Ambient high-frequency seismic surface waves in the firn column of central west Antarctica
Abstract Firn is the pervasive surface material across Antarctica, and its structures reflect its formation and history in response to environmental perturbations. In addition to the role of firn in thermally isolating underlying glacial ice, it defines near-surface elastic and density structure and...
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Online Access: | http://dx.doi.org/10.1017/jog.2021.135 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001350 |
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crcambridgeupr:10.1017/jog.2021.135 2024-09-15T17:45:39+00:00 Ambient high-frequency seismic surface waves in the firn column of central west Antarctica Chaput, Julien Aster, Rick Karplus, Marianne Nakata, Nori NSF-OPP 2022 http://dx.doi.org/10.1017/jog.2021.135 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001350 en eng Cambridge University Press (CUP) https://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 68, issue 270, page 785-798 ISSN 0022-1430 1727-5652 journal-article 2022 crcambridgeupr https://doi.org/10.1017/jog.2021.135 2024-08-21T04:02:54Z Abstract Firn is the pervasive surface material across Antarctica, and its structures reflect its formation and history in response to environmental perturbations. In addition to the role of firn in thermally isolating underlying glacial ice, it defines near-surface elastic and density structure and strongly influences high-frequency (> 5 Hz) seismic phenomena observed near the surface. We investigate high-frequency seismic data collected with an array of seismographs deployed on the West Antarctic Ice Sheet (WAIS) near WAIS Divide camp in January 2019. Cross-correlations of anthropogenic noise originating from the approximately 5 km-distant camp were constructed using a 1 km-diameter circular array of 22 seismographs. We distinguish three Rayleigh (elastic surface) wave modes at frequencies up to 50 Hz that exhibit systematic spatially varying particle motion characteristics. The horizontal-to-vertical ratio for the second mode shows a spatial pattern of peak frequencies that matches particle motion transitions for both the fundamental and second Rayleigh modes. This pattern is further evident in the appearance of narrow band spectral peaks. We find that shallow lateral structural variations are consistent with these observations, and model spectral peaks as Rayleigh wave amplifications within similarly scaled shallow basin-like structures delineated by the strong velocity and density gradients typical of Antarctic firn. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Journal of Glaciology West Antarctica Cambridge University Press Journal of Glaciology 1 14 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract Firn is the pervasive surface material across Antarctica, and its structures reflect its formation and history in response to environmental perturbations. In addition to the role of firn in thermally isolating underlying glacial ice, it defines near-surface elastic and density structure and strongly influences high-frequency (> 5 Hz) seismic phenomena observed near the surface. We investigate high-frequency seismic data collected with an array of seismographs deployed on the West Antarctic Ice Sheet (WAIS) near WAIS Divide camp in January 2019. Cross-correlations of anthropogenic noise originating from the approximately 5 km-distant camp were constructed using a 1 km-diameter circular array of 22 seismographs. We distinguish three Rayleigh (elastic surface) wave modes at frequencies up to 50 Hz that exhibit systematic spatially varying particle motion characteristics. The horizontal-to-vertical ratio for the second mode shows a spatial pattern of peak frequencies that matches particle motion transitions for both the fundamental and second Rayleigh modes. This pattern is further evident in the appearance of narrow band spectral peaks. We find that shallow lateral structural variations are consistent with these observations, and model spectral peaks as Rayleigh wave amplifications within similarly scaled shallow basin-like structures delineated by the strong velocity and density gradients typical of Antarctic firn. |
author2 |
NSF-OPP |
format |
Article in Journal/Newspaper |
author |
Chaput, Julien Aster, Rick Karplus, Marianne Nakata, Nori |
spellingShingle |
Chaput, Julien Aster, Rick Karplus, Marianne Nakata, Nori Ambient high-frequency seismic surface waves in the firn column of central west Antarctica |
author_facet |
Chaput, Julien Aster, Rick Karplus, Marianne Nakata, Nori |
author_sort |
Chaput, Julien |
title |
Ambient high-frequency seismic surface waves in the firn column of central west Antarctica |
title_short |
Ambient high-frequency seismic surface waves in the firn column of central west Antarctica |
title_full |
Ambient high-frequency seismic surface waves in the firn column of central west Antarctica |
title_fullStr |
Ambient high-frequency seismic surface waves in the firn column of central west Antarctica |
title_full_unstemmed |
Ambient high-frequency seismic surface waves in the firn column of central west Antarctica |
title_sort |
ambient high-frequency seismic surface waves in the firn column of central west antarctica |
publisher |
Cambridge University Press (CUP) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1017/jog.2021.135 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001350 |
genre |
Antarc* Antarctic Antarctica Ice Sheet Journal of Glaciology West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Journal of Glaciology West Antarctica |
op_source |
Journal of Glaciology volume 68, issue 270, page 785-798 ISSN 0022-1430 1727-5652 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2021.135 |
container_title |
Journal of Glaciology |
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1 |
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14 |
_version_ |
1810493537249132544 |