Measuring seismic attenuation in polar firn: method and application to Korff Ice Rise, West Antarctica
Abstract We present seismic measurements of the firn column at Korff Ice Rise, West Antarctica, including measurements of compressional-wave velocity and attenuation. We describe a modified spectral-ratio method of measuring the seismic quality factor ( Q ) based on analysis of diving waves, which,...
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Cambridge University Press (CUP)
2023
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Online Access: | http://dx.doi.org/10.1017/jog.2023.82 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143023000825 |
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crcambridgeupr:10.1017/jog.2023.82 2024-09-09T19:02:59+00:00 Measuring seismic attenuation in polar firn: method and application to Korff Ice Rise, West Antarctica Agnew, Ronan S. Clark, Roger A. Booth, Adam D. Brisbourne, Alex M. Smith, Andrew M. Natural Environment Research Council British Antarctic Survey 2023 http://dx.doi.org/10.1017/jog.2023.82 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143023000825 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Journal of Glaciology page 1-12 ISSN 0022-1430 1727-5652 journal-article 2023 crcambridgeupr https://doi.org/10.1017/jog.2023.82 2024-07-17T04:04:15Z Abstract We present seismic measurements of the firn column at Korff Ice Rise, West Antarctica, including measurements of compressional-wave velocity and attenuation. We describe a modified spectral-ratio method of measuring the seismic quality factor ( Q ) based on analysis of diving waves, which, combined with a stochastic method of error propagation, enables us to characterise the attenuative structure of firn in greater detail than has previously been possible. Q increases from 56 ± 23 in the uppermost 12 m to 570 ± 450 between 55 and 77 m depth. We corroborate our method with consistent measurements obtained via primary reflection, multiple, source ghost, and critically refracted waves. Using the primary reflection and its ghost, we find Q = 53 ± 20 in the uppermost 20 m of firn. From the critical refraction, we find Q = 640 ± 400 at 90 m depth. Our method aids the understanding of the seismic structure of firn and benefits characterisation of deeper glaciological targets, providing an alternative means of correcting seismic reflection amplitudes in cases where conventional methods of Q correction may be impossible. Article in Journal/Newspaper Antarc* Antarctica Journal of Glaciology West Antarctica Cambridge University Press Korff Ice Rise ENVELOPE(-70.000,-70.000,-79.000,-79.000) West Antarctica Journal of Glaciology 1 12 |
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Open Polar |
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Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Abstract We present seismic measurements of the firn column at Korff Ice Rise, West Antarctica, including measurements of compressional-wave velocity and attenuation. We describe a modified spectral-ratio method of measuring the seismic quality factor ( Q ) based on analysis of diving waves, which, combined with a stochastic method of error propagation, enables us to characterise the attenuative structure of firn in greater detail than has previously been possible. Q increases from 56 ± 23 in the uppermost 12 m to 570 ± 450 between 55 and 77 m depth. We corroborate our method with consistent measurements obtained via primary reflection, multiple, source ghost, and critically refracted waves. Using the primary reflection and its ghost, we find Q = 53 ± 20 in the uppermost 20 m of firn. From the critical refraction, we find Q = 640 ± 400 at 90 m depth. Our method aids the understanding of the seismic structure of firn and benefits characterisation of deeper glaciological targets, providing an alternative means of correcting seismic reflection amplitudes in cases where conventional methods of Q correction may be impossible. |
author2 |
Natural Environment Research Council British Antarctic Survey |
format |
Article in Journal/Newspaper |
author |
Agnew, Ronan S. Clark, Roger A. Booth, Adam D. Brisbourne, Alex M. Smith, Andrew M. |
spellingShingle |
Agnew, Ronan S. Clark, Roger A. Booth, Adam D. Brisbourne, Alex M. Smith, Andrew M. Measuring seismic attenuation in polar firn: method and application to Korff Ice Rise, West Antarctica |
author_facet |
Agnew, Ronan S. Clark, Roger A. Booth, Adam D. Brisbourne, Alex M. Smith, Andrew M. |
author_sort |
Agnew, Ronan S. |
title |
Measuring seismic attenuation in polar firn: method and application to Korff Ice Rise, West Antarctica |
title_short |
Measuring seismic attenuation in polar firn: method and application to Korff Ice Rise, West Antarctica |
title_full |
Measuring seismic attenuation in polar firn: method and application to Korff Ice Rise, West Antarctica |
title_fullStr |
Measuring seismic attenuation in polar firn: method and application to Korff Ice Rise, West Antarctica |
title_full_unstemmed |
Measuring seismic attenuation in polar firn: method and application to Korff Ice Rise, West Antarctica |
title_sort |
measuring seismic attenuation in polar firn: method and application to korff ice rise, west antarctica |
publisher |
Cambridge University Press (CUP) |
publishDate |
2023 |
url |
http://dx.doi.org/10.1017/jog.2023.82 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143023000825 |
long_lat |
ENVELOPE(-70.000,-70.000,-79.000,-79.000) |
geographic |
Korff Ice Rise West Antarctica |
geographic_facet |
Korff Ice Rise West Antarctica |
genre |
Antarc* Antarctica Journal of Glaciology West Antarctica |
genre_facet |
Antarc* Antarctica Journal of Glaciology West Antarctica |
op_source |
Journal of Glaciology page 1-12 ISSN 0022-1430 1727-5652 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2023.82 |
container_title |
Journal of Glaciology |
container_start_page |
1 |
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12 |
_version_ |
1809817004696141824 |