Diurnal seismicity cycle linked to subsurface melting on an ice shelf
Seismograms acquired on the McMurdo Ice Shelf, Antarctica, during an Austral summer melt season (November 2016–January 2017) reveal a diurnal cycle of seismicity, consisting of hundreds of thousands of small ice quakes limited to a 6–12 hour period during the evening, in an area where there is subst...
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ftdoajarticles:oai:doaj.org/article:031b29c1de6a467382f06c3f1c24c4f9 2023-05-15T13:29:29+02:00 Diurnal seismicity cycle linked to subsurface melting on an ice shelf Douglas R. MacAyeal Alison F. Banwell Emile A. Okal Jinqiao Lin Ian C. Willis Becky Goodsell Grant J. MacDonald 2019-09-01T00:00:00Z https://doi.org/10.1017/aog.2018.29 https://doaj.org/article/031b29c1de6a467382f06c3f1c24c4f9 EN eng Cambridge University Press https://www.cambridge.org/core/product/identifier/S0260305518000290/type/journal_article https://doaj.org/toc/0260-3055 https://doaj.org/toc/1727-5644 doi:10.1017/aog.2018.29 0260-3055 1727-5644 https://doaj.org/article/031b29c1de6a467382f06c3f1c24c4f9 Annals of Glaciology, Vol 60, Pp 137-157 (2019) Antarctic glaciology debris-covered glaciers ice shelves ice temperature seismics Meteorology. Climatology QC851-999 article 2019 ftdoajarticles https://doi.org/10.1017/aog.2018.29 2023-03-12T01:31:55Z Seismograms acquired on the McMurdo Ice Shelf, Antarctica, during an Austral summer melt season (November 2016–January 2017) reveal a diurnal cycle of seismicity, consisting of hundreds of thousands of small ice quakes limited to a 6–12 hour period during the evening, in an area where there is substantial subsurface melting. This cycle is explained by thermally induced bending and fracture of a frozen surface superimposed on a subsurface slush/water layer that is supported by solar radiation penetration and absorption. A simple, one-dimensional model of heat transfer driven by observed surface air temperature and shortwave absorption reproduces the presence and absence (as daily weather dictated) of the observed diurnal seismicity cycle. Seismic event statistics comparing event occurrence with amplitude suggest that the events are generated in a fractured medium featuring relatively low stresses, as is consistent with a frozen surface superimposed on subsurface slush. Waveforms of the icequakes are consistent with hydroacoustic phases at frequency $ {\bf \gt} \bf 75\,{\bf Hz}$ and flexural-gravity waves at frequency $ \bf {\bf \lt}25\,{\bf Hz}$. Our results suggest that seismic observation may prove useful in monitoring subsurface melting in a manner that complements other ground-based methods as well as remote sensing. Article in Journal/Newspaper Annals of Glaciology Antarc* Antarctic Antarctica Ice Shelf Ice Shelves McMurdo Ice Shelf Directory of Open Access Journals: DOAJ Articles Antarctic Austral McMurdo Ice Shelf ENVELOPE(166.500,166.500,-78.000,-78.000) Annals of Glaciology 60 79 137 157 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Antarctic glaciology debris-covered glaciers ice shelves ice temperature seismics Meteorology. Climatology QC851-999 |
spellingShingle |
Antarctic glaciology debris-covered glaciers ice shelves ice temperature seismics Meteorology. Climatology QC851-999 Douglas R. MacAyeal Alison F. Banwell Emile A. Okal Jinqiao Lin Ian C. Willis Becky Goodsell Grant J. MacDonald Diurnal seismicity cycle linked to subsurface melting on an ice shelf |
topic_facet |
Antarctic glaciology debris-covered glaciers ice shelves ice temperature seismics Meteorology. Climatology QC851-999 |
description |
Seismograms acquired on the McMurdo Ice Shelf, Antarctica, during an Austral summer melt season (November 2016–January 2017) reveal a diurnal cycle of seismicity, consisting of hundreds of thousands of small ice quakes limited to a 6–12 hour period during the evening, in an area where there is substantial subsurface melting. This cycle is explained by thermally induced bending and fracture of a frozen surface superimposed on a subsurface slush/water layer that is supported by solar radiation penetration and absorption. A simple, one-dimensional model of heat transfer driven by observed surface air temperature and shortwave absorption reproduces the presence and absence (as daily weather dictated) of the observed diurnal seismicity cycle. Seismic event statistics comparing event occurrence with amplitude suggest that the events are generated in a fractured medium featuring relatively low stresses, as is consistent with a frozen surface superimposed on subsurface slush. Waveforms of the icequakes are consistent with hydroacoustic phases at frequency $ {\bf \gt} \bf 75\,{\bf Hz}$ and flexural-gravity waves at frequency $ \bf {\bf \lt}25\,{\bf Hz}$. Our results suggest that seismic observation may prove useful in monitoring subsurface melting in a manner that complements other ground-based methods as well as remote sensing. |
format |
Article in Journal/Newspaper |
author |
Douglas R. MacAyeal Alison F. Banwell Emile A. Okal Jinqiao Lin Ian C. Willis Becky Goodsell Grant J. MacDonald |
author_facet |
Douglas R. MacAyeal Alison F. Banwell Emile A. Okal Jinqiao Lin Ian C. Willis Becky Goodsell Grant J. MacDonald |
author_sort |
Douglas R. MacAyeal |
title |
Diurnal seismicity cycle linked to subsurface melting on an ice shelf |
title_short |
Diurnal seismicity cycle linked to subsurface melting on an ice shelf |
title_full |
Diurnal seismicity cycle linked to subsurface melting on an ice shelf |
title_fullStr |
Diurnal seismicity cycle linked to subsurface melting on an ice shelf |
title_full_unstemmed |
Diurnal seismicity cycle linked to subsurface melting on an ice shelf |
title_sort |
diurnal seismicity cycle linked to subsurface melting on an ice shelf |
publisher |
Cambridge University Press |
publishDate |
2019 |
url |
https://doi.org/10.1017/aog.2018.29 https://doaj.org/article/031b29c1de6a467382f06c3f1c24c4f9 |
long_lat |
ENVELOPE(166.500,166.500,-78.000,-78.000) |
geographic |
Antarctic Austral McMurdo Ice Shelf |
geographic_facet |
Antarctic Austral McMurdo Ice Shelf |
genre |
Annals of Glaciology Antarc* Antarctic Antarctica Ice Shelf Ice Shelves McMurdo Ice Shelf |
genre_facet |
Annals of Glaciology Antarc* Antarctic Antarctica Ice Shelf Ice Shelves McMurdo Ice Shelf |
op_source |
Annals of Glaciology, Vol 60, Pp 137-157 (2019) |
op_relation |
https://www.cambridge.org/core/product/identifier/S0260305518000290/type/journal_article https://doaj.org/toc/0260-3055 https://doaj.org/toc/1727-5644 doi:10.1017/aog.2018.29 0260-3055 1727-5644 https://doaj.org/article/031b29c1de6a467382f06c3f1c24c4f9 |
op_doi |
https://doi.org/10.1017/aog.2018.29 |
container_title |
Annals of Glaciology |
container_volume |
60 |
container_issue |
79 |
container_start_page |
137 |
op_container_end_page |
157 |
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1766000920961744896 |