Tick Tock – Supervolcano is getting closer

Katla – the icelandic “supervolcano” – is building up magmatic pressure. The term supervolcano is not a correct term – supervolcanos, like the ones in Yellowstone National Park and Toba are supervolcanos with VEI-8. VEI stands for Volcanic Explosivity Index. But Katla is one of the bigger volcanos in the world – and it’s magma chamber is approximately 10 cubic kilometers – enough for a VEI-6 to VEI-7 eruption. Iceland is built up from a weakness in the Earth’s crust on the Mid-Atlantic Ridge, where The North-American Plate and The European Plate  move apart – travelling respectively in a westerly and easterly direction.

British Airways' "Speedbird 9" lit up by flying through volcanic ash in 1982 - Photo: Wikimedia Commons

Lately there has been a quite dramatic increased geological activity in the area. In April last year another volcano on Iceland erupted. Eyjafjallajökul – which is also situated underneath a glacier (jökul is the icelandic word for glacier) erupted violently. The combination of melted rock and water from the glacier gave a violent steam production, blowing hundreds of thousands of tons of volcanic ash several kilometers up into the atmosphere. Unfortunately this halted the airline traffic – I really don’t know why. The concentration in Europe was never enough to damage aircraft engines like the Gulunggung incident with British Airways Flight 9 in 1982 – which gave rise to the famous Gulunggung Gliding Club. But then again – governmental bodies have a tendency to act upon hunches more than facts.

Katla's last major eruption in 1918 - Photo: Wikimedia Commons

Still the Eyjafjallajökul volcano eruption of last year was enough to give a pungent smell of sulfur in Narvik one rainy afternoon 1,780 kilometers away from the volcano. In recorded Icelandic history Eyjafjallajökul has usually erupted just before Katla. Katla has – luckily – erupted more or less with intervals of 50 years since the year 874 AD. Luckily because every eruption reduces the pressure in the magma chamber, preventing even more violent eruptions. The last major eruption was in 1918. But the pressure has since been released some through a small eruption in 1955. Another clear indication is (usually?) a strong earthquake a few hours before the eruption. At least that’s what the Icelandic Sagas – historic tales, talks about. Katla is as such on overtime.

So – how dangerous is this? Well, I hate to say this – but a full eruption from Katla is very dangerous. Such violent volcanic eruptions is known to have blocked out the sunlight on the Good Mother Earth significantly for years.

The good news is – that global warming wouldn’t be an issue for quite a number of years. The bad new is, that crops need sunlight to grow. Reduced sunlight means reduced food-supply in general.

The other bad news, especially for people in Iceland, is the lahars – flash floods of melted glacier water that will effectively block roads and isolate communities. And there is the ash – blocking the sun, falling in Iceland the ash layer can reach several meters. Even in Continental Europe there will be a detectable amount of ash on the ground. The ash is rich in fluorine which – in previous eruptions – has shown to be a deadly toxin to both livestock and humans.

Should we worry? Well, I don’t! We live on a “living planet” which is formed by a dynamic geology. Volcanos erupt. That’s a fact. Worrying about it is no good. Just be thankful for every day Mother Earth isn’t clearing her throat!

10. September 2011 | Categories: Geophysics, Physics | Leave a comment