Icelandic volcanic system rumbling and growing more unpredictable

September 2014 – ICELAND - The red-hot fountains of molten lava, glowing like wildfire, are nothing short of spectacular. Yet they could be ominous portents of things to come. For the second time in four nail-biting years, seismologists in the land of fire and ice, Iceland, are bracing for a monumental volcanic eruption that, once again, threatens to disrupt European air traffic. Back in 2010, the Eyjafjallajokull volcano, which melted through 200 meters of glacier, sent more than 200 million cubic meters of fine ash billowing almost 10 kilometers into the sky. As a result, several European countries were forced to ground or re-route thousands of flights for several days. This time the threat of an eruption – potentially even more powerful than the one in 2010 – is posed by Bardarbunga, the biggest of Iceland’s 30 or so volcanic systems. Located roughly at the country’s centre, the volcano’s 10-kilometre caldera lies several hundred meters beneath Vatnajokull, Europe’s largest glacier by volume. Scientists are taking the latest rumblings seriously: roughly 8000 years ago, after all, the volcanic leviathan let rip with the largest eruption of the past 10,000 years.

“It is very difficult to predict exactly what will happen with an eruption,” says Monash University vulcanologist Professor Ray Cas, who is president of the International Association for Volcanology and Chemistry of the Earth. “Some just fizzle out after relatively minor activity, while others develop into major eruptions,” Cas says. To gauge the likelihood and extent of an eruption, scientists gather all manner of information, including earthquake patterns, ground movements and the complex chemistry of gases. “In this case, the eruption could just stop, or if the molten magma migrates under the glacial ice cap, a sub-glacial eruption could begin – with the potential to become very explosive,” he says. “This is because of the super-heating melt-water at the base of the glacier.”

Radiating from Bardarbunga’s crater is a fracture in the crust that trends towards the north-east, says another Monash earth scientist, Dr Patrick Hayman. Initially, he says, magma moved from a depth of up to 15 kilometres below the crater, to the tip of this fracture – then pushed and shoved its way further north-eastwards. “Many of the earthquakes recorded in recent weeks have been related to this movement of magma,” Hayman notes. “The first eruption, last month, occurred about 5 kilometers north-east of the glacier’s edge, forming what is known as a fissure eruption – a long, narrow crack from which magma erupts.” Because of the connection between the fracture and the volcano, the concern has been that magma will rise beneath the glacier between the fissure and the volcanic crater. “So there is a real possibility of a showdown between the magma and ice,” Hayman warns. –Brisbane Times

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