气候变化领域集成服务门户(CCPortal): A high-resolution map of Hawaiian ULVZ morphology from ScS phases

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DOI	10.1016/j.epsl.2021.116885
	A high-resolution map of Hawaiian ULVZ morphology from ScS phases
	Jenkins J.; Mousavi S.; Li Z.; Cottaar S.
发表日期	2021
ISSN	0012821X
卷号	563
英文摘要	We use core reflected ScS waves sensitive to a broad region of the core-mantle boundary beneath Hawaii to create the first high-resolution map of the Hawaiian ultralow-velocity zone (ULVZ). Positive ScS-S differential times are used to identify regions of strong slow velocity anomalies in the lowermost mantle, and the presence of pre/post-cursors around the main ScS phase confirms the sharp top of a basal ULVZ layer. Pre/post-cursor arrivals are mapped into a volume across their region of sensitivity to produce a detailed image of ULVZ morphology. The variability observed across the ULVZ can be interpreted in terms of varying height or velocity reduction, but the large range of velocity variations required to explain observations suggests that most variability reflects varying layer thickness. The Hawaiian ULVZ is observed to be a large-scale regional feature of varying height (∼5-25 km) extending across a wide area along the edge of the Pacific large low-velocity province (LLVP). Variability in previous models of the Hawaiian ULVZ can be explained by studies imaging different parts of this strongly variable, large-scale feature. Maximum ULVZ thicknesses (no taller than 30 km) are found in a flat-topped, steep-sided region on the order of 1000 km in diameter located west of Hawaii. This feature is coincident with the previously identified Hawaiian mega-ULVZ, and is interpreted to represent the root of the Hawaiian plume, which is offset from the volcanic surface expression. A tall, asymmetric ridge of ULVZ material is observed to the east of Hawaii. Both regions of maximum ULVZ heights are bounded by the Pacific LLVP to the south, and fast seismic velocity anomalies interpreted as slab remnants to the north. This points to a potential geodynamical scenario where dense ULVZ material is pushed by subducted slab remnants into thicker piles against LLVP margins. © 2021 Elsevier B.V.
关键词	core-mantle boundary Hawaii plume ultra-low velocity zone
英文关键词	Morphology; Structural geology; % reductions; Core-mantle boundary; Detailed images; Hawaii; High resolution maps; Large-scales; Low-velocity; Lowermost mantle; Plume; Ultralow velocity zone; Velocity; core-mantle boundary; geomorphological mapping; image resolution; lower mantle; plume; seismic velocity; seismic wave; Hawaii [United States]; United States
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/203149
作者单位	Durham University, United Kingdom; Australian National University, Australia; Bullard laboratories, University of Cambridge, United Kingdom
推荐引用方式 GB/T 7714	Jenkins J.,Mousavi S.,Li Z.,et al. A high-resolution map of Hawaiian ULVZ morphology from ScS phases[J],2021,563.
APA	Jenkins J.,Mousavi S.,Li Z.,&Cottaar S..(2021).A high-resolution map of Hawaiian ULVZ morphology from ScS phases.Earth and Planetary Science Letters,563.
MLA	Jenkins J.,et al."A high-resolution map of Hawaiian ULVZ morphology from ScS phases".Earth and Planetary Science Letters 563(2021).