Short wavelength topography on the inner-core boundary
Constraining the topography of the inner-core boundary is important for studies of core–mantle coupling and the generation of the geodynamo. We present evidence for significant temporal variability in the amplitude of the inner core reflected phase PKiKP for an exceptionally high-quality earthquake...
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ftpubmed:oai:pubmedcentral.nih.gov:1765456 2023-05-15T18:23:34+02:00 Short wavelength topography on the inner-core boundary Cao, Aimin Masson, Yder Romanowicz, Barbara 2007-01-02 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1765456 http://www.ncbi.nlm.nih.gov/pubmed/17190798 https://doi.org/10.1073/pnas.0609810104 en eng National Academy of Sciences http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1765456 http://www.ncbi.nlm.nih.gov/pubmed/17190798 http://dx.doi.org/10.1073/pnas.0609810104 © 2006 by The National Academy of Sciences of the USA Physical Sciences Text 2007 ftpubmed https://doi.org/10.1073/pnas.0609810104 2013-08-31T16:02:41Z Constraining the topography of the inner-core boundary is important for studies of core–mantle coupling and the generation of the geodynamo. We present evidence for significant temporal variability in the amplitude of the inner core reflected phase PKiKP for an exceptionally high-quality earthquake doublet, observed postcritically at the short-period Yellowknife seismic array (YK), which occurred in the South Sandwich Islands within a 10-year interval (1993/2003). This observation, complemented by data from several other doublets, indicates the presence of topography at the inner-core boundary, with a horizontal wavelength on the order of 10 km. Such topography could be sustained by small-scale convection at the top of the inner core and is compatible with a rate of super rotation of the inner core of ≈0.1–0.15° per year. In the absence of inner-core rotation, decadal scale temporal changes in the inner-core boundary topography would provide an upper bound on the viscosity at the top of the inner core. Text South Sandwich Islands Yellowknife PubMed Central (PMC) Doublets ENVELOPE(98.667,98.667,-66.417,-66.417) Sandwich Islands South Sandwich Islands Yellowknife Proceedings of the National Academy of Sciences 104 1 31 35 |
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PubMed Central (PMC) |
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English |
topic |
Physical Sciences |
spellingShingle |
Physical Sciences Cao, Aimin Masson, Yder Romanowicz, Barbara Short wavelength topography on the inner-core boundary |
topic_facet |
Physical Sciences |
description |
Constraining the topography of the inner-core boundary is important for studies of core–mantle coupling and the generation of the geodynamo. We present evidence for significant temporal variability in the amplitude of the inner core reflected phase PKiKP for an exceptionally high-quality earthquake doublet, observed postcritically at the short-period Yellowknife seismic array (YK), which occurred in the South Sandwich Islands within a 10-year interval (1993/2003). This observation, complemented by data from several other doublets, indicates the presence of topography at the inner-core boundary, with a horizontal wavelength on the order of 10 km. Such topography could be sustained by small-scale convection at the top of the inner core and is compatible with a rate of super rotation of the inner core of ≈0.1–0.15° per year. In the absence of inner-core rotation, decadal scale temporal changes in the inner-core boundary topography would provide an upper bound on the viscosity at the top of the inner core. |
format |
Text |
author |
Cao, Aimin Masson, Yder Romanowicz, Barbara |
author_facet |
Cao, Aimin Masson, Yder Romanowicz, Barbara |
author_sort |
Cao, Aimin |
title |
Short wavelength topography on the inner-core boundary |
title_short |
Short wavelength topography on the inner-core boundary |
title_full |
Short wavelength topography on the inner-core boundary |
title_fullStr |
Short wavelength topography on the inner-core boundary |
title_full_unstemmed |
Short wavelength topography on the inner-core boundary |
title_sort |
short wavelength topography on the inner-core boundary |
publisher |
National Academy of Sciences |
publishDate |
2007 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1765456 http://www.ncbi.nlm.nih.gov/pubmed/17190798 https://doi.org/10.1073/pnas.0609810104 |
long_lat |
ENVELOPE(98.667,98.667,-66.417,-66.417) |
geographic |
Doublets Sandwich Islands South Sandwich Islands Yellowknife |
geographic_facet |
Doublets Sandwich Islands South Sandwich Islands Yellowknife |
genre |
South Sandwich Islands Yellowknife |
genre_facet |
South Sandwich Islands Yellowknife |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1765456 http://www.ncbi.nlm.nih.gov/pubmed/17190798 http://dx.doi.org/10.1073/pnas.0609810104 |
op_rights |
© 2006 by The National Academy of Sciences of the USA |
op_doi |
https://doi.org/10.1073/pnas.0609810104 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
104 |
container_issue |
1 |
container_start_page |
31 |
op_container_end_page |
35 |
_version_ |
1766203585195933696 |