Scenes from a devil’s kitchen
The current phase of activity at the Icelandic volcano Bárðarbunga continues: Since the end of August lava has been intermittently spurting from a surface fissure. Members of the LMU IsViews Project were on the scene within hours to document the event and monitor developments.
Red-hot lava gushes onto the frozen surface and thick clouds of steam and sulfur dioxide ascend into the skies over Iceland. This hellish scene on Bárðarbunga can be seen in all its fiery splendor in an aerial photograph taken as part of the LMU project IsViews. The snapshot was obtained only 5 hours after the first signs of surface activity at the Icelandic volcano, and was taken from a specially equipped aircraft contracted to collect high-resolution imagery of Bárðarbunga by IsViews and its Icelandic partner Fjarkönnun ehf. “We were waiting for such a localized vent eruption to occur at Bárðarbunga,” says Dr. Ulrich Münzer of the Geology Section of the Department of Earth and Environmental Sciences at LMU. “The recent rise in the level of seismic activity in the region suggested that an eruption was in the offing.” Münzer has been monitoring subglacial volcanoes in Iceland for over 25 years. The goal of the LMU project IsViews is to develop an early warning system for Iceland based on high-resolution aerial photography and satellite data which is able to alert local authorities and emergency services of pending natural disasters such as volcanic eruptions, glacier destabilization and landslides.
The effusive eruption began on the 29. August several kilometers northeast of Bárðarbunga, when lava was first observed on the surface. Since then molten lava has been intermittingly spurting from a surface fissure which now extends for several kilometers in Holuhraun. The lava front is now more than 20 km wide and the lava field covers an area of nearly 40 km2. The eruption has been accompanied by the release of huge amounts of sulfur dioxide. It remains to be seen whether the activity will also extend to Bárðarbunga’s central caldera. In the vicinity of the volcano seismic activity has increased significantly. Since the onset of the eruption, swarms of earthquakes with magnitudes of up to 5.7 have been recorded in the area at the northwest end of Vatnajökull, the largest glacier on Iceland. Münzer and his colleagues believe that a powerful eruption at Bárðarbunga is not unlikely. “In particular, the seismic activity indicates that we haven’t seen the end of the present eruptive phase as yet,” says Dr. Julia Jaenicke, a member of the IsViews team. The eruption of Eyjafjallajökull in 2010 was also preceded by a period of increased seismic activity, but as Jaenicke emphasizes, predicting the precise timing of a full-scale eruption is always difficult.
Waiting for the big one
GPS measurements taken by Icelandic researchers on the plateau formed by the approximately 1-km-thick ice-sheet that conceals Bárðarbunga’s central caldera has subsided by more than 20 meters. “The reasons for this remain unclear,” says Münzer. On the one hand, the subsidence could be a “passive” response to the ongoing extrusion of massive amounts of lava, which may have led to a reduction in the pressure in the magma chamber. The partial collapse of the overlying plateau could, however, also be related to a subglacial melting process. That in turn would imply that magma is still being forced upwards and that the pressure within the volcano is actually building up. “If that is the case, then at some stage the cork will pop, and we will get an explosive eruption,” Münzer predicts. With this possibility in mind, incoming high-resolution radar data gathered by the German satellite TerraSAR-X and optical ranging data from the RapidEye satellite will be carefully scrutinized for indications that subsurface ice is melting.
For the major threat posed by the onset of activity at Bárðarbunga lies in the interaction of fire and ice which is such a feature of volcanic activity on Iceland: “If large volumes of acidic magma come into contact with meltwater, one can expect a so-called phreatomagmatic eruption, an abrupt and massive explosion that emits a plume which is enriched in ash particles, similar to what we saw at Eyjafjallajökull,” says Münzer. The consequences of that scenario would be catastrophic: Such an eruption at Bárðarbunga could lead to the melting of enormous volumes of ice and produce what is known as a glacial outburst flood. When the Katla volcano erupted in 1918, a glacial flood discharged meltwater at rates of up to 300,000 cubic meters per second and inundated the periglacial Icelandic foreland. Likewise, in the event of an eruption at Bárðarbunga, the head of the IsViews project expects even more extensive flooding to occur, which could affect the entire drainage system of the Jökulsá á Fjöllum and the sparsely populated Northern section of Iceland, including such tourist attractions as the Dettifoss waterfall and the Àsbyrgi canyon.
If the present period of enhanced activity should culminate in a full-scale eruption of Bárðarbunga, it could once more lead to the disruption of air traffic by volcanic activity. Only four years ago, the ash that injected into the atmosphere during the Eyjafjallajökull eruption caused the closure of European airspace for many days. Recent studies carried out by volcanologists led by Professor Donald Dingwell, Director of the Department of Earth and Environmental Sciences at LMU, have quantified the threat that volcanic ash presents to aircraft engines. Their experiments showed that high-temperature volcanic ash adheres to moving parts of the engine, forming a coating that seriously affects the workings of the turbines. “To detect the first signs of such an explosive eruption, we will continue to monitor developments on the basis of our satellite data,” Münzer says.
Dr. Ulrich Münzer heads the project IsViews (Iceland subglacial Volcanoes interdisciplinary early warning system), a collaborative venture between LMU, the German Center for Aeronautics and Space Research (Remote Sensing Technology Institute), the Bavarian Academy of Sciences (Commission for Geodetics und Glaciology) and Remote Sensing Solutions GmbH. IsViews is financially supported by the Bavarian Ministry of Economics and Media, Energy and Technology.