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Improved Estimation of Glacial‐Earthquake Size Through New Modeling of the Seismic Source

Kira G. Olsen, Meredith Nettles, L. Mac Cathles, Justin C. Burton, Tavi Murray Orcid Logo, Timothy James Orcid Logo

Journal of Geophysical Research: Earth Surface, Volume: 126, Issue: 12

Swansea University Authors: Tavi Murray Orcid Logo, Timothy James Orcid Logo

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DOI (Published version): 10.1029/2021jf006384

Abstract

The number of gigaton-sized iceberg-calving events occurring annually at Greenland glaciers is increasing, part of a larger trend of accelerating mass loss from the Greenland Ice Sheet. Though visual observation of large calving events is rare, ∼60 glacial earthquakes generated by these calving even...

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Published in: Journal of Geophysical Research: Earth Surface
ISSN: 2169-9003 2169-9011
Published: American Geophysical Union (AGU) 2021
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URI: https://cronfa.swan.ac.uk/Record/cronfa58790
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spelling 2022-10-26T14:55:33.1580380 v2 58790 2021-11-25 Improved Estimation of Glacial‐Earthquake Size Through New Modeling of the Seismic Source 8d6e71df690e725cd44191006dac31da 0000-0001-6714-6512 Tavi Murray Tavi Murray true false 8f68fdb1ba552a68be972ce17ba47a72 0000-0003-4082-7822 Timothy James Timothy James true false 2021-11-25 SGE The number of gigaton-sized iceberg-calving events occurring annually at Greenland glaciers is increasing, part of a larger trend of accelerating mass loss from the Greenland Ice Sheet. Though visual observation of large calving events is rare, ∼60 glacial earthquakes generated by these calving events are currently recorded each year by regional and global seismic stations. An empirical relationship between iceberg size and MCSF, a summary measure of glacial-earthquake size, was recently demonstrated by Olsen and Nettles (2019). However, MCSF is known to be sensitive to choices made in modeling the seismic source. We incorporate constraints on the seismic source from laboratory studies of calving and test multiple source time functions using synthetic and observed glacial-earthquake waveforms. We find that a simple, fixed time function with a shape informed by laboratory results greatly improves estimates of earthquake size. The average ratio of estimated to true peak force values is 1.03 for experiments using our preferred source model, compared with an average of 0.3 for models used in previous studies. We find that maximum-force values estimated from waveform modeling depend far less on model choices than does MCSF, and therefore prefer maximum force as a measure of glacial-earthquake size. Using both synthetic and real data, we confirm a correlation between maximum force and iceberg mass. Our results support the possibility of developing useful scaling relationships between seismic observables and physical parameters controlling glacier calving. Journal Article Journal of Geophysical Research: Earth Surface 126 12 American Geophysical Union (AGU) 2169-9003 2169-9011 Glacial Earthquake; Seismic Source; Greenland; Ice Seismicity; Iceberg; Calving 9 12 2021 2021-12-09 10.1029/2021jf006384 COLLEGE NANME Geography COLLEGE CODE SGE Swansea University 2022-10-26T14:55:33.1580380 2021-11-25T14:22:04.5965602 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Geography Kira G. Olsen 1 Meredith Nettles 2 L. Mac Cathles 3 Justin C. Burton 4 Tavi Murray 0000-0001-6714-6512 5 Timothy James 0000-0003-4082-7822 6 58790__21981__3d12f83a294c422eb57472d443d62e3d.pdf 58790.pdf 2021-12-31T16:41:00.7759388 Output 1299759 application/pdf Version of Record true 2022-05-24T00:00:00.0000000 © 2021. American Geophysical Union. All Rights Reserved. true eng
title Improved Estimation of Glacial‐Earthquake Size Through New Modeling of the Seismic Source
spellingShingle Improved Estimation of Glacial‐Earthquake Size Through New Modeling of the Seismic Source
Tavi Murray
Timothy James
title_short Improved Estimation of Glacial‐Earthquake Size Through New Modeling of the Seismic Source
title_full Improved Estimation of Glacial‐Earthquake Size Through New Modeling of the Seismic Source
title_fullStr Improved Estimation of Glacial‐Earthquake Size Through New Modeling of the Seismic Source
title_full_unstemmed Improved Estimation of Glacial‐Earthquake Size Through New Modeling of the Seismic Source
title_sort Improved Estimation of Glacial‐Earthquake Size Through New Modeling of the Seismic Source
author_id_str_mv 8d6e71df690e725cd44191006dac31da
8f68fdb1ba552a68be972ce17ba47a72
author_id_fullname_str_mv 8d6e71df690e725cd44191006dac31da_***_Tavi Murray
8f68fdb1ba552a68be972ce17ba47a72_***_Timothy James
author Tavi Murray
Timothy James
author2 Kira G. Olsen
Meredith Nettles
L. Mac Cathles
Justin C. Burton
Tavi Murray
Timothy James
format Journal article
container_title Journal of Geophysical Research: Earth Surface
container_volume 126
container_issue 12
publishDate 2021
institution Swansea University
issn 2169-9003
2169-9011
doi_str_mv 10.1029/2021jf006384
publisher American Geophysical Union (AGU)
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Biosciences, Geography and Physics - Geography{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Geography
document_store_str 1
active_str 0
description The number of gigaton-sized iceberg-calving events occurring annually at Greenland glaciers is increasing, part of a larger trend of accelerating mass loss from the Greenland Ice Sheet. Though visual observation of large calving events is rare, ∼60 glacial earthquakes generated by these calving events are currently recorded each year by regional and global seismic stations. An empirical relationship between iceberg size and MCSF, a summary measure of glacial-earthquake size, was recently demonstrated by Olsen and Nettles (2019). However, MCSF is known to be sensitive to choices made in modeling the seismic source. We incorporate constraints on the seismic source from laboratory studies of calving and test multiple source time functions using synthetic and observed glacial-earthquake waveforms. We find that a simple, fixed time function with a shape informed by laboratory results greatly improves estimates of earthquake size. The average ratio of estimated to true peak force values is 1.03 for experiments using our preferred source model, compared with an average of 0.3 for models used in previous studies. We find that maximum-force values estimated from waveform modeling depend far less on model choices than does MCSF, and therefore prefer maximum force as a measure of glacial-earthquake size. Using both synthetic and real data, we confirm a correlation between maximum force and iceberg mass. Our results support the possibility of developing useful scaling relationships between seismic observables and physical parameters controlling glacier calving.
published_date 2021-12-09T04:15:36Z
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score 11.035634

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