Development of a subglacial lake monitored with radio-echo sounding: case study from the eastern Skaftá cauldron in the Vatnajökull ice cap, Iceland
We present repeated radio-echo sounding (RES, 5 MHz) on a profile grid over the eastern Skaftá cauldron (ESC) in Vatnajökull ice cap, Iceland. The ESC is a ∼ 3 km wide and 50–150 m deep ice cauldron created and maintained by subglacial geothermal activity of ∼ 1 GW. Beneath the cauldron and 200–400...
Published in: | The Cryosphere |
---|---|
Main Authors: | , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2021
|
Subjects: | |
Online Access: | https://doi.org/10.5194/tc-15-3731-2021 https://doaj.org/article/254228c7ef5649fdbc518e204c5ef1c0 |
id |
ftdoajarticles:oai:doaj.org/article:254228c7ef5649fdbc518e204c5ef1c0 |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:254228c7ef5649fdbc518e204c5ef1c0 2023-05-15T16:38:11+02:00 Development of a subglacial lake monitored with radio-echo sounding: case study from the eastern Skaftá cauldron in the Vatnajökull ice cap, Iceland E. Magnússon F. Pálsson M. T. Gudmundsson T. Högnadóttir C. Rossi T. Thorsteinsson B. G. Ófeigsson E. Sturkell T. Jóhannesson 2021-08-01T00:00:00Z https://doi.org/10.5194/tc-15-3731-2021 https://doaj.org/article/254228c7ef5649fdbc518e204c5ef1c0 EN eng Copernicus Publications https://tc.copernicus.org/articles/15/3731/2021/tc-15-3731-2021.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-15-3731-2021 1994-0416 1994-0424 https://doaj.org/article/254228c7ef5649fdbc518e204c5ef1c0 The Cryosphere, Vol 15, Pp 3731-3749 (2021) Environmental sciences GE1-350 Geology QE1-996.5 article 2021 ftdoajarticles https://doi.org/10.5194/tc-15-3731-2021 2022-12-31T12:40:17Z We present repeated radio-echo sounding (RES, 5 MHz) on a profile grid over the eastern Skaftá cauldron (ESC) in Vatnajökull ice cap, Iceland. The ESC is a ∼ 3 km wide and 50–150 m deep ice cauldron created and maintained by subglacial geothermal activity of ∼ 1 GW. Beneath the cauldron and 200–400 m thick ice, water accumulates in a subglacial lake and is released semi-regularly in jökulhlaups . The RES record consists of annual surveys conducted at the beginning of every summer during the period 2014–2020. Comparison of the RES surveys reveals variable lake area (0.5–4.1 km 2 ) and enables traced reflections from the lake roof to be distinguished from bedrock reflections. This allows construction of a digital elevation model (DEM) of the bedrock in the area, further constrained by two borehole measurements at the cauldron centre. It also allows creation of lake thickness maps and an estimate of lake volume at the time of each survey, which we compare with lowering patterns and released water volumes obtained from pre- and post-jökulhlaup surface DEMs. The estimated lake volume was 250 GL (gigalitres = 10 6 m 3 ) in June 2015, but 320 ± 20 GL drained from the ESC in October 2015. In June 2018, RES profiles revealed a lake volume of 185 GL, while 220 ± 30 GL were released in a jökulhlaup in August 2018. Considering the water accumulation over the periods between RES surveys and jökulhlaups, this indicates 10 %–20 % uncertainty in the RES-derived volumes at times when significant jökulhlaups may be expected. Article in Journal/Newspaper Ice cap Iceland The Cryosphere Vatnajökull Directory of Open Access Journals: DOAJ Articles Skaftá ENVELOPE(-17.933,-17.933,63.783,63.783) The Cauldron ENVELOPE(99.394,99.394,-66.648,-66.648) Vatnajökull ENVELOPE(-16.823,-16.823,64.420,64.420) The Cryosphere 15 8 3731 3749 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 E. Magnússon F. Pálsson M. T. Gudmundsson T. Högnadóttir C. Rossi T. Thorsteinsson B. G. Ófeigsson E. Sturkell T. Jóhannesson Development of a subglacial lake monitored with radio-echo sounding: case study from the eastern Skaftá cauldron in the Vatnajökull ice cap, Iceland |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
We present repeated radio-echo sounding (RES, 5 MHz) on a profile grid over the eastern Skaftá cauldron (ESC) in Vatnajökull ice cap, Iceland. The ESC is a ∼ 3 km wide and 50–150 m deep ice cauldron created and maintained by subglacial geothermal activity of ∼ 1 GW. Beneath the cauldron and 200–400 m thick ice, water accumulates in a subglacial lake and is released semi-regularly in jökulhlaups . The RES record consists of annual surveys conducted at the beginning of every summer during the period 2014–2020. Comparison of the RES surveys reveals variable lake area (0.5–4.1 km 2 ) and enables traced reflections from the lake roof to be distinguished from bedrock reflections. This allows construction of a digital elevation model (DEM) of the bedrock in the area, further constrained by two borehole measurements at the cauldron centre. It also allows creation of lake thickness maps and an estimate of lake volume at the time of each survey, which we compare with lowering patterns and released water volumes obtained from pre- and post-jökulhlaup surface DEMs. The estimated lake volume was 250 GL (gigalitres = 10 6 m 3 ) in June 2015, but 320 ± 20 GL drained from the ESC in October 2015. In June 2018, RES profiles revealed a lake volume of 185 GL, while 220 ± 30 GL were released in a jökulhlaup in August 2018. Considering the water accumulation over the periods between RES surveys and jökulhlaups, this indicates 10 %–20 % uncertainty in the RES-derived volumes at times when significant jökulhlaups may be expected. |
format |
Article in Journal/Newspaper |
author |
E. Magnússon F. Pálsson M. T. Gudmundsson T. Högnadóttir C. Rossi T. Thorsteinsson B. G. Ófeigsson E. Sturkell T. Jóhannesson |
author_facet |
E. Magnússon F. Pálsson M. T. Gudmundsson T. Högnadóttir C. Rossi T. Thorsteinsson B. G. Ófeigsson E. Sturkell T. Jóhannesson |
author_sort |
E. Magnússon |
title |
Development of a subglacial lake monitored with radio-echo sounding: case study from the eastern Skaftá cauldron in the Vatnajökull ice cap, Iceland |
title_short |
Development of a subglacial lake monitored with radio-echo sounding: case study from the eastern Skaftá cauldron in the Vatnajökull ice cap, Iceland |
title_full |
Development of a subglacial lake monitored with radio-echo sounding: case study from the eastern Skaftá cauldron in the Vatnajökull ice cap, Iceland |
title_fullStr |
Development of a subglacial lake monitored with radio-echo sounding: case study from the eastern Skaftá cauldron in the Vatnajökull ice cap, Iceland |
title_full_unstemmed |
Development of a subglacial lake monitored with radio-echo sounding: case study from the eastern Skaftá cauldron in the Vatnajökull ice cap, Iceland |
title_sort |
development of a subglacial lake monitored with radio-echo sounding: case study from the eastern skaftá cauldron in the vatnajökull ice cap, iceland |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-15-3731-2021 https://doaj.org/article/254228c7ef5649fdbc518e204c5ef1c0 |
long_lat |
ENVELOPE(-17.933,-17.933,63.783,63.783) ENVELOPE(99.394,99.394,-66.648,-66.648) ENVELOPE(-16.823,-16.823,64.420,64.420) |
geographic |
Skaftá The Cauldron Vatnajökull |
geographic_facet |
Skaftá The Cauldron Vatnajökull |
genre |
Ice cap Iceland The Cryosphere Vatnajökull |
genre_facet |
Ice cap Iceland The Cryosphere Vatnajökull |
op_source |
The Cryosphere, Vol 15, Pp 3731-3749 (2021) |
op_relation |
https://tc.copernicus.org/articles/15/3731/2021/tc-15-3731-2021.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-15-3731-2021 1994-0416 1994-0424 https://doaj.org/article/254228c7ef5649fdbc518e204c5ef1c0 |
op_doi |
https://doi.org/10.5194/tc-15-3731-2021 |
container_title |
The Cryosphere |
container_volume |
15 |
container_issue |
8 |
container_start_page |
3731 |
op_container_end_page |
3749 |
_version_ |
1766028476443262976 |