Iceland volcanic eruption mystery

January 2015 – SKAFTAFELL, Iceland – Just north of here, on the far side of the impenetrable Vatnajokull ice sheet, lava is spewing from a crack in the earth on the flanks of Bardarbunga, one of Iceland’s largest volcanoes. By volcanologists’ standards, it is a peaceful eruption, the lava merely spreading across the landscape as gases bubble out of it.

For now, those gases – especially sulfur dioxide, which can cause respiratory and other problems – are the main concern, prompting health advisories in the capital, Reykjavik, 150 miles to the west, and elsewhere around the country. But sometime soon, the top of Bardarbunga, which lies under as much as half a mile of ice, may erupt explosively. That could send plumes of gritty ash into the sky that could shut down air travel across Europe because of the damage the ash can do to jet engines. And it could unleash a torrent of glacial meltwater that could wipe out the only road connecting southern Iceland to the capital. All of that could happen. Then again, it may not.

Such are the mysteries of volcanoes that more than four months after Bardarbunga began erupting, scientists here are still debating what will happen next. The truth is, no one really knows. Volcanic eruptions are among the Earth’s most cataclysmic events, and understanding how and when they happen can be crucial to saving lives and reducing damage to infrastructure and other property. Scientists have several powerful tools to help, but in the end, they are often reduced to analyzing possibilities within possibilities, chains of potential events that could unfold in multiple ways.

said Pall Einarsson, a geophysicist at the University of Iceland. “They can suddenly decide to do something very different.” For now, the eruption remains what volcanologists call an effusive one – the lava, consisting primarily of molten basalt, is thin enough that the gases bubble out with little explosive force.

And the amounts of sulfur dioxide and other gases, while a concern locally, are nowhere near the amounts produced by an eruption at a fissure called Laki in the 1780s. In that event, the gases poisoned livestock across Iceland, leading to a famine that killed about a quarter of the country’s population and had other effects in Europe and elsewhere. One possibility is that the current eruption will eventually peter out as the source of magma is depleted…

– Shortened –