Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle
We report the results of the highest-resolution teleseismic tomography study yet performed of the upper mantle beneath Iceland. The experiment used data gathered by the Iceland Hotspot Project, which operated a 35-station network of continuously recording, digital, broad-band seismometers over all o...
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Oxford University Press
2001
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fthighwire:oai:open-archive.highwire.org:gji:146/2/504 2023-05-15T16:44:23+02:00 Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle Foulger, G. R. Pritchard, M. J. Julian, B. R. Evans, J. R. Allen, R. M. Nolet, G. Morgan, W. J. Bergsson, B. H. Erlendsson, P. Jakobsdottir, S. Ragnarsson, S. Stefansson, R. Vogfjörd, K. 2001-08-01 00:00:00.0 text/html http://gji.oxfordjournals.org/cgi/content/short/146/2/504 https://doi.org/10.1046/j.0956-540x.2001.01470.x en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/146/2/504 http://dx.doi.org/10.1046/j.0956-540x.2001.01470.x Copyright (C) 2001, Oxford University Press Articles TEXT 2001 fthighwire https://doi.org/10.1046/j.0956-540x.2001.01470.x 2013-05-27T12:32:55Z We report the results of the highest-resolution teleseismic tomography study yet performed of the upper mantle beneath Iceland. The experiment used data gathered by the Iceland Hotspot Project, which operated a 35-station network of continuously recording, digital, broad-band seismometers over all of Iceland 1996–1998. The structure of the upper mantle was determined using the ACH damped least-squares method and involved 42 stations, 3159 P -wave, and 1338 S -wave arrival times, including the phases P , pP , sP , PP , SP , PcP , PKIKP , pPKIKP , S , sS , SS , SKS and Sdiff . Artefacts, both perceptual and parametric, were minimized by well-tested smoothing techniques involving layer thinning and offset-and-averaging. Resolution is good beneath most of Iceland from ∼60 km depth to a maximum of ∼450 km depth and beneath the Tjornes Fracture Zone and near-shore parts of the Reykjanes ridge. The results reveal a coherent, negative wave-speed anomaly with a diameter of 200–250 km and anomalies in P -wave speed, V P , as strong as −2.7 per cent and in S -wave speed, V S , as strong as −4.9 per cent. The anomaly extends from the surface to the limit of good resolution at ∼450 km depth. In the upper ∼250 km it is centred beneath the eastern part of the Middle Volcanic Zone, coincident with the centre of the ∼100 mGal Bouguer gravity low over Iceland, and a lower crustal low-velocity zone identified by receiver functions. This is probably the true centre of the Iceland hotspot. In the upper ∼200 km, the low-wave-speed body extends along the Reykjanes ridge but is sharply truncated beneath the Tjornes Fracture Zone. This suggests that material may flow unimpeded along the Reykjanes ridge from beneath Iceland but is blocked beneath the Tjornes Fracture Zone. The magnitudes of the V P , V S and V P / V S anomalies cannot be explained by elevated temperature alone, but favour a model of maximum temperature anomalies < 200 K, along with up to ∼2 per cent of partial melt in the depth range ∼100–300 km beneath east-central ... Text Iceland HighWire Press (Stanford University) Reykjanes ENVELOPE(-22.250,-22.250,65.467,65.467) Geophysical Journal International 146 2 504 530 |
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HighWire Press (Stanford University) |
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fthighwire |
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English |
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Articles Foulger, G. R. Pritchard, M. J. Julian, B. R. Evans, J. R. Allen, R. M. Nolet, G. Morgan, W. J. Bergsson, B. H. Erlendsson, P. Jakobsdottir, S. Ragnarsson, S. Stefansson, R. Vogfjörd, K. Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle |
topic_facet |
Articles |
description |
We report the results of the highest-resolution teleseismic tomography study yet performed of the upper mantle beneath Iceland. The experiment used data gathered by the Iceland Hotspot Project, which operated a 35-station network of continuously recording, digital, broad-band seismometers over all of Iceland 1996–1998. The structure of the upper mantle was determined using the ACH damped least-squares method and involved 42 stations, 3159 P -wave, and 1338 S -wave arrival times, including the phases P , pP , sP , PP , SP , PcP , PKIKP , pPKIKP , S , sS , SS , SKS and Sdiff . Artefacts, both perceptual and parametric, were minimized by well-tested smoothing techniques involving layer thinning and offset-and-averaging. Resolution is good beneath most of Iceland from ∼60 km depth to a maximum of ∼450 km depth and beneath the Tjornes Fracture Zone and near-shore parts of the Reykjanes ridge. The results reveal a coherent, negative wave-speed anomaly with a diameter of 200–250 km and anomalies in P -wave speed, V P , as strong as −2.7 per cent and in S -wave speed, V S , as strong as −4.9 per cent. The anomaly extends from the surface to the limit of good resolution at ∼450 km depth. In the upper ∼250 km it is centred beneath the eastern part of the Middle Volcanic Zone, coincident with the centre of the ∼100 mGal Bouguer gravity low over Iceland, and a lower crustal low-velocity zone identified by receiver functions. This is probably the true centre of the Iceland hotspot. In the upper ∼200 km, the low-wave-speed body extends along the Reykjanes ridge but is sharply truncated beneath the Tjornes Fracture Zone. This suggests that material may flow unimpeded along the Reykjanes ridge from beneath Iceland but is blocked beneath the Tjornes Fracture Zone. The magnitudes of the V P , V S and V P / V S anomalies cannot be explained by elevated temperature alone, but favour a model of maximum temperature anomalies < 200 K, along with up to ∼2 per cent of partial melt in the depth range ∼100–300 km beneath east-central ... |
format |
Text |
author |
Foulger, G. R. Pritchard, M. J. Julian, B. R. Evans, J. R. Allen, R. M. Nolet, G. Morgan, W. J. Bergsson, B. H. Erlendsson, P. Jakobsdottir, S. Ragnarsson, S. Stefansson, R. Vogfjörd, K. |
author_facet |
Foulger, G. R. Pritchard, M. J. Julian, B. R. Evans, J. R. Allen, R. M. Nolet, G. Morgan, W. J. Bergsson, B. H. Erlendsson, P. Jakobsdottir, S. Ragnarsson, S. Stefansson, R. Vogfjörd, K. |
author_sort |
Foulger, G. R. |
title |
Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle |
title_short |
Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle |
title_full |
Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle |
title_fullStr |
Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle |
title_full_unstemmed |
Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle |
title_sort |
seismic tomography shows that upwelling beneath iceland is confined to the upper mantle |
publisher |
Oxford University Press |
publishDate |
2001 |
url |
http://gji.oxfordjournals.org/cgi/content/short/146/2/504 https://doi.org/10.1046/j.0956-540x.2001.01470.x |
long_lat |
ENVELOPE(-22.250,-22.250,65.467,65.467) |
geographic |
Reykjanes |
geographic_facet |
Reykjanes |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/146/2/504 http://dx.doi.org/10.1046/j.0956-540x.2001.01470.x |
op_rights |
Copyright (C) 2001, Oxford University Press |
op_doi |
https://doi.org/10.1046/j.0956-540x.2001.01470.x |
container_title |
Geophysical Journal International |
container_volume |
146 |
container_issue |
2 |
container_start_page |
504 |
op_container_end_page |
530 |
_version_ |
1766034672488284160 |