10.1016/j.epsl.2021.116969
	Eastward mantle flow field underneath East Asia quantified by combining shear-wave splitting orientations and absolute plate motion observations
	Li Z.; Kreemer C.
发表日期	2021
ISSN	0012821X
卷号	566
英文摘要	Although Earth's surface motion is well known, the flow field in the underlying mantle is not. Mantle flow is typically calculated on the basis of inferred density variations, and flow directions can also be reflected in seismically observed anisotropy, but those observations leave ambiguity on the depth and direction of the deformation. Anisotropy orientations in East Asia, outside Tibet, have been interpreted in various ways and have often been linked to deformation in the asthenosphere related to absolute plate motion and/or mantle wedge deformation. Here, we re-analyze published seismic anisotropy data and find that orientations outside Tibet can be much better explained when considering absolute plate motion (APM) of the Earth's surface in addition to coherent sub-asthenospheric mantle flow, than when comparing orientations to APM alone. The direction and magnitude of the required sub-asthenospheric flow depend on the absolute reference frame used for the surface velocities, but when considering an APM frame with an intermediate global net-rotation we find an eastward flow of 1-2 cm/yr. This flow is faster than the surface motion, and generally in the same direction, from which we conclude that the mantle leads the plate motion. Our inferred flow is similar to those independently calculated based on buoyancy forces driven by density variations, most notably the high density anomalies associated with the western Pacific subduction zones, but possibly also the upwelling underneath Africa. Additionally, based on our predicted sub-asthenospheric flow and absolute motion of the lithosphere, we predict asthenospheric-based XKS orientations underneath all of east Asia and find it to differ significantly with observed XKS orientations where either the lithosphere is thick and/or strain rate is high, which suggests that at those places observed XKS orientations reflect the integrated deformation in both asthenosphere and lithosphere. © 2021 Elsevier B.V.
关键词	absolute plate motion density-driven flow East Asia seismic anisotropy shear-wave splitting orientations sub-asthenospheric mantle flow
英文关键词	Anisotropy; Deformation; Flow fields; Shear flow; Shear waves; Strain rate; Structural geology; Absolute plate motions; Density driven flows; Density variations; Earth's surface; East Asia; Mantle flow; Seismic anisotropy; Shear-wave splitting orientation; Sub-asthenospheric mantle flow; Surface motions; Seismology; asthenosphere; density current; flow field; mantle process; plate motion; S-wave; seismic anisotropy; wave splitting; Far East
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/203187
作者单位	The Second Monitoring and Application Center, China Earthquake Administration, Xi'an, 710054, China; State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing, 100029, China; Nevada Bureau of Mines and Geology, Seismological Laboratory, University of Nevada, Reno, NV 89557, United States
推荐引用方式 GB/T 7714	Li Z.,Kreemer C.. Eastward mantle flow field underneath East Asia quantified by combining shear-wave splitting orientations and absolute plate motion observations[J],2021,566.
APA	Li Z.,&Kreemer C..(2021).Eastward mantle flow field underneath East Asia quantified by combining shear-wave splitting orientations and absolute plate motion observations.Earth and Planetary Science Letters,566.
MLA	Li Z.,et al."Eastward mantle flow field underneath East Asia quantified by combining shear-wave splitting orientations and absolute plate motion observations".Earth and Planetary Science Letters 566(2021).