What is Katla doing and should I be worried?

I wanted to do this as a video but I just can’t talk to a camera. I pressed the button and sat and stared at it and pulled faces and couldn’t speak. I’m a writer, not a talker, so I’m writing it instead. Let me add that I am in no way qualified to discuss whether or not we should be worried about a volcano. I am nothing but an enthusiast and at the end of this, I link you to some more reliable sources.

What is Katla?

Katla is a volcano on Iceland’s south coast. She’s next-door-neighbour to our old favourite Eyjafjalljökull. If you don’t remember Eyjafjalljökull, let me remind you.

Eyjafjalljökull is a volcano under a glacier. It erupted in 2010, sent untold amounts of ash into the atmosphere and shut down air traffic across Europe throughout April and May 2010. The two systems are linked – an eruption in Eyjafjalljökull has historically, more often than not, been precursor to an eruption in Katla.

Katla is ten times the size of Eyjafjalljökull. The ice cap is much bigger and it’s the ice that causes the problem. When magma – rock from below the surface of the Earth heated to the point where it is not just melted but full-on liquid – hits a colossal amount of ice, it explodes and it creates ash.

Are we expecting an eruption?

In short, yes. Katla has had major eruptions approximately twice a century ever since Iceland’s been settled. The last one was in 1918. By our reckoning, she’s overdue and there has been a lot of seismic activity around her recently – earthquakes indicating that there’s movement in the magma. This Friday and Saturday there were nearly 300 earthquakes within forty-eight hours. Yes, most of them too small to notice without specialised equipment but a good few over magnitude 3, which you would be able to feel. She’s been put on yellow alert, tourists are to keep away and flight paths have been altered to not go directly across anymore.

So, should I worrry?

For the time being, no. There are three possibilities here as to what’ll happen.

Number one, the tremors will just stop and nothing more will happen. That’s most likely. Katla’s been rumbly a couple of times in the last few years and nothing has come of it. Think of it as the volcano turning over in bed and going back to sleep.

Number two, there will be a small eruption that doesn’t break through the glacier. It’ll melt some of the ice directly above it, inside the glacier and that will emerge as a jökulhlaup – a glacial flood, where that melted water rushes out. It might happen as little more than elevated levels in smallish local rivers, with a small amount of smelly poisonous volcanic gases, or it might happen as a tsunami, tearing away roads, bridges and parts of the glacier, littering the plain with blocks of ice the size of houses. We literally don’t know.

Number three, there will be an eruption.

3A – it will probably (not definitely!) be a big eruption similar to Eyjafjalljökull’s 2010 one – billions of tons of ash, flights disrupted worldwide, glaciers and mountainsides torn off in jökulhlaups. A big deal, in other words. Katla can potentially close down flights for years. And unless she releases some pressure, there’s a reasonably good chance this will happen at some point in our lifetime. Don’t let me scaremonger. This is what I’ve been told is likely.

3B – it does what Bárðarbunga did. Bárðarbunga is a volcano on Vatnajökull, Iceland and Europe’s biggest glacier, give or take Greenland. Katla, horrifying as she is, has established a pattern of semi-regular explosive eruptions. We don’t know exactly when she’ll go but we more or less know what she’ll do. Bárðarbunga is less predictable. When it started rumbling in 2014, no one knew what was going to happen, whether this was going to be a Katla-style end-of-the-world-as-we-know-it eruption, whether it would be explosive or effusive or big or dramatic or a couple of puffs of smoke. In fact, what happened was that the magma pushed its way underground to the north and erupted from a fissure in the middle of the Highlands, a pretty effusive eruption with lava fountains and rivers. Really hard to get to and generating a lot of poisonous gases but otherwise, pretty and harmless. If you weren’t in Iceland and weren’t interested in volcanoes, you probably never knew it even happened. I’ve been keeping an eye on Katla and no one has mentioned this as a possibility. Therefore it’s pretty unlikely but it’s not 100% impossible, I don’t think.

You didn’t answer. Should I be worried?

I don’t think so, not at the moment. Right now it looks like it’s all going quiet. Katla’s rumblings have died down again and the worst Iceland seems to be preparing for at the moment is a possible jökulhlaup. I mean, don’t take me as gospel. I have no volcanology credentials or qualifications whatsoever besides a D in A Level Chemistry, I just enjoy reading about eruptions and visiting lava fields (take me on as a volcanology intern! Please!).

Where can I find things out from people who actually know what they’re talking about?

I’d start with the Icelandic Met Office, which monitors seismic activity. Then there’s the Global Volcanism Program and the Iceland Review site, which is Icelandic news in English. Twitter-wise, I recommend Thorbjorg Agustsdott, Simon Redfern and Dave McGarvie who are all proper qualified scientists of slightly assorted disciplines, who all know about volcanoes – to the point where I’m pretty sure they all visited and worked on the 2014 eruption, so they know their stuff.

In the very unlikely event there is an eruption, I will be very excited and also terrified.