The existence of an inner core super-rotation questioned by teleseismic doublets
International audience The first evidence for a differential rotation of the Earth's inner core with respect to the mantle comes from the detection of a variation, over 30 years, of the differential travel time anomalies of seismic core phases [Song, X., Richards, P.G., 1996. Seismological evid...
Published in: | Physics of the Earth and Planetary Interiors |
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Main Authors: | , , |
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Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2000
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Online Access: | https://insu.hal.science/insu-03606317 https://doi.org/10.1016/S0031-9201(99)00129-6 |
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[SDU]Sciences of the Universe [physics] |
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[SDU]Sciences of the Universe [physics] Poupinet, Georges Souriau, Annie Coutant, Olivier The existence of an inner core super-rotation questioned by teleseismic doublets |
topic_facet |
[SDU]Sciences of the Universe [physics] |
description |
International audience The first evidence for a differential rotation of the Earth's inner core with respect to the mantle comes from the detection of a variation, over 30 years, of the differential travel time anomalies of seismic core phases [Song, X., Richards, P.G., 1996. Seismological evidence for differential rotation of the Earth's inner core. Nature, 382, 221-224]. The comparison of teleseismic doublets provides a powerful means to measure such differential travel times and to test their temporal variation. Contrary to direct measurements of differential travel times, this technique does not require to have an accurate location of the seismic events. This method is first checked on examples of doublets for which no differential travel time is expected. These tests allow us to point out the difficulties, such as polarity reversals, which may be encountered in the use of the doublet method. It is then applied to deep Tonga events recorded in France and to the South Sandwich Islands events recorded at station College (COL), Alaska, which led Song and Richards to propose an inner core rotation. For the first path, we find no time variation, in agreement with previous studies. For the path from South Sandwich Island to COL, the doublet analysis shows that no significant temporal change in PKP travel time can be detected within the resolution of the method, which is about 0.05 s. The variation of the residuals observed by Song and Richards, about 0.3 s over 30 years, is in a large extent ascribable to hypocenter mislocations. Consequently, present seismological observations do not detect the inner core differential rotation because, if it exists, it is smaller than about 0.2°/year, the present detection capacity of seismology. |
author2 |
Laboratoire de Géophysique Interne et Tectonophysique (LGIT) Observatoire des Sciences de l'Univers de Grenoble (OSUG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Central des Ponts et Chaussées (LCPC)-Centre National de la Recherche Scientifique (CNRS) Services communs OMP (UMS 831) Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Poupinet, Georges Souriau, Annie Coutant, Olivier |
author_facet |
Poupinet, Georges Souriau, Annie Coutant, Olivier |
author_sort |
Poupinet, Georges |
title |
The existence of an inner core super-rotation questioned by teleseismic doublets |
title_short |
The existence of an inner core super-rotation questioned by teleseismic doublets |
title_full |
The existence of an inner core super-rotation questioned by teleseismic doublets |
title_fullStr |
The existence of an inner core super-rotation questioned by teleseismic doublets |
title_full_unstemmed |
The existence of an inner core super-rotation questioned by teleseismic doublets |
title_sort |
existence of an inner core super-rotation questioned by teleseismic doublets |
publisher |
HAL CCSD |
publishDate |
2000 |
url |
https://insu.hal.science/insu-03606317 https://doi.org/10.1016/S0031-9201(99)00129-6 |
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ENVELOPE(98.667,98.667,-66.417,-66.417) ENVELOPE(7.990,7.990,63.065,63.065) |
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Doublets Sandwich Islands South Sandwich Islands Tonga |
geographic_facet |
Doublets Sandwich Islands South Sandwich Islands Tonga |
genre |
South Sandwich Islands Alaska |
genre_facet |
South Sandwich Islands Alaska |
op_source |
Physics of the Earth and Planetary Interiors https://insu.hal.science/insu-03606317 Physics of the Earth and Planetary Interiors, 2000, 118, pp.77-88. ⟨10.1016/S0031-9201(99)00129-6⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/S0031-9201(99)00129-6 insu-03606317 https://insu.hal.science/insu-03606317 BIBCODE: 2000PEPI.118.77P doi:10.1016/S0031-9201(99)00129-6 |
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https://doi.org/10.1016/S0031-9201(99)00129-6 |
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Physics of the Earth and Planetary Interiors |
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118 |
container_issue |
1-2 |
container_start_page |
77 |
op_container_end_page |
88 |
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1786200256595099648 |
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ftccsdartic:oai:HAL:insu-03606317v1 2023-12-24T10:24:58+01:00 The existence of an inner core super-rotation questioned by teleseismic doublets Poupinet, Georges Souriau, Annie Coutant, Olivier Laboratoire de Géophysique Interne et Tectonophysique (LGIT) Observatoire des Sciences de l'Univers de Grenoble (OSUG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Central des Ponts et Chaussées (LCPC)-Centre National de la Recherche Scientifique (CNRS) Services communs OMP (UMS 831) Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) 2000 https://insu.hal.science/insu-03606317 https://doi.org/10.1016/S0031-9201(99)00129-6 en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.1016/S0031-9201(99)00129-6 insu-03606317 https://insu.hal.science/insu-03606317 BIBCODE: 2000PEPI.118.77P doi:10.1016/S0031-9201(99)00129-6 Physics of the Earth and Planetary Interiors https://insu.hal.science/insu-03606317 Physics of the Earth and Planetary Interiors, 2000, 118, pp.77-88. ⟨10.1016/S0031-9201(99)00129-6⟩ [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2000 ftccsdartic https://doi.org/10.1016/S0031-9201(99)00129-6 2023-11-26T00:12:40Z International audience The first evidence for a differential rotation of the Earth's inner core with respect to the mantle comes from the detection of a variation, over 30 years, of the differential travel time anomalies of seismic core phases [Song, X., Richards, P.G., 1996. Seismological evidence for differential rotation of the Earth's inner core. Nature, 382, 221-224]. The comparison of teleseismic doublets provides a powerful means to measure such differential travel times and to test their temporal variation. Contrary to direct measurements of differential travel times, this technique does not require to have an accurate location of the seismic events. This method is first checked on examples of doublets for which no differential travel time is expected. These tests allow us to point out the difficulties, such as polarity reversals, which may be encountered in the use of the doublet method. It is then applied to deep Tonga events recorded in France and to the South Sandwich Islands events recorded at station College (COL), Alaska, which led Song and Richards to propose an inner core rotation. For the first path, we find no time variation, in agreement with previous studies. For the path from South Sandwich Island to COL, the doublet analysis shows that no significant temporal change in PKP travel time can be detected within the resolution of the method, which is about 0.05 s. The variation of the residuals observed by Song and Richards, about 0.3 s over 30 years, is in a large extent ascribable to hypocenter mislocations. Consequently, present seismological observations do not detect the inner core differential rotation because, if it exists, it is smaller than about 0.2°/year, the present detection capacity of seismology. Article in Journal/Newspaper South Sandwich Islands Alaska Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Doublets ENVELOPE(98.667,98.667,-66.417,-66.417) Sandwich Islands South Sandwich Islands Tonga ENVELOPE(7.990,7.990,63.065,63.065) Physics of the Earth and Planetary Interiors 118 1-2 77 88 |