University of Leicester contributes to the monitoring of Bárðabunga

Posted by ap507 at Sep 03, 2014 10:40 AM |
Research team involved in collaborative study
University of Leicester contributes to the monitoring of Bárðabunga

A SEIS-UK seismometer station deployed on Vatnajökull ice cap directly above the underground molten rock (Photo: Tobba Ágústsdóttir)

The University of Leicester hosts SEIS-UK, the Natural Environment Research Council’s onshore seismic facility, which has loaned in excess of 50 seismometers Professor Bob White at the University of Cambridge. 

Together with instruments owned by the Cambridge seismology group Professor White has been able to install a huge array of over 70 instruments in Iceland. This array has been monitoring the Bárðabunga area since 2006, with SEIS-UK providing equipment, training, logistical and field support, technical expertise and data processing capabilities to Professor White’s group.

The volume of magma on the move under and beyond Bárðabunga is enormous. At 350 million cubic metres it is twice the size of the Eyjfjallajökull eruption of 2010 – and that stopped over 100,000 flights. In the last 24 hours an extra 50 million cubic metres of magma have been injected into the system. Molten rock is moving northwards, and has now covered a distance of some 40km; at a depth of 5-10km below the Earth’s surface (Figure 1).

Figure 1
Figure 1: Grey dots show seismicity 2006-2013. Coloured dots show seismic events during the first 10 days of the magmatic intrusion. Note the steady northward progression of the underground dyke containing molten rock as it moves NE from the source beneath Bárðabunga volcano. Red and orange triangles show the location SEIS-UK seismometers on loan to the University of Cambridge (diagram by Tim Greenfield, University of Cambridge).
If the magma continues northwards, it could connect with the Askja volcano, and may liberate a lot of magma that resides there (as mapped and published by the Cambridge group following previous SEIS-UK loans). When Askja erupted in 1875 it was a massive eruption which led to the depopulation of northeast Iceland as ash-fall destroyed the subsistence farming.

At the time of writing, the Cambridge team have driven into the restricted area around Askja to deploy further SEIS-UK instruments above the tip of the propagating magma (known as a dyke), as well as servicing the already-deployed instruments and downloading new data. Whether or not it erupts, these data are likely to yield considerable new insights into how molten rock moves underground. Due to their proximity to the activity, the aviation and civil hazard warnings issued in Iceland also depend heavily on these instruments.

Prof Páll Einarsson, geophysicist at the University of Iceland, commented: "It is already clear that the event presently in progress is a significant magmatic and tectonic event. In terms of seismicity, volumes, and displacements involved only two events in recent decades are comparable to this one. These are the Gjálp eruption in the Bárðarbunga area in 1996 and the Krafla rifting episode of 1975-1989. The presently propagating dike is superseded by only the initial dyke in the Krafla sequence of dykes. In fact, is resembles that event in many ways. The possibility must be seriously considered that we are witnessing the initial phase of a major rifting episode on the scale of the Krafla episode and the similar episode that began in Afar in 2005."

SEIS-UK is based in the Department of Geology at the University of Leicester. The group consists of seismologists Dr Victoria Lane and Dr David Hawthorn, director Professor Richard England and Computing Officer Dr Andrew Myers. More information can be found here.

Since the article went to press there have been active eruptions in the area; click here to see video footage from the Cambridge seismology group.

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