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Intrusion could trigger eruption in Askja

27.08.2014 - 20:15
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Should the magma intrusion from Bardarbunga, advance as far as the Askja Caldera, it may propagate into the shallow magma chamber of Askja and trigger an eruption, says Agust Gudmundsson, professor of geophysics at Royal Holloway University. Most intrusions do however not lead to eruptions.

„As things presently stand, the odds are that the magma-driven fracture (a dike intrusion) may propagate into the Askja magma chamber,“ says Dr. Gudmundsson. "If the dike intrusion enters the magma chamber of Askja, it is very likely that this event would rupture that chamber and possibly trigger an eruption of Askja."

Gudmundson notes that the intrusion has reached a lenght of 42 - 43 kilometers. He estimates that the total volume of magma that has entered the dike intrusion is 1 - 2 cubic kilometers. "But it has to be said that most magma intrusions anywhere, within or outside of volcanoes, do not reach the surface; they stop on their way to the surface. So most potential eruptions are just in the pipelines, so to speak; they never happen."

Magnus Tumi Gudmunsson, professor of geophysics at the University of Iceland´s Institute of Earth Sciences says the intrusion is now about 10 kilometers south of the Askja volcanic system, quite near a fissure that was formed about a century ago. That fissure lies southwards from Thorvaldsfjall, one of the mountains that forms a ring around Askja.

The dike intrusion, which comes from the Bardarbunga Volcanic System shows no sign of stopping its propagation to the north.

"What we are observing here is an exceptional event", says Agust Gudmundsson. "This is the first time that we observe a dike intrusion from one volcanic system propagating into another volcanic system, namely the Askja Volcanic System. We have had evidence of this possibility from older volcanic systems in Iceland, and we have provided models as to how and why it could happen. But this is absolutely the first time we really observe such an event happening – namely, a large volume of magma flowing for more than 40 km from one volcanic system into another one."