Holuhraun Continues To Erupt

It’s been almost a month since the Holuhraun eruption started, and there doesn’t seem to be any indication of it stopping soon. Meanwhile, the Bárðarbunga caldera continues to subside, which means that it must still be feeding magma to the Holuhraun eruptive fissure. The surrounding area is still closed to the public (sorry!) due to high concentrations of poison gas and the continuing risk of flooding.

In the last two weeks there has been quite a bit of air pollution (mostly sulphur dioxide, the one that smells like rotten eggs) due to gas emanating from the eruptive fissure. Daily forecasts on which areas of the country should expect pollution can be found on the Icelandic Meteorological Office’s web page www.vedur.is, and those areas are advised to close their windows and turn up the heat. However, no serious cases of people being affected by this pollution have been reported so far.

By now Holuhraun has created an impressive 37 square kilometre lava field that’s half a cubic kilometre in volume—six times more than Eyjafjallajökull spewed in 2010 (not including ash!). The most recent eruption that comes closest to Holuhraun in volume of lava is the 1947 Hekla eruption, whose lava field reached 0.8 cubic kilometres in volume. That Hekla eruption, however, lasted for a total of thirteen months, so the eruptive rate of lava is much higher in Holuhraun.

Now, this is starting to sound like a lot of lava, but it doesn’t come close to the catastrophic eruption of Laki in 1783, which produced an incredible lava field with a volume of fourteen cubic kilometres. The Laki eruption lasted for eight months and it’s safe to say that it changed history in a big way. Not only did it lead to the death of more than half of Iceland’s livestock from fluoride poisoning—which in turn caused a famine that killed off a quarter of the nation’s population—but it also affected the entire northern hemisphere. Laki significantly changed weather patterns for years to come, especially in Europe, where harsh seasons led to the destruction of crops. Laki is even believed to be responsible for the famine which contributed to the French Revolution. There’s no need for alarm, though, as we currently don’t have another Laki on our hands.

The Scientific Advisory Board for the Icelandic Civil Protection, which is comprised of scientists from the Icelandic Meteorological Office and the Institute of Earth Sciences from University of Iceland, along with representatives from the Icelandic Civil Protection and the Environment Agency of Iceland, have released a list of the most likely progressions. Of those, the following three scenarios are considered most likely:

The Holuhraun eruption could decline gradually and subsidence of the Bárðarbunga caldera could stop, resulting in no more eruptive activity in the area for the time being.

Large-scale subsidence of the caldera could occur, prolonging or strengthening the Holuhraun eruption. In this situation, it’s likely that the eruptive fissure would lengthen southwards Dyngjujökull, resulting in a glacial flood and an ash-producing eruption, possibly affecting air traffic. It’s also possible that eruptions could develop in other locations under the glacier.

Large-scale subsidence of the caldera could occur, causing an eruption at the edge of the Bárðarbunga caldera. Such an eruption would melt large quantities of ice, leading to major flooding, accompanied by ash fall that could affect air traffic.

Other scenarios cannot be excluded, and scientists are constantly monitoring the area and the situation as it changes on a day-to-day basis.