气候变化领域集成服务门户(CCPortal): Lower-Crustal Seismicity on the Eastern Border Faults of the Main Ethiopian Rift

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DOI	10.1029/2020JB020030
	Lower-Crustal Seismicity on the Eastern Border Faults of the Main Ethiopian Rift
	Lapins S.; Kendall J.M.; Ayele A.; Wilks M.; Nowacki A.; Cashman K.V.
发表日期	2020
ISSN	21699313
卷号	125 期号:8
英文摘要	Lower-crustal seismicity is commonly observed in continental rift zones despite the crust at such depths being ductile enough to prohibit brittle failure. The source of such deep seismicity across the East African Rift remains an outstanding question. Here we present analysis of an isolated cluster of lower-crustal earthquakes located on the eastern border faults of the Main Ethiopian Rift, near the Corbetti caldera. Lower-crustal earthquakes have not previously been observed in this area. Phase arrival times were determined using an automated picking approach based on continuous wavelet transform and statistical changepoint detection methods. We overcome misinterpretations from large hypocenter depth errors by considering mixture distributions for all events and their associated uncertainties. These mixture distributions represent probability density functions of any event occurring at a given depth. The mixture distribution mode for a variety of different velocity models and error parameters remained stable at a depth of 28–32 km, with the vast majority of maximum likelihood estimates for individual hypocenters located at depths of 25–35 km. Most events occur over a 2 month period, with 90% of cumulative seismic moment occurring during March and April 2012. The ephemeral and localized nature of this seismicity, combined with low event magnitudes and regional hydrothermal/magmatic activity, suggests that these lower-crustal events are likely related to fluid or magmatic processes. Plausible mechanisms include the movement of magma and/or exsolution of volatiles at depth causing transient high strain rates and pore fluid pressures that induce seismicity. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	continental rift; continuous wavelet transform; deep magmatic processes; low oscillation Morlet wavelet; mixture distributions; wild binary segmentation
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/187727
作者单位	School of Earth Sciences, University of Bristol, Bristol, United Kingdom; Department of Earth Sciences, University of Oxford, Oxford, United Kingdom; Institute of Geophysics, Space Science and Astronomy, Addis Ababa University, Addis Ababa, Ethiopia; School of Earth and Environment, University of Leeds, Leeds, United Kingdom
推荐引用方式 GB/T 7714	Lapins S.,Kendall J.M.,Ayele A.,et al. Lower-Crustal Seismicity on the Eastern Border Faults of the Main Ethiopian Rift[J],2020,125(8).
APA	Lapins S.,Kendall J.M.,Ayele A.,Wilks M.,Nowacki A.,&Cashman K.V..(2020).Lower-Crustal Seismicity on the Eastern Border Faults of the Main Ethiopian Rift.Journal of Geophysical Research: Solid Earth,125(8).
MLA	Lapins S.,et al."Lower-Crustal Seismicity on the Eastern Border Faults of the Main Ethiopian Rift".Journal of Geophysical Research: Solid Earth 125.8(2020).