Monitoring Magmatism and Intrusion from the Bardabunga Volcano, Iceland

Lead Research Organisation: University of Cambridge
Department Name: Earth Sciences

Abstract

An eruption in Iceland has presented a unique opportunity to monitor the lateral movement and eventual eruption of melt using a network of seismometers deployed directly above and around the volcanic system. An intense earthquake swarm began on 2014 August 16 at Bardarbunga central volcano in Central Iceland under the Vatnajokull ice cap, which has continued to be very active. It then produced a dyke which travelled northwards over 45 km towards the Askja volcanic system at aproximate depths of 6-12 km and produced a small fissure eruption near its tip on 2014 August 29. GPS measurements show continued movement of the rift and suggest that about 400 million cubic metres of magma has already been injected into the dyke and that melt continues to flow into it. So continued activity is likely, probably for many months.

This is a significant magmatic and tectonic event. In terms of seismicity, volumes of melt and displacements involved only two events in Iceland during recent decades are comparable to this one. These are the Gjálp eruption in the Bárdarbunga area in 1996 and the Krafla rifting episode of 1975-1989. The presently propagating dyke is equalled only by the initial dyke in the Krafla sequence of dykes. Possibly we are witnessing the intial phase of a major rifting episode on the scale of the Krafla volvcanism and the similar episode that began in Afar in 2005.

The Cambridge research group is uniquely well placed to monitor this tectono-magmatic event. We already have a wide array of 50 broad-band seismometers operating around Vatnajokull and the Askja volcanic system and had 15 SEIS-UK seismometers sitting in Reykjavik. For good depth control and constraint on the cracking and failures causing microseismicity it is important to have seismic sensors directly above the activity. Unusually and importantly we are in a superb position to monitor simultaneously both the source of the melt in the Bardabunga volcano and its transit and emergence along the later dyke flowing northwards along the rift system.

We don't know how this magmatic-rifting event will develop, but it is likely to continue for many months because there is so much molten rock sitting at a shallow crustal level. We will run 15 extra seismometers through the next 12 months to obtain a continuous record throughout the entire tectono-magmatic episode.

Planned Impact

This eruption is already attracting huge publicity for the scientific work, with the media flocking to us for interviews and photos. At the time of writing (29 September), just 12 hours after the eruption started, I have had requests from three separate film companies, including the BBC and the Discovery Channel in Canada to come out and film our seismic fieldwork for both news and longer documentary items. We are welcoming all these and they will provide enormous outreach opportunities both for our work and for NERC if they come to fruition. Meantime we are doing interviews for the BBC, including the Today program, BBC Scotland and Look East.

Immediately the seismic activity increased a week ago we contacted media connections at NERC, Cambridge University and the BBC and there has been a good BBC website continually updated (at the time of writing this is at http://www.bbc.co.uk/news/world-europe-28977773), using photos and daily reports from our PhD students in the field. One of the Cambridge PhD students is achieving a large Twitter following (@fencingTobba) with her real-time reports.

We are also contributing considerably to the hazard warning system in Iceland, since the six closest seismometers are all installed by Cambridge and telemetered to the Icelandic Meteorological Office where they are being used by them for the continually updated seismicity maps. The understanding gained from monitoring this dyke movement and eruption will materially improve future hazard warnings both in Iceland and also elsewhere in volcanic systems globally. We are partners in the EU FutureVolc consortium which is developing improved volcanic monitoring and warning systems using Iceland as a Supersite and our results will contribute to that and provide a good mechanism for dissemination.

Publications

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Green R (2017) Ambient noise tomography reveals upper crustal structure of Icelandic rifts in Earth and Planetary Science Letters

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Greenfield T (2015) Building icelandic igneous crust by repeated melt injections MICROSEISMICITY FROM DEEP MELT TRANSPORT in Journal of Geophysical Research: Solid Earth

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Greenfield T (2018) Seismicity of the Askja and Bárðarbunga volcanic systems of Iceland, 2009-2015 in Journal of Volcanology and Geothermal Research

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White RS (2019) Melt movement through the Icelandic crust. in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences

 
Description We have discovered that when a volcano becomes unstable and is ready to erupt, the molten rock may flow laterally tens of kilometres underground before breaching the surface and erupting.
Exploitation Route This has helped understanding of volcanic hazard assessment. In this case although the volcano lay under an icecap it did not erupt straight up, which would have caused massive ash volumes to be injected into the upper atmosphere. In 2010 the eruption of Eyjafjallajokull grounded 100,000 flights in Europe for this reason. Instead the melt 46 km underground before erupting just beyond the edge of the glacier, where it formed an effusive eruption with little ash generation.
Sectors Energy,Transport

URL http://www.cam.ac.uk/research/discussion/luck-and-lava
 
Description As a result of this work, we have been chosen as one of only 21 exhibitors at the prestigious Royal Society Summer Exhibition in July 2016. This attracts 15,000 people, from school groups and the public through to researchers, FRS, government ministers, Royalty and senior academics.
First Year Of Impact 2016
Sector Education
Impact Types Societal