Gravity and elevation changes at Askja, Iceland
Ground tilt measurements demonstrate that Askja is in a state of unrest, and that in the period 1988 - 1991 a maximum 48 +/- 3 µrad tilt occurred down towards the centre of the caldera. This is consistent with 126 mm of deflation at the centre of the caldera with a 2.5 - 3.0 km depth to the source o...
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Language: | English |
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1993
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ftopenunivgb:oai:oro.open.ac.uk:66 2024-06-23T07:54:01+00:00 Gravity and elevation changes at Askja, Iceland Rymer, Hazel Tryggvason, Eysteinn 1993-07 application/pdf https://oro.open.ac.uk/66/ https://oro.open.ac.uk/66/1/Rymer_5_-_Askja_short_paper.pdf en eng https://oro.open.ac.uk/66/1/Rymer_5_-_Askja_short_paper.pdf Rymer, Hazel <https://oro.open.ac.uk/view/person/hr4.html> and Tryggvason, Eysteinn (1993). Gravity and elevation changes at Askja, Iceland. Bulletin of Volcanology, 55(5) pp. 362–371. Journal Item PeerReviewed 1993 ftopenunivgb 2024-05-29T00:44:15Z Ground tilt measurements demonstrate that Askja is in a state of unrest, and that in the period 1988 - 1991 a maximum 48 +/- 3 µrad tilt occurred down towards the centre of the caldera. This is consistent with 126 mm of deflation at the centre of the caldera with a 2.5 - 3.0 km depth to the source of deformation. The volume of the subsidence bowl is 6.2 x 106 m3. When combined with high precision microgravity measurements, the overall change in sub-surface mass may be quantified. After correction for the observed elevation change using the free air gradient of gravity measured for each station, the total change in mass is estimated to be less than 109 kg. A small residual ground inflation and net gravity increase in the eastern part of the caldera may be caused by dyke intrusion in this region. The minimum dimensions of such an intrusion or complex of intrusions are 1m width, up to 100m deep and up to several hundred metres thick. Article in Journal/Newspaper Iceland The Open University: Open Research Online (ORO) Askja ENVELOPE(-16.802,-16.802,65.042,65.042) Bulletin of Volcanology 55 5 362 371 |
institution |
Open Polar |
collection |
The Open University: Open Research Online (ORO) |
op_collection_id |
ftopenunivgb |
language |
English |
description |
Ground tilt measurements demonstrate that Askja is in a state of unrest, and that in the period 1988 - 1991 a maximum 48 +/- 3 µrad tilt occurred down towards the centre of the caldera. This is consistent with 126 mm of deflation at the centre of the caldera with a 2.5 - 3.0 km depth to the source of deformation. The volume of the subsidence bowl is 6.2 x 106 m3. When combined with high precision microgravity measurements, the overall change in sub-surface mass may be quantified. After correction for the observed elevation change using the free air gradient of gravity measured for each station, the total change in mass is estimated to be less than 109 kg. A small residual ground inflation and net gravity increase in the eastern part of the caldera may be caused by dyke intrusion in this region. The minimum dimensions of such an intrusion or complex of intrusions are 1m width, up to 100m deep and up to several hundred metres thick. |
format |
Article in Journal/Newspaper |
author |
Rymer, Hazel Tryggvason, Eysteinn |
spellingShingle |
Rymer, Hazel Tryggvason, Eysteinn Gravity and elevation changes at Askja, Iceland |
author_facet |
Rymer, Hazel Tryggvason, Eysteinn |
author_sort |
Rymer, Hazel |
title |
Gravity and elevation changes at Askja, Iceland |
title_short |
Gravity and elevation changes at Askja, Iceland |
title_full |
Gravity and elevation changes at Askja, Iceland |
title_fullStr |
Gravity and elevation changes at Askja, Iceland |
title_full_unstemmed |
Gravity and elevation changes at Askja, Iceland |
title_sort |
gravity and elevation changes at askja, iceland |
publishDate |
1993 |
url |
https://oro.open.ac.uk/66/ https://oro.open.ac.uk/66/1/Rymer_5_-_Askja_short_paper.pdf |
long_lat |
ENVELOPE(-16.802,-16.802,65.042,65.042) |
geographic |
Askja |
geographic_facet |
Askja |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
https://oro.open.ac.uk/66/1/Rymer_5_-_Askja_short_paper.pdf Rymer, Hazel <https://oro.open.ac.uk/view/person/hr4.html> and Tryggvason, Eysteinn (1993). Gravity and elevation changes at Askja, Iceland. Bulletin of Volcanology, 55(5) pp. 362–371. |
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Bulletin of Volcanology |
container_volume |
55 |
container_issue |
5 |
container_start_page |
362 |
op_container_end_page |
371 |
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1802645953724809216 |