The influence of environmental microseismicity on detection and interpretation of small-magnitude events in a polar glacier setting
Abstract Glacial environments exhibit temporally variable microseismicity. To investigate how microseismicity influences event detection, we implement two noise-adaptive digital power detectors to process seismic data from Taylor Glacier, Antarctica. We add scaled icequake waveforms to the original...
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crcambridgeupr:10.1017/jog.2020.48 2024-03-03T08:37:54+00:00 The influence of environmental microseismicity on detection and interpretation of small-magnitude events in a polar glacier setting Carr, Chris G. Carmichael, Joshua D. Pettit, Erin C. Truffer, Martin 2020 http://dx.doi.org/10.1017/jog.2020.48 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143020000489 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 66, issue 259, page 790-806 ISSN 0022-1430 1727-5652 Earth-Surface Processes journal-article 2020 crcambridgeupr https://doi.org/10.1017/jog.2020.48 2024-02-08T08:44:47Z Abstract Glacial environments exhibit temporally variable microseismicity. To investigate how microseismicity influences event detection, we implement two noise-adaptive digital power detectors to process seismic data from Taylor Glacier, Antarctica. We add scaled icequake waveforms to the original data stream, run detectors on the hybrid data stream to estimate reliable detection magnitudes and compare analytical magnitudes predicted from an ice crack source model. We find that detection capability is influenced by environmental microseismicity for seismic events with source size comparable to thermal penetration depths. When event counts and minimum detectable event sizes change in the same direction (i.e. increase in event counts and minimum detectable event size), we interpret measured seismicity changes as ‘true’ seismicity changes rather than as changes in detection. Generally, one detector (two degree of freedom (2dof)) outperforms the other: it identifies more events, a more prominent summertime diurnal signal and maintains a higher detection capability. We conclude that real physical processes are responsible for the summertime diurnal inter-detector difference. One detector (3dof) identifies this process as environmental microseismicity; the other detector (2dof) identifies it as elevated waveform activity. Our analysis provides an example for minimizing detection biases and estimating source sizes when interpreting temporal seismicity patterns to better infer glacial seismogenic processes. Article in Journal/Newspaper Antarc* Antarctica Journal of Glaciology Taylor Glacier Cambridge University Press Taylor Glacier ENVELOPE(162.167,162.167,-77.733,-77.733) Journal of Glaciology 66 259 790 806 |
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Open Polar |
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Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
Earth-Surface Processes |
spellingShingle |
Earth-Surface Processes Carr, Chris G. Carmichael, Joshua D. Pettit, Erin C. Truffer, Martin The influence of environmental microseismicity on detection and interpretation of small-magnitude events in a polar glacier setting |
topic_facet |
Earth-Surface Processes |
description |
Abstract Glacial environments exhibit temporally variable microseismicity. To investigate how microseismicity influences event detection, we implement two noise-adaptive digital power detectors to process seismic data from Taylor Glacier, Antarctica. We add scaled icequake waveforms to the original data stream, run detectors on the hybrid data stream to estimate reliable detection magnitudes and compare analytical magnitudes predicted from an ice crack source model. We find that detection capability is influenced by environmental microseismicity for seismic events with source size comparable to thermal penetration depths. When event counts and minimum detectable event sizes change in the same direction (i.e. increase in event counts and minimum detectable event size), we interpret measured seismicity changes as ‘true’ seismicity changes rather than as changes in detection. Generally, one detector (two degree of freedom (2dof)) outperforms the other: it identifies more events, a more prominent summertime diurnal signal and maintains a higher detection capability. We conclude that real physical processes are responsible for the summertime diurnal inter-detector difference. One detector (3dof) identifies this process as environmental microseismicity; the other detector (2dof) identifies it as elevated waveform activity. Our analysis provides an example for minimizing detection biases and estimating source sizes when interpreting temporal seismicity patterns to better infer glacial seismogenic processes. |
format |
Article in Journal/Newspaper |
author |
Carr, Chris G. Carmichael, Joshua D. Pettit, Erin C. Truffer, Martin |
author_facet |
Carr, Chris G. Carmichael, Joshua D. Pettit, Erin C. Truffer, Martin |
author_sort |
Carr, Chris G. |
title |
The influence of environmental microseismicity on detection and interpretation of small-magnitude events in a polar glacier setting |
title_short |
The influence of environmental microseismicity on detection and interpretation of small-magnitude events in a polar glacier setting |
title_full |
The influence of environmental microseismicity on detection and interpretation of small-magnitude events in a polar glacier setting |
title_fullStr |
The influence of environmental microseismicity on detection and interpretation of small-magnitude events in a polar glacier setting |
title_full_unstemmed |
The influence of environmental microseismicity on detection and interpretation of small-magnitude events in a polar glacier setting |
title_sort |
influence of environmental microseismicity on detection and interpretation of small-magnitude events in a polar glacier setting |
publisher |
Cambridge University Press (CUP) |
publishDate |
2020 |
url |
http://dx.doi.org/10.1017/jog.2020.48 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143020000489 |
long_lat |
ENVELOPE(162.167,162.167,-77.733,-77.733) |
geographic |
Taylor Glacier |
geographic_facet |
Taylor Glacier |
genre |
Antarc* Antarctica Journal of Glaciology Taylor Glacier |
genre_facet |
Antarc* Antarctica Journal of Glaciology Taylor Glacier |
op_source |
Journal of Glaciology volume 66, issue 259, page 790-806 ISSN 0022-1430 1727-5652 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2020.48 |
container_title |
Journal of Glaciology |
container_volume |
66 |
container_issue |
259 |
container_start_page |
790 |
op_container_end_page |
806 |
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1792502735070822400 |