Measuring the thickness and Young’s modulus of the ice pack with DAS, a test case on a frozen mountain lake
SUMMARY We explored the potential of fibre optics coupled with distributed acoustic sensing (DAS) to measure the thickness and Young’s modulus of an ice layer, using the properties of guided seismic waves. During two winter seasons (2020 and 2021), an optical fibre was deployed over one of the froze...
Published in: | Geophysical Journal International |
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Oxford University Press (OUP)
2022
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Online Access: | http://dx.doi.org/10.1093/gji/ggac504 https://academic.oup.com/gji/advance-article-pdf/doi/10.1093/gji/ggac504/48360091/ggac504.pdf https://academic.oup.com/gji/article-pdf/233/2/1166/48755900/ggac504.pdf |
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croxfordunivpr:10.1093/gji/ggac504 2024-04-07T07:53:12+00:00 Measuring the thickness and Young’s modulus of the ice pack with DAS, a test case on a frozen mountain lake Nziengui-Bâ, Destin Coutant, Olivier Moreau, Ludovic Boué, Pierre Agence Nationale de la Recherche Auvergne-Rhône-Alpes region 2022 http://dx.doi.org/10.1093/gji/ggac504 https://academic.oup.com/gji/advance-article-pdf/doi/10.1093/gji/ggac504/48360091/ggac504.pdf https://academic.oup.com/gji/article-pdf/233/2/1166/48755900/ggac504.pdf en eng Oxford University Press (OUP) https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model Geophysical Journal International volume 233, issue 2, page 1166-1177 ISSN 0956-540X 1365-246X Geochemistry and Petrology Geophysics journal-article 2022 croxfordunivpr https://doi.org/10.1093/gji/ggac504 2024-03-08T02:59:40Z SUMMARY We explored the potential of fibre optics coupled with distributed acoustic sensing (DAS) to measure the thickness and Young’s modulus of an ice layer, using the properties of guided seismic waves. During two winter seasons (2020 and 2021), an optical fibre was deployed over one of the frozen Roberts Mountain lakes (at 2400 m a.s.l) near Grenoble (France) and we measured both the continuous ambient seismic noise as well as signals generated by active sources (hammer), with a DAS interrogator. Following a Bayesian scheme, we inverted the dispersion curves of longitudinal and flexural guided waves retrieved from the analysis of active shot gathers and obtained Young’s modulus E = 3.4 ± 0.1 GPa and ice thickness h = 47 ± 1 cm from the second-year data. The ice thickness was consistent with field measurements. Field observations of porous and/or fracture ice may explain the relatively low effective Young’s modulus (relative to pure ice), which may also be affected by a snow layer not included in the model. The drastic improvements in the inversion results between the two years are related to better coupling conditions (drone deployment before early freezing), more appropriate acquisition parameters (2 m gauge length), and the upper snow layers (less thick and less heterogeneous in the second year). Moreover, we were able to use the non-dispersive low-frequency noise associated with gravity waves to estimate the lake depth H = 5 m which is compatible with independent observations. The use of DAS to record guided seismic waves could then appear as a relevant tool for monitoring environments like floating ice shelves and sea ice. Article in Journal/Newspaper ice pack Ice Shelves Sea ice Oxford University Press Geophysical Journal International 233 2 1166 1177 |
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Open Polar |
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Oxford University Press |
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croxfordunivpr |
language |
English |
topic |
Geochemistry and Petrology Geophysics |
spellingShingle |
Geochemistry and Petrology Geophysics Nziengui-Bâ, Destin Coutant, Olivier Moreau, Ludovic Boué, Pierre Measuring the thickness and Young’s modulus of the ice pack with DAS, a test case on a frozen mountain lake |
topic_facet |
Geochemistry and Petrology Geophysics |
description |
SUMMARY We explored the potential of fibre optics coupled with distributed acoustic sensing (DAS) to measure the thickness and Young’s modulus of an ice layer, using the properties of guided seismic waves. During two winter seasons (2020 and 2021), an optical fibre was deployed over one of the frozen Roberts Mountain lakes (at 2400 m a.s.l) near Grenoble (France) and we measured both the continuous ambient seismic noise as well as signals generated by active sources (hammer), with a DAS interrogator. Following a Bayesian scheme, we inverted the dispersion curves of longitudinal and flexural guided waves retrieved from the analysis of active shot gathers and obtained Young’s modulus E = 3.4 ± 0.1 GPa and ice thickness h = 47 ± 1 cm from the second-year data. The ice thickness was consistent with field measurements. Field observations of porous and/or fracture ice may explain the relatively low effective Young’s modulus (relative to pure ice), which may also be affected by a snow layer not included in the model. The drastic improvements in the inversion results between the two years are related to better coupling conditions (drone deployment before early freezing), more appropriate acquisition parameters (2 m gauge length), and the upper snow layers (less thick and less heterogeneous in the second year). Moreover, we were able to use the non-dispersive low-frequency noise associated with gravity waves to estimate the lake depth H = 5 m which is compatible with independent observations. The use of DAS to record guided seismic waves could then appear as a relevant tool for monitoring environments like floating ice shelves and sea ice. |
author2 |
Agence Nationale de la Recherche Auvergne-Rhône-Alpes region |
format |
Article in Journal/Newspaper |
author |
Nziengui-Bâ, Destin Coutant, Olivier Moreau, Ludovic Boué, Pierre |
author_facet |
Nziengui-Bâ, Destin Coutant, Olivier Moreau, Ludovic Boué, Pierre |
author_sort |
Nziengui-Bâ, Destin |
title |
Measuring the thickness and Young’s modulus of the ice pack with DAS, a test case on a frozen mountain lake |
title_short |
Measuring the thickness and Young’s modulus of the ice pack with DAS, a test case on a frozen mountain lake |
title_full |
Measuring the thickness and Young’s modulus of the ice pack with DAS, a test case on a frozen mountain lake |
title_fullStr |
Measuring the thickness and Young’s modulus of the ice pack with DAS, a test case on a frozen mountain lake |
title_full_unstemmed |
Measuring the thickness and Young’s modulus of the ice pack with DAS, a test case on a frozen mountain lake |
title_sort |
measuring the thickness and young’s modulus of the ice pack with das, a test case on a frozen mountain lake |
publisher |
Oxford University Press (OUP) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1093/gji/ggac504 https://academic.oup.com/gji/advance-article-pdf/doi/10.1093/gji/ggac504/48360091/ggac504.pdf https://academic.oup.com/gji/article-pdf/233/2/1166/48755900/ggac504.pdf |
genre |
ice pack Ice Shelves Sea ice |
genre_facet |
ice pack Ice Shelves Sea ice |
op_source |
Geophysical Journal International volume 233, issue 2, page 1166-1177 ISSN 0956-540X 1365-246X |
op_rights |
https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model |
op_doi |
https://doi.org/10.1093/gji/ggac504 |
container_title |
Geophysical Journal International |
container_volume |
233 |
container_issue |
2 |
container_start_page |
1166 |
op_container_end_page |
1177 |
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1795668868456251392 |