Not all icequakes are created equal: basal icequakes suggest diverse bed deformation mechanisms at Rutford Ice Stream, West Antarctica
Microseismicity, induced by the sliding of a glacier over its bed, can be used to characterize frictional properties of the ice‐bed interface, which are a key parameter controlling ice stream flow. We use naturally occurring seismicity to monitor spatiotemporally varying bed properties at Rutford Ic...
Published in: | Journal of Geophysical Research: Earth Surface |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Wiley
2021
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Online Access: | http://nora.nerc.ac.uk/id/eprint/529114/ https://nora.nerc.ac.uk/id/eprint/529114/1/2020JF006001.pdf https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JF006001 |
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ftnerc:oai:nora.nerc.ac.uk:529114 2023-05-15T13:41:45+02:00 Not all icequakes are created equal: basal icequakes suggest diverse bed deformation mechanisms at Rutford Ice Stream, West Antarctica Kufner, Sofia-Katerina Brisbourne, Alex M. Smith, Andrew M. Hudson, Thomas S. Murray, Tavi Schlegel, Rebecca Kendall, John M. Anandakrishnan, Sridhar Lee, Ian 2021-03-26 text http://nora.nerc.ac.uk/id/eprint/529114/ https://nora.nerc.ac.uk/id/eprint/529114/1/2020JF006001.pdf https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JF006001 en eng Wiley https://nora.nerc.ac.uk/id/eprint/529114/1/2020JF006001.pdf Kufner, Sofia-Katerina orcid:0000-0002-9687-5455 Brisbourne, Alex M. orcid:0000-0002-9887-7120 Smith, Andrew M. orcid:0000-0001-8577-482X Hudson, Thomas S.; Murray, Tavi; Schlegel, Rebecca; Kendall, John M.; Anandakrishnan, Sridhar; Lee, Ian. 2021 Not all icequakes are created equal: basal icequakes suggest diverse bed deformation mechanisms at Rutford Ice Stream, West Antarctica. Journal of Geophysical Research: Earth Surface, 126 (3), e2020JF006001. https://doi.org/10.1029/2020JF006001 <https://doi.org/10.1029/2020JF006001> cc_by_4 CC-BY Publication - Article PeerReviewed 2021 ftnerc https://doi.org/10.1029/2020JF006001 2023-02-04T19:51:26Z Microseismicity, induced by the sliding of a glacier over its bed, can be used to characterize frictional properties of the ice‐bed interface, which are a key parameter controlling ice stream flow. We use naturally occurring seismicity to monitor spatiotemporally varying bed properties at Rutford Ice Stream, West Antarctica. We locate 230000 micro‐earthquakes with local magnitudes from –2.0 to –0.3 using 90 days of recordings from a 35‐station seismic network located ∼40 km upstream of the grounding line. Events exclusively occur near the ice‐bed interface and indicate predominantly flow‐parallel stick‐slip. They mostly lie within a region of interpreted stiff till and along the likely stiffer part of mega‐scale glacial landforms. Within these regions, micro‐earthquakes occur in spatially (<100 m radius) and temporally (mostly 1‐5 days activity) restricted event‐clusters (up to 4000 events), which exhibit an increase, followed by a decrease, in event magnitude with time. This may indicate event triggering once activity is initiated. Although ocean tides modulate the surface ice flow velocity, we observe little periodic variation in overall event frequency over time and conclude that water content, bed topography and stiffness are the major factors controlling microseismicity. Based on variable rupture mechanisms and spatiotemporal characteristics, we suggest the event‐clusters relate to three end‐member types of bed deformation: (1) continuous creation and seismogenic destruction of small‐scale bed‐roughness, (2) ploughed clasts and (3) flow‐oblique deformation during landform‐formation or along bedrock outcrops. This indicates that multiple processes, simultaneously active during glacial sliding, can accommodate stick‐slip behaviour and that the bed continuously reorganizes. Article in Journal/Newspaper Antarc* Antarctica Antarctica Journal Rutford Ice Stream West Antarctica Natural Environment Research Council: NERC Open Research Archive West Antarctica Rutford ENVELOPE(-85.300,-85.300,-78.600,-78.600) Rutford Ice Stream ENVELOPE(-80.000,-80.000,-79.167,-79.167) Journal of Geophysical Research: Earth Surface 126 3 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Microseismicity, induced by the sliding of a glacier over its bed, can be used to characterize frictional properties of the ice‐bed interface, which are a key parameter controlling ice stream flow. We use naturally occurring seismicity to monitor spatiotemporally varying bed properties at Rutford Ice Stream, West Antarctica. We locate 230000 micro‐earthquakes with local magnitudes from –2.0 to –0.3 using 90 days of recordings from a 35‐station seismic network located ∼40 km upstream of the grounding line. Events exclusively occur near the ice‐bed interface and indicate predominantly flow‐parallel stick‐slip. They mostly lie within a region of interpreted stiff till and along the likely stiffer part of mega‐scale glacial landforms. Within these regions, micro‐earthquakes occur in spatially (<100 m radius) and temporally (mostly 1‐5 days activity) restricted event‐clusters (up to 4000 events), which exhibit an increase, followed by a decrease, in event magnitude with time. This may indicate event triggering once activity is initiated. Although ocean tides modulate the surface ice flow velocity, we observe little periodic variation in overall event frequency over time and conclude that water content, bed topography and stiffness are the major factors controlling microseismicity. Based on variable rupture mechanisms and spatiotemporal characteristics, we suggest the event‐clusters relate to three end‐member types of bed deformation: (1) continuous creation and seismogenic destruction of small‐scale bed‐roughness, (2) ploughed clasts and (3) flow‐oblique deformation during landform‐formation or along bedrock outcrops. This indicates that multiple processes, simultaneously active during glacial sliding, can accommodate stick‐slip behaviour and that the bed continuously reorganizes. |
format |
Article in Journal/Newspaper |
author |
Kufner, Sofia-Katerina Brisbourne, Alex M. Smith, Andrew M. Hudson, Thomas S. Murray, Tavi Schlegel, Rebecca Kendall, John M. Anandakrishnan, Sridhar Lee, Ian |
spellingShingle |
Kufner, Sofia-Katerina Brisbourne, Alex M. Smith, Andrew M. Hudson, Thomas S. Murray, Tavi Schlegel, Rebecca Kendall, John M. Anandakrishnan, Sridhar Lee, Ian Not all icequakes are created equal: basal icequakes suggest diverse bed deformation mechanisms at Rutford Ice Stream, West Antarctica |
author_facet |
Kufner, Sofia-Katerina Brisbourne, Alex M. Smith, Andrew M. Hudson, Thomas S. Murray, Tavi Schlegel, Rebecca Kendall, John M. Anandakrishnan, Sridhar Lee, Ian |
author_sort |
Kufner, Sofia-Katerina |
title |
Not all icequakes are created equal: basal icequakes suggest diverse bed deformation mechanisms at Rutford Ice Stream, West Antarctica |
title_short |
Not all icequakes are created equal: basal icequakes suggest diverse bed deformation mechanisms at Rutford Ice Stream, West Antarctica |
title_full |
Not all icequakes are created equal: basal icequakes suggest diverse bed deformation mechanisms at Rutford Ice Stream, West Antarctica |
title_fullStr |
Not all icequakes are created equal: basal icequakes suggest diverse bed deformation mechanisms at Rutford Ice Stream, West Antarctica |
title_full_unstemmed |
Not all icequakes are created equal: basal icequakes suggest diverse bed deformation mechanisms at Rutford Ice Stream, West Antarctica |
title_sort |
not all icequakes are created equal: basal icequakes suggest diverse bed deformation mechanisms at rutford ice stream, west antarctica |
publisher |
Wiley |
publishDate |
2021 |
url |
http://nora.nerc.ac.uk/id/eprint/529114/ https://nora.nerc.ac.uk/id/eprint/529114/1/2020JF006001.pdf https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JF006001 |
long_lat |
ENVELOPE(-85.300,-85.300,-78.600,-78.600) ENVELOPE(-80.000,-80.000,-79.167,-79.167) |
geographic |
West Antarctica Rutford Rutford Ice Stream |
geographic_facet |
West Antarctica Rutford Rutford Ice Stream |
genre |
Antarc* Antarctica Antarctica Journal Rutford Ice Stream West Antarctica |
genre_facet |
Antarc* Antarctica Antarctica Journal Rutford Ice Stream West Antarctica |
op_relation |
https://nora.nerc.ac.uk/id/eprint/529114/1/2020JF006001.pdf Kufner, Sofia-Katerina orcid:0000-0002-9687-5455 Brisbourne, Alex M. orcid:0000-0002-9887-7120 Smith, Andrew M. orcid:0000-0001-8577-482X Hudson, Thomas S.; Murray, Tavi; Schlegel, Rebecca; Kendall, John M.; Anandakrishnan, Sridhar; Lee, Ian. 2021 Not all icequakes are created equal: basal icequakes suggest diverse bed deformation mechanisms at Rutford Ice Stream, West Antarctica. Journal of Geophysical Research: Earth Surface, 126 (3), e2020JF006001. https://doi.org/10.1029/2020JF006001 <https://doi.org/10.1029/2020JF006001> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1029/2020JF006001 |
container_title |
Journal of Geophysical Research: Earth Surface |
container_volume |
126 |
container_issue |
3 |
_version_ |
1766157183726125056 |