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Grímsvötn eruption and the importance of research

26 May

This perspective on the Grímsvötn eruption and volcanic activity, ash transport and ash detection comes from Dr Mike Burton. Dr Burton is a Senior Researcher at the Istituto Nazionale di Geofisica e Vulcanologia, Pisa, Italy. His research includes utilising novel gas and video imaging techniques to better understand volcanic processes. At the EGU General Assembly 2011, he convened GMPV5 Monitoring and observations of active volcanoes using in-situ and remote sensing techniques along with Thomas Staudacher , Jurgen Neuberg , Hugo Delgado Granados, and Alessandro Bonaccorso.”

Once more with feeling

Just a little more than a year after the eruption of Eyjafalla another Icelandic volcano, Grímsvötn, is injecting volcanic ash and gas high into the atmosphere, disrupting air traffic over Europe. This time the eruption has been much more intense, with an eruption column reaching up to 20 km in the initial stages of the activity. Fortunately the eruption has swiftly waned, and at the time of writing eruptive activity has reduced greatly. Nevertheless, the volcanic ash already injected into the upper troposphere will continue to circulate for several days before it becomes so dilute that it no longer poses a risk to aviation, and we see that airports in northern Europe have had to close as air traffic restrictions are put in place. Such events remind us of the enormous importance that European level research in volcanic activity, ash transport and ash detection has for improving our ability to both understand and react to rapidly changing events.

Volcanic eruptions, while challenging to predict, are produced from well-known areas, particularly in Iceland where frequent eruptions have been extremely well-documented and well-observed for many years. This allows statistical analysis of the frequency of such events and preparation for their eventuality. Unfortunately, while scientists from many nations have lobbied for increased resources to deal with this issue, governments have been slow to act, but the recent eruptions on Iceland and their consequent impact on the European economy through disruption to air traffic has produced an unprecedented focus on this issue. This focus was exemplified at the recent EGU General Assembly in Vienna in April where a series of well-attended sessions focussed on the science of the 2010 eruption, modelling of the ash dispersal and analysis of satellite and lidar measurements of ash. It is clear that further research is a fundamental priority for Europe in order to produce improving responses to the inevitable eruptions which will occur in the future, not just from Iceland, but also from Italy and potentially the Azores and Canary Islands as well.

Grimsvötn eruption observations from the field

26 May

This description on the Grímsvötn eruption comes from Dr Olgeir Sigmarsson, an Icelandic volcanologist who is Director of Research, CNRS at the Laboratoire Magmas et Volcans, Observatoire de Physique du Globe de Clermont-Ferrand. He also works at the Institute of Earth Sciences, University of Iceland. His research is on geochemistry: genesis, chronology and evolution of magma. Dr Sigmarsson has been collecting tephra samples from the glacier in the field near to the Grimsvötn volcano and the below contains information from his Icelandic colleagues.

The Grimsvötn eruption 2011 has stopped for the time being. It started around 19:00 last Saturday (21 May) and it’s eruption column rose to approximately 17 km during the first night. It thus penetrated into the stratosphere, observed for the first time for an eruption from Grimsvötn volcano. Grimsvötn is a complex caldera structure covered by the largest ice-cap in Europe, namely Vatnajökull. The high-temperature area melts the floating ice on the subglacial lake that occasionally is lifted from the bedrock by the water mass, emptying the lake and creating glacier bursts, better known as jökulhlaup. Such pressure release generates more vigorous boiling in the geothermal system and sometimes may act as a trigger for an eruption (such as in the 2004 eruption). Fortunately the last jökulhlaup occurred last autumn, leaving little water in the subglacial caldera lake.

The actual eruption emitted approximately 10-20 tons/sec of tephra during the first day but declined rapidly and on the 24th May the column rose only to 3 km height during occasional explosions. On the 4th day, only vapour explosions with little solid material were observed at the crater close to the south wall of the caldera. Tephra fall was noticed all over Iceland (with the exception of the Westfjord peninsula) with grain-size having approximately 10% finer than 10 micronmeters and 50% finer than 50 micronmeters. Based on preliminary measured tephra thickness, the volume is crudely estimated as ½ cubic km of freshly fallen tephra.

Seismicity and deformation indicate a shallow magma source and the magma is basaltic of quartz-normatve tholeiite composition similar to all historic tephra. However, since the Laki eruption, increased concentrations of incompatible elements have increased with time suggesting a closed-system behaviour with minimal deeper input of more primitive magma. The fact the actual eruption was very explosive in the beginning and rose above the tropopause indicate either (1) a more evolved basaltic magma than before or (2) a deeper gas-rich magma entering into the plumbing system beneath Grimsvötn caldera. The first possibility would suggest that the volcano is evolving towards more evolved magma with higher gas content
and potential high explosivity, whereas the second possibility suggests a changing feeding system with renewal of fresh basalt from depth. These two possibilities can be distinguished by precise trace element analysis of the actual tephra.

Grímsvötn volcanic eruption

24 May

The Grímsvötn volcano in Iceland started erupting on 21 May 2011. Icelandic airspace was closed soon after with flights now being affected in the United Kingdom.

This post brings together some good sources of imagery and information. These sources are not endorsed by the European Geosciences Union, more a resource letting people know what is available. If you know of a good source of information, let us know in the comments or email us.

The UK Met Office is responsible for ash cloud monitoring for Northern European airspace. Their pages include warnings issues and maps showing predicted ash cloud movements.

NASA Earth Observatoryimagery is available (such as below). Including commentary on the image.

Grímsvötn Modis Natural-Color Image (NASA, 2011)

The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) has imagery and animcationsfrom various satellites, including real-time images. An example is shown below.

Grímsvötn Altitude Imagery, copyright EUMETSAT (2011)

Grímsvötn Altitude Imagery, copyright EUMETSAT (2011)

News and information from Iceland itself is available from the Iceland Met Office and the University of Iceland Institute of Earth Sciences which has an Eruption in Grímsvötn 2011 page, which contains photos, satellite imagery, GPS time series, chemical composition information, and relevant scientific publications alongside status reports.

Relevant abstracts about the Grímsvötn volcano that were presented at the EGU General Assembly 2011 are Óladóttir et al., Thordarson et al., and Magnússon et al..