Narrowband signals recorded near a moulin that are not moulin tremor: a cautionary short note
Abstract Geophysicists that deploy seismic sensors in ablation zones of glaciers and ice sheets to record glaciogenic signatures can confront recording challenges caused by instrument melt-out or tilt. These challenges often require installing sensors in boreholes to delay melt-out, or securing sens...
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Online Access: | http://dx.doi.org/10.1017/aog.2019.23 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305519000235 |
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crcambridgeupr:10.1017/aog.2019.23 2024-09-15T17:39:52+00:00 Narrowband signals recorded near a moulin that are not moulin tremor: a cautionary short note Carmichael, Joshua D 2019 http://dx.doi.org/10.1017/aog.2019.23 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305519000235 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Annals of Glaciology volume 60, issue 79, page 231-237 ISSN 0260-3055 1727-5644 journal-article 2019 crcambridgeupr https://doi.org/10.1017/aog.2019.23 2024-08-28T04:03:23Z Abstract Geophysicists that deploy seismic sensors in ablation zones of glaciers and ice sheets to record glaciogenic signatures can confront recording challenges caused by instrument melt-out or tilt. These challenges often require installing sensors in boreholes to delay melt-out, or securing sensors to structures that improve coupling. We show that some of these structures that were buried near a moulin at a snow-free site in the ablation zone of the Western Greenland Ice Sheet resonated as they became exposed, and caused their geophones to record temporally evolving, narrowband signals that mimic features of glaciogenic sources like moulin tremor. We quantify these artifacts with a mechanical model that shows instruments undergo structural resonance as they melt-out, at exposure rates that we predict from an ablation model (RACMO). These models reproduce general spectral features in our data, and enable us to estimate what instrument exposure reduces ice-to-sensor coupling enough to prevent icequake detection. Last, we use our resonance data to quantitatively measure how narrowband signals that originate from either artificial or glaciogenic sources will reduce the ability of certain waveform detectors (correlators) to capture transient seismic events, even if sensors remain coupled. Article in Journal/Newspaper Annals of Glaciology Greenland Ice Sheet Cambridge University Press Annals of Glaciology 60 79 231 237 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract Geophysicists that deploy seismic sensors in ablation zones of glaciers and ice sheets to record glaciogenic signatures can confront recording challenges caused by instrument melt-out or tilt. These challenges often require installing sensors in boreholes to delay melt-out, or securing sensors to structures that improve coupling. We show that some of these structures that were buried near a moulin at a snow-free site in the ablation zone of the Western Greenland Ice Sheet resonated as they became exposed, and caused their geophones to record temporally evolving, narrowband signals that mimic features of glaciogenic sources like moulin tremor. We quantify these artifacts with a mechanical model that shows instruments undergo structural resonance as they melt-out, at exposure rates that we predict from an ablation model (RACMO). These models reproduce general spectral features in our data, and enable us to estimate what instrument exposure reduces ice-to-sensor coupling enough to prevent icequake detection. Last, we use our resonance data to quantitatively measure how narrowband signals that originate from either artificial or glaciogenic sources will reduce the ability of certain waveform detectors (correlators) to capture transient seismic events, even if sensors remain coupled. |
format |
Article in Journal/Newspaper |
author |
Carmichael, Joshua D |
spellingShingle |
Carmichael, Joshua D Narrowband signals recorded near a moulin that are not moulin tremor: a cautionary short note |
author_facet |
Carmichael, Joshua D |
author_sort |
Carmichael, Joshua D |
title |
Narrowband signals recorded near a moulin that are not moulin tremor: a cautionary short note |
title_short |
Narrowband signals recorded near a moulin that are not moulin tremor: a cautionary short note |
title_full |
Narrowband signals recorded near a moulin that are not moulin tremor: a cautionary short note |
title_fullStr |
Narrowband signals recorded near a moulin that are not moulin tremor: a cautionary short note |
title_full_unstemmed |
Narrowband signals recorded near a moulin that are not moulin tremor: a cautionary short note |
title_sort |
narrowband signals recorded near a moulin that are not moulin tremor: a cautionary short note |
publisher |
Cambridge University Press (CUP) |
publishDate |
2019 |
url |
http://dx.doi.org/10.1017/aog.2019.23 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305519000235 |
genre |
Annals of Glaciology Greenland Ice Sheet |
genre_facet |
Annals of Glaciology Greenland Ice Sheet |
op_source |
Annals of Glaciology volume 60, issue 79, page 231-237 ISSN 0260-3055 1727-5644 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/aog.2019.23 |
container_title |
Annals of Glaciology |
container_volume |
60 |
container_issue |
79 |
container_start_page |
231 |
op_container_end_page |
237 |
_version_ |
1810483070414880768 |