Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica
We use seismic refraction data to investigate the firn structure across a suture zone on the Amery Ice Shelf, East Antarctica, and the possible role of glacier dynamics in firn evolution. In the downstream direction, the data reveal decreasing compressional-wave velocities and increasing penetration...
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Cambridge University Press
2021
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ftdoajarticles:oai:doaj.org/article:035ff35fdafa4be8acf5922e5ff11432 2023-05-15T13:22:03+02:00 Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica Hannes Hollmann Adam Treverrow Leo E. Peters Anya M. Reading Bernd Kulessa 2021-10-01T00:00:00Z https://doi.org/10.1017/jog.2021.21 https://doaj.org/article/035ff35fdafa4be8acf5922e5ff11432 EN eng Cambridge University Press https://www.cambridge.org/core/product/identifier/S0022143021000216/type/journal_article https://doaj.org/toc/0022-1430 https://doaj.org/toc/1727-5652 doi:10.1017/jog.2021.21 0022-1430 1727-5652 https://doaj.org/article/035ff35fdafa4be8acf5922e5ff11432 Journal of Glaciology, Vol 67, Pp 777-787 (2021) Polar firn seismics snow mechanics Environmental sciences GE1-350 Meteorology. Climatology QC851-999 article 2021 ftdoajarticles https://doi.org/10.1017/jog.2021.21 2023-03-12T01:30:57Z We use seismic refraction data to investigate the firn structure across a suture zone on the Amery Ice Shelf, East Antarctica, and the possible role of glacier dynamics in firn evolution. In the downstream direction, the data reveal decreasing compressional-wave velocities and increasing penetration depth of the propagating wave in the firn layer, consistent with $\sim$1 m firn thickening every 6 km. The boundary between the Lambert Glacier unit to the west and a major suture zone and the Mawson Escarpment Ice Stream unit to the east, is marked by differences in firn thicknesses, compressional-wave velocities and seismic anisotropy in the across-flow direction. The latter does not contradict the presence of a single-maximum crystal orientation fabric oriented 45–$90^{\circ }$ away from the flow direction. This is consistent with the presence of transverse simple shear governing the region's underlying ice flow regime, in association with elevated strain along the suture zone. The confirmation and quantification of the implied dynamic coupling between firn and the underlying ice requires integration of future seismic refraction, coring and modelling studies. Because firn is estimated to cover $\sim$98% of the Antarctic continent any such coupling may have widespread relevance to ice-sheet evolution and flow. Article in Journal/Newspaper Amery Ice Shelf Antarc* Antarctic Antarctica East Antarctica Ice Sheet Ice Shelf Journal of Glaciology Lambert Glacier Directory of Open Access Journals: DOAJ Articles Amery ENVELOPE(-94.063,-94.063,56.565,56.565) Amery Ice Shelf ENVELOPE(71.000,71.000,-69.750,-69.750) Antarctic East Antarctica Lambert Glacier ENVELOPE(67.490,67.490,-73.065,-73.065) Mawson Escarpment ENVELOPE(68.167,68.167,-73.083,-73.083) The Antarctic Journal of Glaciology 67 265 777 787 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Polar firn seismics snow mechanics Environmental sciences GE1-350 Meteorology. Climatology QC851-999 |
spellingShingle |
Polar firn seismics snow mechanics Environmental sciences GE1-350 Meteorology. Climatology QC851-999 Hannes Hollmann Adam Treverrow Leo E. Peters Anya M. Reading Bernd Kulessa Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica |
topic_facet |
Polar firn seismics snow mechanics Environmental sciences GE1-350 Meteorology. Climatology QC851-999 |
description |
We use seismic refraction data to investigate the firn structure across a suture zone on the Amery Ice Shelf, East Antarctica, and the possible role of glacier dynamics in firn evolution. In the downstream direction, the data reveal decreasing compressional-wave velocities and increasing penetration depth of the propagating wave in the firn layer, consistent with $\sim$1 m firn thickening every 6 km. The boundary between the Lambert Glacier unit to the west and a major suture zone and the Mawson Escarpment Ice Stream unit to the east, is marked by differences in firn thicknesses, compressional-wave velocities and seismic anisotropy in the across-flow direction. The latter does not contradict the presence of a single-maximum crystal orientation fabric oriented 45–$90^{\circ }$ away from the flow direction. This is consistent with the presence of transverse simple shear governing the region's underlying ice flow regime, in association with elevated strain along the suture zone. The confirmation and quantification of the implied dynamic coupling between firn and the underlying ice requires integration of future seismic refraction, coring and modelling studies. Because firn is estimated to cover $\sim$98% of the Antarctic continent any such coupling may have widespread relevance to ice-sheet evolution and flow. |
format |
Article in Journal/Newspaper |
author |
Hannes Hollmann Adam Treverrow Leo E. Peters Anya M. Reading Bernd Kulessa |
author_facet |
Hannes Hollmann Adam Treverrow Leo E. Peters Anya M. Reading Bernd Kulessa |
author_sort |
Hannes Hollmann |
title |
Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica |
title_short |
Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica |
title_full |
Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica |
title_fullStr |
Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica |
title_full_unstemmed |
Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica |
title_sort |
seismic observations of a complex firn structure across the amery ice shelf, east antarctica |
publisher |
Cambridge University Press |
publishDate |
2021 |
url |
https://doi.org/10.1017/jog.2021.21 https://doaj.org/article/035ff35fdafa4be8acf5922e5ff11432 |
long_lat |
ENVELOPE(-94.063,-94.063,56.565,56.565) ENVELOPE(71.000,71.000,-69.750,-69.750) ENVELOPE(67.490,67.490,-73.065,-73.065) ENVELOPE(68.167,68.167,-73.083,-73.083) |
geographic |
Amery Amery Ice Shelf Antarctic East Antarctica Lambert Glacier Mawson Escarpment The Antarctic |
geographic_facet |
Amery Amery Ice Shelf Antarctic East Antarctica Lambert Glacier Mawson Escarpment The Antarctic |
genre |
Amery Ice Shelf Antarc* Antarctic Antarctica East Antarctica Ice Sheet Ice Shelf Journal of Glaciology Lambert Glacier |
genre_facet |
Amery Ice Shelf Antarc* Antarctic Antarctica East Antarctica Ice Sheet Ice Shelf Journal of Glaciology Lambert Glacier |
op_source |
Journal of Glaciology, Vol 67, Pp 777-787 (2021) |
op_relation |
https://www.cambridge.org/core/product/identifier/S0022143021000216/type/journal_article https://doaj.org/toc/0022-1430 https://doaj.org/toc/1727-5652 doi:10.1017/jog.2021.21 0022-1430 1727-5652 https://doaj.org/article/035ff35fdafa4be8acf5922e5ff11432 |
op_doi |
https://doi.org/10.1017/jog.2021.21 |
container_title |
Journal of Glaciology |
container_volume |
67 |
container_issue |
265 |
container_start_page |
777 |
op_container_end_page |
787 |
_version_ |
1766363036186050560 |