Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 Bárðarbunga rifting event, Iceland
The 2014–15 Bárðarbunga–Holuhraun rifting event comprised the best-monitored dyke intrusion to date and the largest eruption in Iceland in 230 years. A huge variety of seismicity was produced, including over 30,000 volcano-tectonic earthquakes (VTs) associated with the dyke propagation at ∼6 km dept...
id |
ftucambridgeesc:oai:eprints.esc.cam.ac.uk:4091 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
University of Cambridge, Department of Earth Sciences: ESC Publications |
op_collection_id |
ftucambridgeesc |
language |
English |
topic |
02 - Geodynamics Geophysics and Tectonics |
spellingShingle |
02 - Geodynamics Geophysics and Tectonics Woods, Jennifer Donaldson, Clare White, Robert S. Caudron, Corentin Brandsdóttir, Bryndís Hudson, Thomas S. Ágústsdóttir, Thorbjörg Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 Bárðarbunga rifting event, Iceland |
topic_facet |
02 - Geodynamics Geophysics and Tectonics |
description |
The 2014–15 Bárðarbunga–Holuhraun rifting event comprised the best-monitored dyke intrusion to date and the largest eruption in Iceland in 230 years. A huge variety of seismicity was produced, including over 30,000 volcano-tectonic earthquakes (VTs) associated with the dyke propagation at ∼6 km depth below sea level, and large-magnitude earthquakes accompanying the collapse of Bárðarbunga caldera. We here study the long-period seismicity associated with the rifting event. We systematically detect and locate both long-period events (LPs) and tremor during the dyke propagation phase and the first week of the eruption. We identify clusters of highly similar, repetitive LPs, which have a peak frequency of ∼1 Hz and clear P and S phases followed by a long-duration coda. The source mechanisms are remarkably consistent between clusters and also fundamentally different to those of the VTs. We accurately locate LP clusters near each of three ice cauldrons (depressions formed by basal melting) that were observed on the surface of Dyngjujökull glacier above the path of the dyke. Most events are in the vicinity of the northernmost cauldron, at shallower depth than the VTs associated with lateral dyke propagation. At the two northerly cauldrons, periods of shallow seismic tremor following the clusters of LPs are also observed. Given that the LPs occur at ∼4 km depth and in swarms during times of dyke-stalling, we infer that they result from excitation of magmatic fluid-filled cavities and indicate magma ascent. We suggest that the tremor is the climax of the vertical melt movement, arising from either rapid, repeated excitation of the same LP cavities, or sub-glacial eruption processes. This long-period seismicity therefore represents magma pathways between the depth of the dyke-VT earthquakes and the surface. Notably, we do not detect tremor associated with each cauldron, despite melt reaching the base of the overlying ice cap, a concern for hazard monitoring. |
format |
Article in Journal/Newspaper |
author |
Woods, Jennifer Donaldson, Clare White, Robert S. Caudron, Corentin Brandsdóttir, Bryndís Hudson, Thomas S. Ágústsdóttir, Thorbjörg |
author_facet |
Woods, Jennifer Donaldson, Clare White, Robert S. Caudron, Corentin Brandsdóttir, Bryndís Hudson, Thomas S. Ágústsdóttir, Thorbjörg |
author_sort |
Woods, Jennifer |
title |
Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 Bárðarbunga rifting event, Iceland |
title_short |
Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 Bárðarbunga rifting event, Iceland |
title_full |
Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 Bárðarbunga rifting event, Iceland |
title_fullStr |
Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 Bárðarbunga rifting event, Iceland |
title_full_unstemmed |
Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 Bárðarbunga rifting event, Iceland |
title_sort |
long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 bárðarbunga rifting event, iceland |
publisher |
Elsevier |
publishDate |
2017 |
url |
http://eprints.esc.cam.ac.uk/4091/ http://eprints.esc.cam.ac.uk/4091/1/S0012821X18301420_via%3Dihub http://eprints.esc.cam.ac.uk/4091/2/1-s2.0-S0012821X18301420-mmc1.pdf http://eprints.esc.cam.ac.uk/4091/3/1-s2.0-S0012821X18301420-mmc2.txt http://eprints.esc.cam.ac.uk/4091/4/1-s2.0-S0012821X18301420-mmc3.txt http://eprints.esc.cam.ac.uk/4091/5/1-s2.0-S0012821X18301420-mmc4.txt http://eprints.esc.cam.ac.uk/4091/6/1-s2.0-S0012821X18301420-mmc5.mp4 http://eprints.esc.cam.ac.uk/4091/7/1-s2.0-S0012821X18301420-mmc6.mp4 https://www.sciencedirect.com/science/article/pii/S0012821X18301420?via%3Dihub#se0210 https://doi.org/10.1016/j.epsl.2018.03.020 |
long_lat |
ENVELOPE(-17.007,-17.007,64.717,64.717) ENVELOPE(-16.831,-16.831,64.852,64.852) |
geographic |
Dyngjujökull Holuhraun |
geographic_facet |
Dyngjujökull Holuhraun |
genre |
glacier Ice cap Iceland |
genre_facet |
glacier Ice cap Iceland |
op_relation |
http://eprints.esc.cam.ac.uk/4091/1/S0012821X18301420_via%3Dihub http://eprints.esc.cam.ac.uk/4091/2/1-s2.0-S0012821X18301420-mmc1.pdf http://eprints.esc.cam.ac.uk/4091/3/1-s2.0-S0012821X18301420-mmc2.txt http://eprints.esc.cam.ac.uk/4091/4/1-s2.0-S0012821X18301420-mmc3.txt http://eprints.esc.cam.ac.uk/4091/5/1-s2.0-S0012821X18301420-mmc4.txt http://eprints.esc.cam.ac.uk/4091/6/1-s2.0-S0012821X18301420-mmc5.mp4 http://eprints.esc.cam.ac.uk/4091/7/1-s2.0-S0012821X18301420-mmc6.mp4 Woods, Jennifer and Donaldson, Clare and White, Robert S. and Caudron, Corentin and Brandsdóttir, Bryndís and Hudson, Thomas S. and Ágústsdóttir, Thorbjörg (2017) Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 Bárðarbunga rifting event, Iceland. Earth and Planetary Science Letters, 490. ISSN 0012-821X DOI https://doi.org/10.1016/j.epsl.2018.03.020 <https://doi.org/10.1016/j.epsl.2018.03.020> |
op_rights |
cc_by cc_by_nc |
op_rightsnorm |
CC-BY CC-BY-NC |
op_doi |
https://doi.org/10.1016/j.epsl.2018.03.020 |
container_title |
Earth and Planetary Science Letters |
container_volume |
490 |
container_start_page |
216 |
op_container_end_page |
229 |
_version_ |
1766009766654509056 |
spelling |
ftucambridgeesc:oai:eprints.esc.cam.ac.uk:4091 2023-05-15T16:21:47+02:00 Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 Bárðarbunga rifting event, Iceland Woods, Jennifer Donaldson, Clare White, Robert S. Caudron, Corentin Brandsdóttir, Bryndís Hudson, Thomas S. Ágústsdóttir, Thorbjörg 2017-02-05 text video http://eprints.esc.cam.ac.uk/4091/ http://eprints.esc.cam.ac.uk/4091/1/S0012821X18301420_via%3Dihub http://eprints.esc.cam.ac.uk/4091/2/1-s2.0-S0012821X18301420-mmc1.pdf http://eprints.esc.cam.ac.uk/4091/3/1-s2.0-S0012821X18301420-mmc2.txt http://eprints.esc.cam.ac.uk/4091/4/1-s2.0-S0012821X18301420-mmc3.txt http://eprints.esc.cam.ac.uk/4091/5/1-s2.0-S0012821X18301420-mmc4.txt http://eprints.esc.cam.ac.uk/4091/6/1-s2.0-S0012821X18301420-mmc5.mp4 http://eprints.esc.cam.ac.uk/4091/7/1-s2.0-S0012821X18301420-mmc6.mp4 https://www.sciencedirect.com/science/article/pii/S0012821X18301420?via%3Dihub#se0210 https://doi.org/10.1016/j.epsl.2018.03.020 en eng Elsevier http://eprints.esc.cam.ac.uk/4091/1/S0012821X18301420_via%3Dihub http://eprints.esc.cam.ac.uk/4091/2/1-s2.0-S0012821X18301420-mmc1.pdf http://eprints.esc.cam.ac.uk/4091/3/1-s2.0-S0012821X18301420-mmc2.txt http://eprints.esc.cam.ac.uk/4091/4/1-s2.0-S0012821X18301420-mmc3.txt http://eprints.esc.cam.ac.uk/4091/5/1-s2.0-S0012821X18301420-mmc4.txt http://eprints.esc.cam.ac.uk/4091/6/1-s2.0-S0012821X18301420-mmc5.mp4 http://eprints.esc.cam.ac.uk/4091/7/1-s2.0-S0012821X18301420-mmc6.mp4 Woods, Jennifer and Donaldson, Clare and White, Robert S. and Caudron, Corentin and Brandsdóttir, Bryndís and Hudson, Thomas S. and Ágústsdóttir, Thorbjörg (2017) Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 Bárðarbunga rifting event, Iceland. Earth and Planetary Science Letters, 490. ISSN 0012-821X DOI https://doi.org/10.1016/j.epsl.2018.03.020 <https://doi.org/10.1016/j.epsl.2018.03.020> cc_by cc_by_nc CC-BY CC-BY-NC 02 - Geodynamics Geophysics and Tectonics Article PeerReviewed 2017 ftucambridgeesc https://doi.org/10.1016/j.epsl.2018.03.020 2020-08-27T18:09:55Z The 2014–15 Bárðarbunga–Holuhraun rifting event comprised the best-monitored dyke intrusion to date and the largest eruption in Iceland in 230 years. A huge variety of seismicity was produced, including over 30,000 volcano-tectonic earthquakes (VTs) associated with the dyke propagation at ∼6 km depth below sea level, and large-magnitude earthquakes accompanying the collapse of Bárðarbunga caldera. We here study the long-period seismicity associated with the rifting event. We systematically detect and locate both long-period events (LPs) and tremor during the dyke propagation phase and the first week of the eruption. We identify clusters of highly similar, repetitive LPs, which have a peak frequency of ∼1 Hz and clear P and S phases followed by a long-duration coda. The source mechanisms are remarkably consistent between clusters and also fundamentally different to those of the VTs. We accurately locate LP clusters near each of three ice cauldrons (depressions formed by basal melting) that were observed on the surface of Dyngjujökull glacier above the path of the dyke. Most events are in the vicinity of the northernmost cauldron, at shallower depth than the VTs associated with lateral dyke propagation. At the two northerly cauldrons, periods of shallow seismic tremor following the clusters of LPs are also observed. Given that the LPs occur at ∼4 km depth and in swarms during times of dyke-stalling, we infer that they result from excitation of magmatic fluid-filled cavities and indicate magma ascent. We suggest that the tremor is the climax of the vertical melt movement, arising from either rapid, repeated excitation of the same LP cavities, or sub-glacial eruption processes. This long-period seismicity therefore represents magma pathways between the depth of the dyke-VT earthquakes and the surface. Notably, we do not detect tremor associated with each cauldron, despite melt reaching the base of the overlying ice cap, a concern for hazard monitoring. Article in Journal/Newspaper glacier Ice cap Iceland University of Cambridge, Department of Earth Sciences: ESC Publications Dyngjujökull ENVELOPE(-17.007,-17.007,64.717,64.717) Holuhraun ENVELOPE(-16.831,-16.831,64.852,64.852) Earth and Planetary Science Letters 490 216 229 |