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...
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ftunivbruxelles:oai:dipot.ulb.ac.be:2013/270528 2023-05-15T16:21:46+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 T.S. Ágústsdóttir, Thorbjörg 2018-05 1 full-text file(s): application/pdf http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/270528 https://dipot.ulb.ac.be/dspace/bitstream/2013/270528/4/doi_254155.pdf en eng uri/info:doi/10.1016/j.epsl.2018.03.020 uri/info:pii/S0012821X18301420 uri/info:scp/85044524763 https://dipot.ulb.ac.be/dspace/bitstream/2013/270528/4/doi_254155.pdf http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/270528 1 full-text file(s): info:eu-repo/semantics/openAccess Earth and planetary science letters, 490 Sciences de la terre et du cosmos Géochimie Pétrologie Géographie physique Sciences de l'espace Bárðarbunga-Holuhraun dyke intrusion Iceland long-period seismicity tremor volcano seismology info:eu-repo/semantics/article info:ulb-repo/semantics/articlePeerReview info:ulb-repo/semantics/openurl/article 2018 ftunivbruxelles 2022-06-12T21:44:47Z 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. SCOPUS: ar.j info:eu-repo/semantics/published Article in Journal/Newspaper glacier Ice cap Iceland DI-fusion : dépôt institutionnel de l'Université libre de Bruxelles (ULB) Dyngjujökull ENVELOPE(-17.007,-17.007,64.717,64.717) Holuhraun ENVELOPE(-16.831,-16.831,64.852,64.852) |
institution |
Open Polar |
collection |
DI-fusion : dépôt institutionnel de l'Université libre de Bruxelles (ULB) |
op_collection_id |
ftunivbruxelles |
language |
English |
topic |
Sciences de la terre et du cosmos Géochimie Pétrologie Géographie physique Sciences de l'espace Bárðarbunga-Holuhraun dyke intrusion Iceland long-period seismicity tremor volcano seismology |
spellingShingle |
Sciences de la terre et du cosmos Géochimie Pétrologie Géographie physique Sciences de l'espace Bárðarbunga-Holuhraun dyke intrusion Iceland long-period seismicity tremor volcano seismology Woods, Jennifer Donaldson, Clare White, Robert S. Caudron, Corentin Brandsdóttir, Bryndís Hudson, Thomas T.S. Ágústsdóttir, Thorbjörg Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014–15 Bárðarbunga rifting event, Iceland |
topic_facet |
Sciences de la terre et du cosmos Géochimie Pétrologie Géographie physique Sciences de l'espace Bárðarbunga-Holuhraun dyke intrusion Iceland long-period seismicity tremor volcano seismology |
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. SCOPUS: ar.j info:eu-repo/semantics/published |
format |
Article in Journal/Newspaper |
author |
Woods, Jennifer Donaldson, Clare White, Robert S. Caudron, Corentin Brandsdóttir, Bryndís Hudson, Thomas T.S. Ágústsdóttir, Thorbjörg |
author_facet |
Woods, Jennifer Donaldson, Clare White, Robert S. Caudron, Corentin Brandsdóttir, Bryndís Hudson, Thomas T.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 |
publishDate |
2018 |
url |
http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/270528 https://dipot.ulb.ac.be/dspace/bitstream/2013/270528/4/doi_254155.pdf |
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_source |
Earth and planetary science letters, 490 |
op_relation |
uri/info:doi/10.1016/j.epsl.2018.03.020 uri/info:pii/S0012821X18301420 uri/info:scp/85044524763 https://dipot.ulb.ac.be/dspace/bitstream/2013/270528/4/doi_254155.pdf http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/270528 |
op_rights |
1 full-text file(s): info:eu-repo/semantics/openAccess |
_version_ |
1766009751626317824 |