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Icelandic Volcano Erupts after Weeks of Unrest

eruption

Image credit: The new lava that came up in the eruption in the first hours of August 29. The photo was taken at 10:44am local time / Icelandic Coast Guard

For the past seven years, seismic activity has been observed to be increased gradually at Bárðarbunga, the second highest mountain in Iceland. According to the report by Nature, a recent swarm of small earthquakes signified that molten rock underground was moving, thus the area was blocked from the outside visitors. During their visit not long ago, when scientists flied over Vatnajökull, which is the largest ice cap in Europe and discovered that several depressions up to 15 meters deep in the side of the volcano. Known as cauldrons, they were the result of melt taking place at the base of the ice.

On August 29 this year, shortly after midnight local time, a fissure suddenly erupted near Bárðarbunga, which had sent gases and steam released from small lava fountains into the air just above the glacial ice north of the caldera in the volcano’s crown.

It was reported jointly by the University of Iceland and the Icelandic Met Office, responsible for monitoring volcanoes in Iceland that the eruption happened on the previous volcanic fissure on the Holuhraun lava field, which was nearly five kilometers north of the Dyngjujökull ice margin. The length of active fissure was around 600 meters.

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 Above is a 1973 satellite image of the Vatnajökull ice cap from NASA, with Bárðarbunga at its northwestern edge (top left).

From a webcam named as MilaSeismic located northeast of the site, the data and images collected demonstrated that the peak of eruption lasted for about 40 minutes and it came to the end four hours later. During such eruption, no volcanic ash was monitored, and no plume was identified by radar, thus the threat to aviation had been reduced to code orange ever since.

After several small earthquakes occurred, 0.4 cubic kilometers of magma generated a sheet of freshly cooled rock stretching for 45 kilometers north of Bárðarbunga. The dike so formed interacted with cracks going to the volcano called Askja 20 kilometers away. If the dike had succeeded in going all the way to Askja, the stress and supply of fresh magma could be the cause of its eruption.

 As British Geological Survey’s Evgenia IlyinskayaFurthermore said, from the total volume of magma involved, it was suggested that it was originated from the mantle of Earth. Possibly the source should be hundreds of kilometers below the surface of the crust rather than the shallow magma chamber beneath the volcano.

Check here for updates from the Icelandic Met Office.

Images: Icelandic Coast Guard (top) & NASA (middle) via Icelandic Met Office

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