A man of science explores the options
Bárðarbunga: it’s going to explode, you’re going to be trapped in Iceland for six months and you might die a horrific, fiery death. Why? Because such grand claims make good headlines and sell papers, that’s why. Personally, I’ve always believed more in science than sensationalism, so if you’ll permit me, I’d love to spread a little of that…
The situation at Bárðarbunga is quite complex and, as such, presents a range of possibilities. Most of these possibilities are exciting; some of them are dangerous; none of them are terrifying. Let’s take a look at the first possibility: there is no eruption. Yep, that’s right—it might not even happen! As I write this, the magma is currently making its way towards the surface in what we call a dike (stop sniggering, you at the back)—rather than coming straight up, the magma is following a line of weakness in the crust some 35 or so kilometres long (and growing!). Prior to the 2010 Eyjafjallajökull eruption, there were
several ‘false starts’ in previous years, where dikes just petered out before they hit the surface. There’s nothing to say that couldn’t happen here.
The second possibility is that we see something like the first part of the 2010 eruption. As the magma ascends, it appears to be moving slowly northwards, away from Vatnajökull. If the dike were to reach the surface away from thick ice cover, it could result in a spectacular fire-fountaining eruption similar to the one that drew so many tourists in 2010. This probably wouldn’t produce much ash, so risks to aviation would be small, and it would be unlikely to have effects much beyond the immediate area. Marshmallows, anyone?
Another possibility has the potential to be somewhat more troublesome, although it’s appearing somewhat less likely as time goes on. If there is an eruption beneath the ice, the hot magma coming into contact with cold meltwater could trigger production of an ash cloud. The eruption at Eyjafjallajökull was exceptional for several reasons—the second stage occurred both beneath the glacier and was of a different, thicker, more gas-rich magma type than the first. Both of these combined created a situation in which the ash produced was very fine indeed, leading to it being carried a long way into the atmosphere. Unlucky for travellers, but a repeat performance is not guaranteed, even in the case of another sub-glacial eruption. Arguably the biggest threat from a sub glacial eruption is that of a jökulhlaup—a glacier outburst flood—but authorities will be ready to evacuate anyone at risk (locals only!) from the area if there is any chance of that.
The final possibility of note is a particularly interesting one, deserving of a whole article on its own (and a whole lot more research on my part!). The dike is actually headed in the direction of the really rather large Askja volcano. We know there is magma built up beneath the Askja caldera, so if this dike were to hit that, it could trigger something much larger than we could otherwise see. However, saying much beyond that right now would be speculation, bordering on scaremongering, so I will refrain…
In summary: don’t worry about it. Many different things could happen, only a couple of them present any cause for concern, and they are unlikely to affect you anyway. Volcanoes are fickle beasts, incredibly hard to predict, and The Daily Mail are going to do a worse job of that than the scientists on the ground. Leave it to the volcanologists—we know what we’re doing. Mostly.
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Our wonderful photographer friend Axel Sigurðsson spent the weekend of the non-eruption eruption flying over the alleged area of geological unrest. See more of those shots at www.grapevine.is
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