气候变化领域集成服务门户(CCPortal): Variations in the Seismogenic Thickness of East Africa

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DOI	10.1029/2020JB020754
	Variations in the Seismogenic Thickness of East Africa
	Craig T.J.; Jackson J.A.
发表日期	2021
ISSN	21699313
卷号	126 期号:3
英文摘要	The well-established variation in the depth of earthquakes along both branches of the East African Rift System offers an opportunity to probe the controls on the depth-extent of seismogenesis, and the length-scales over which this may vary. We present an updated compilation of well-determined earthquake depths from teleseismic and regional seismic data for the East African Rift System, combined with a summary of the depth distribution of smaller-magnitude microseismicity from 13 local network deployments. Moderate-to-large magnitude (Mw > 5) earthquakes, unrelated to the movement of magmatic fluids, beneath Afar, the Main Ethiopian Rift, and the northernmost sections of the Eastern Branch, are confined to the upper crust. Seismicity along the Western Branch, and the southern-most sections of the Eastern Branch extends deeper, into the lower crust, in places to depths close to the local Moho. Along the Eastern Branch, in northern Tanzania, the transition between these two regimes occurs over a distance of ≤40 km, requiring a change to a higher temperature cutoff for the deeper earthquakes; an effect that must be compositional in origin. This compositional variation in the lower crust is most likely related to the degree of hydration. Earthquakes deep within the lower crust are therefore likely to be a proxy for an anhydrous crustal composition. © 2021. The Authors.
英文关键词	crust; earthquakes; East Africa; lithosphere; rheology; seismicity
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/187290
作者单位	School of Earth and Environment, COMET, Institute of Geophysics and Tectonics, University of Leeds, Leeds, United Kingdom; Department of Earth Sciences, COMET, University of Cambridge, Cambridge, United Kingdom
推荐引用方式 GB/T 7714	Craig T.J.,Jackson J.A.. Variations in the Seismogenic Thickness of East Africa[J],2021,126(3).
APA	Craig T.J.,&Jackson J.A..(2021).Variations in the Seismogenic Thickness of East Africa.Journal of Geophysical Research: Solid Earth,126(3).
MLA	Craig T.J.,et al."Variations in the Seismogenic Thickness of East Africa".Journal of Geophysical Research: Solid Earth 126.3(2021).