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Seismological evidence for a localized mushy zone at the Earth’s inner core boundary

Although existence of a mushy zone in the Earth’s inner core has been hypothesized several decades ago, no seismic evidence has ever been reported. Based on waveform modeling of seismic compressional waves that are reflected off the Earth’s inner core boundary, here we present seismic evidence for a...

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Detalles Bibliográficos
Autores principales: Tian, Dongdong, Wen, Lianxing
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5537277/
https://www.ncbi.nlm.nih.gov/pubmed/28761098
http://dx.doi.org/10.1038/s41467-017-00229-9
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author Tian, Dongdong
Wen, Lianxing
author_facet Tian, Dongdong
Wen, Lianxing
author_sort Tian, Dongdong
collection PubMed
description Although existence of a mushy zone in the Earth’s inner core has been hypothesized several decades ago, no seismic evidence has ever been reported. Based on waveform modeling of seismic compressional waves that are reflected off the Earth’s inner core boundary, here we present seismic evidence for a localized 4–8 km thick zone across the inner core boundary beneath southwest Okhotsk Sea with seismic properties intermediate between those of the inner and outer core and of a mushy zone. Such a localized mushy zone is found to be surrounded by a sharp inner core boundary nearby. These seismic results suggest that, in the current thermo-compositional state of the Earth’s core, the outer core composition is close to eutectic in most regions resulting in a sharp inner core boundary, but deviation from the eutectic composition exists in some localized regions resulting in a mushy zone with a thickness of 4–8 km.
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spelling pubmed-55372772017-08-07 Seismological evidence for a localized mushy zone at the Earth’s inner core boundary Tian, Dongdong Wen, Lianxing Nat Commun Article Although existence of a mushy zone in the Earth’s inner core has been hypothesized several decades ago, no seismic evidence has ever been reported. Based on waveform modeling of seismic compressional waves that are reflected off the Earth’s inner core boundary, here we present seismic evidence for a localized 4–8 km thick zone across the inner core boundary beneath southwest Okhotsk Sea with seismic properties intermediate between those of the inner and outer core and of a mushy zone. Such a localized mushy zone is found to be surrounded by a sharp inner core boundary nearby. These seismic results suggest that, in the current thermo-compositional state of the Earth’s core, the outer core composition is close to eutectic in most regions resulting in a sharp inner core boundary, but deviation from the eutectic composition exists in some localized regions resulting in a mushy zone with a thickness of 4–8 km. Nature Publishing Group UK 2017-08-01 /pmc/articles/PMC5537277/ /pubmed/28761098 http://dx.doi.org/10.1038/s41467-017-00229-9 Text en © The Author(s) 2017 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Tian, Dongdong
Wen, Lianxing
Seismological evidence for a localized mushy zone at the Earth’s inner core boundary
title Seismological evidence for a localized mushy zone at the Earth’s inner core boundary
title_full Seismological evidence for a localized mushy zone at the Earth’s inner core boundary
title_fullStr Seismological evidence for a localized mushy zone at the Earth’s inner core boundary
title_full_unstemmed Seismological evidence for a localized mushy zone at the Earth’s inner core boundary
title_short Seismological evidence for a localized mushy zone at the Earth’s inner core boundary
title_sort seismological evidence for a localized mushy zone at the earth’s inner core boundary
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5537277/
https://www.ncbi.nlm.nih.gov/pubmed/28761098
http://dx.doi.org/10.1038/s41467-017-00229-9
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