Localised thickening and grounding of an Antarctic ice shelf from tidal triggering and sizing of cryoseismicity
We observe remarkably periodic patterns of seismicity rates and magnitudes at the Fimbul Ice Shelf, East Antarctica, correlating with the cycles of the ocean tide. Our analysis covers 19 years of continuous seismic recordings from Antarctic broadband stations. Seismicity commences abruptly during au...
Published in: | Earth and Planetary Science Letters |
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Language: | English |
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2018
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_3568892 2023-05-15T13:35:25+02:00 Localised thickening and grounding of an Antarctic ice shelf from tidal triggering and sizing of cryoseismicity Pirli, M. Hainzl, S. Schweitzer, J. Köhler, A. Dahm, T. 2018 application/pdf https://gfzpublic.gfz-potsdam.de/pubman/item/item_3568892 https://gfzpublic.gfz-potsdam.de/pubman/item/item_3568892_5/component/file_3613892/3568892.pdf eng eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2018.09.024 https://gfzpublic.gfz-potsdam.de/pubman/item/item_3568892 https://gfzpublic.gfz-potsdam.de/pubman/item/item_3568892_5/component/file_3613892/3568892.pdf info:eu-repo/semantics/openAccess Earth and Planetary Science Letters info:eu-repo/semantics/article 2018 ftgfzpotsdam https://doi.org/10.1016/j.epsl.2018.09.024 2022-09-14T05:56:48Z We observe remarkably periodic patterns of seismicity rates and magnitudes at the Fimbul Ice Shelf, East Antarctica, correlating with the cycles of the ocean tide. Our analysis covers 19 years of continuous seismic recordings from Antarctic broadband stations. Seismicity commences abruptly during austral summer 2011 at a location near the ocean front in a shallow water region. Dozens of highly repetitive events occur in semi-diurnal cycles, with magnitudes and rates fluctuating steadily with the tide. In contrast to the common unpredictability of earthquake magnitudes, the event magnitudes show deterministic trends within single cycles and strong correlations with spring tides and tide height. The events occur quasi-periodically and the highly constrained event sources migrate landwards during rising tide. We show that a simple, mechanical model can explain most of the observations. Our model assumes stick-slip motion on a patch of grounded ice shelf, which is forced by the variations of the ocean-tide height and ice flow. The well fitted observations give new insights into the general process of frictional triggering of earthquakes, while providing independent evidence of variations in ice shelf thickness and grounding. Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica Fimbul Ice Shelf Ice Shelf GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Antarctic East Antarctica Austral Fimbul Ice Shelf ENVELOPE(-0.500,-0.500,-70.750,-70.750) Earth and Planetary Science Letters 503 78 87 |
institution |
Open Polar |
collection |
GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
English |
description |
We observe remarkably periodic patterns of seismicity rates and magnitudes at the Fimbul Ice Shelf, East Antarctica, correlating with the cycles of the ocean tide. Our analysis covers 19 years of continuous seismic recordings from Antarctic broadband stations. Seismicity commences abruptly during austral summer 2011 at a location near the ocean front in a shallow water region. Dozens of highly repetitive events occur in semi-diurnal cycles, with magnitudes and rates fluctuating steadily with the tide. In contrast to the common unpredictability of earthquake magnitudes, the event magnitudes show deterministic trends within single cycles and strong correlations with spring tides and tide height. The events occur quasi-periodically and the highly constrained event sources migrate landwards during rising tide. We show that a simple, mechanical model can explain most of the observations. Our model assumes stick-slip motion on a patch of grounded ice shelf, which is forced by the variations of the ocean-tide height and ice flow. The well fitted observations give new insights into the general process of frictional triggering of earthquakes, while providing independent evidence of variations in ice shelf thickness and grounding. |
format |
Article in Journal/Newspaper |
author |
Pirli, M. Hainzl, S. Schweitzer, J. Köhler, A. Dahm, T. |
spellingShingle |
Pirli, M. Hainzl, S. Schweitzer, J. Köhler, A. Dahm, T. Localised thickening and grounding of an Antarctic ice shelf from tidal triggering and sizing of cryoseismicity |
author_facet |
Pirli, M. Hainzl, S. Schweitzer, J. Köhler, A. Dahm, T. |
author_sort |
Pirli, M. |
title |
Localised thickening and grounding of an Antarctic ice shelf from tidal triggering and sizing of cryoseismicity |
title_short |
Localised thickening and grounding of an Antarctic ice shelf from tidal triggering and sizing of cryoseismicity |
title_full |
Localised thickening and grounding of an Antarctic ice shelf from tidal triggering and sizing of cryoseismicity |
title_fullStr |
Localised thickening and grounding of an Antarctic ice shelf from tidal triggering and sizing of cryoseismicity |
title_full_unstemmed |
Localised thickening and grounding of an Antarctic ice shelf from tidal triggering and sizing of cryoseismicity |
title_sort |
localised thickening and grounding of an antarctic ice shelf from tidal triggering and sizing of cryoseismicity |
publishDate |
2018 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_3568892 https://gfzpublic.gfz-potsdam.de/pubman/item/item_3568892_5/component/file_3613892/3568892.pdf |
long_lat |
ENVELOPE(-0.500,-0.500,-70.750,-70.750) |
geographic |
Antarctic East Antarctica Austral Fimbul Ice Shelf |
geographic_facet |
Antarctic East Antarctica Austral Fimbul Ice Shelf |
genre |
Antarc* Antarctic Antarctica East Antarctica Fimbul Ice Shelf Ice Shelf |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Fimbul Ice Shelf Ice Shelf |
op_source |
Earth and Planetary Science Letters |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2018.09.024 https://gfzpublic.gfz-potsdam.de/pubman/item/item_3568892 https://gfzpublic.gfz-potsdam.de/pubman/item/item_3568892_5/component/file_3613892/3568892.pdf |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1016/j.epsl.2018.09.024 |
container_title |
Earth and Planetary Science Letters |
container_volume |
503 |
container_start_page |
78 |
op_container_end_page |
87 |
_version_ |
1766065378002206720 |