Intense seismicity during the 2014–15 Bárðarbunga-Holuhraun rifting event, Iceland, reveals the nature of dike-induced earthquakes and caldera collapse mechanisms
Over two weeks in August 2014 magma propagated 48km laterally from Bárðarbunga volcano before erupting at Holuhraun for 6 months, accompanied by collapse of the caldera. A dense seismic network recorded over 47,000 earthquakes before, during and after the rifting event. More than 30,000 earthquakes...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/294700 2024-01-14T10:08:02+01:00 Intense seismicity during the 2014–15 Bárðarbunga-Holuhraun rifting event, Iceland, reveals the nature of dike-induced earthquakes and caldera collapse mechanisms White, Robert Agustsdottir, Thorbjorg Winder, Tom Woods, Jennifer Greenfield, Tim Brandsdottir, Bryndis 2019-10-08 application/pdf https://www.repository.cam.ac.uk/handle/1810/294700 https://doi.org/10.17863/CAM.41805 eng eng Wiley-Blackwell http://dx.doi.org/10.1029/2018jb016010 Journal of Geophysical Research https://www.repository.cam.ac.uk/handle/1810/294700 doi:10.17863/CAM.41805 All rights reserved Baroarbunga caldera collapse rifting event Holuhraun earthquake source mechanisms dike Article 2019 ftunivcam https://doi.org/10.17863/CAM.41805 2023-12-21T23:23:34Z Over two weeks in August 2014 magma propagated 48km laterally from Bárðarbunga volcano before erupting at Holuhraun for 6 months, accompanied by collapse of the caldera. A dense seismic network recorded over 47,000 earthquakes before, during and after the rifting event. More than 30,000 earthquakes delineate the segmented dike intrusion. Earthquake source mechanisms show exclusively strike-slip faulting, occurring near the base of the dike along pre-existing weaknesses aligned with the rift fabric, while the dike widened largely aseismically. The slip-sense of faulting is controlled by the orientation of the dike relative to the local rift fabric, demonstrated by an abrupt change from right- to left-lateral faulting as the dike turns to propagate from an easterly to a northerly direction. Approximately 4,000 earthquakes associated with the caldera collapse delineate an inner caldera fault zone, with good correlation to geodetic observations. Caldera subsidence was largely aseismic, with seismicity accounting for 10% or less of the geodetic moment. Approximately 90% of the seismic moment release occurred on the northern rim, suggesting an asymmetric collapse. Well-constrained focal mechanisms reveal sub-vertical arrays of normal faults, with fault planes dipping inward at 60 9 , along both the north and south caldera margins. These steep normal faults strike sub-parallel to the caldera rims, with slip vectors pointing towards the center of subsidence. The maximum depth of seismicity defines the base of the seismogenic crust under Bárðarbunga as 6km b.s.l., in broad agreement with constraints from geodesy and geobarometry for the minimum depth to the melt storage region. Article in Journal/Newspaper Iceland Apollo - University of Cambridge Repository Holuhraun ENVELOPE(-16.831,-16.831,64.852,64.852) |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
Baroarbunga caldera collapse rifting event Holuhraun earthquake source mechanisms dike |
spellingShingle |
Baroarbunga caldera collapse rifting event Holuhraun earthquake source mechanisms dike White, Robert Agustsdottir, Thorbjorg Winder, Tom Woods, Jennifer Greenfield, Tim Brandsdottir, Bryndis Intense seismicity during the 2014–15 Bárðarbunga-Holuhraun rifting event, Iceland, reveals the nature of dike-induced earthquakes and caldera collapse mechanisms |
topic_facet |
Baroarbunga caldera collapse rifting event Holuhraun earthquake source mechanisms dike |
description |
Over two weeks in August 2014 magma propagated 48km laterally from Bárðarbunga volcano before erupting at Holuhraun for 6 months, accompanied by collapse of the caldera. A dense seismic network recorded over 47,000 earthquakes before, during and after the rifting event. More than 30,000 earthquakes delineate the segmented dike intrusion. Earthquake source mechanisms show exclusively strike-slip faulting, occurring near the base of the dike along pre-existing weaknesses aligned with the rift fabric, while the dike widened largely aseismically. The slip-sense of faulting is controlled by the orientation of the dike relative to the local rift fabric, demonstrated by an abrupt change from right- to left-lateral faulting as the dike turns to propagate from an easterly to a northerly direction. Approximately 4,000 earthquakes associated with the caldera collapse delineate an inner caldera fault zone, with good correlation to geodetic observations. Caldera subsidence was largely aseismic, with seismicity accounting for 10% or less of the geodetic moment. Approximately 90% of the seismic moment release occurred on the northern rim, suggesting an asymmetric collapse. Well-constrained focal mechanisms reveal sub-vertical arrays of normal faults, with fault planes dipping inward at 60 9 , along both the north and south caldera margins. These steep normal faults strike sub-parallel to the caldera rims, with slip vectors pointing towards the center of subsidence. The maximum depth of seismicity defines the base of the seismogenic crust under Bárðarbunga as 6km b.s.l., in broad agreement with constraints from geodesy and geobarometry for the minimum depth to the melt storage region. |
format |
Article in Journal/Newspaper |
author |
White, Robert Agustsdottir, Thorbjorg Winder, Tom Woods, Jennifer Greenfield, Tim Brandsdottir, Bryndis |
author_facet |
White, Robert Agustsdottir, Thorbjorg Winder, Tom Woods, Jennifer Greenfield, Tim Brandsdottir, Bryndis |
author_sort |
White, Robert |
title |
Intense seismicity during the 2014–15 Bárðarbunga-Holuhraun rifting event, Iceland, reveals the nature of dike-induced earthquakes and caldera collapse mechanisms |
title_short |
Intense seismicity during the 2014–15 Bárðarbunga-Holuhraun rifting event, Iceland, reveals the nature of dike-induced earthquakes and caldera collapse mechanisms |
title_full |
Intense seismicity during the 2014–15 Bárðarbunga-Holuhraun rifting event, Iceland, reveals the nature of dike-induced earthquakes and caldera collapse mechanisms |
title_fullStr |
Intense seismicity during the 2014–15 Bárðarbunga-Holuhraun rifting event, Iceland, reveals the nature of dike-induced earthquakes and caldera collapse mechanisms |
title_full_unstemmed |
Intense seismicity during the 2014–15 Bárðarbunga-Holuhraun rifting event, Iceland, reveals the nature of dike-induced earthquakes and caldera collapse mechanisms |
title_sort |
intense seismicity during the 2014–15 bárðarbunga-holuhraun rifting event, iceland, reveals the nature of dike-induced earthquakes and caldera collapse mechanisms |
publisher |
Wiley-Blackwell |
publishDate |
2019 |
url |
https://www.repository.cam.ac.uk/handle/1810/294700 https://doi.org/10.17863/CAM.41805 |
long_lat |
ENVELOPE(-16.831,-16.831,64.852,64.852) |
geographic |
Holuhraun |
geographic_facet |
Holuhraun |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/294700 doi:10.17863/CAM.41805 |
op_rights |
All rights reserved |
op_doi |
https://doi.org/10.17863/CAM.41805 |
_version_ |
1788062464512884736 |