It Stirs!

Firstly I should apologise for the lack of updates recently – I’ve been quite busy elsewhere, and besides the eruption had been largely stable. But much like my schedule, the eruption has changed again, so here’s an update as to what’s going on with our pet volcano at the moment.
After settling into a nice Strombolian phase (small explosions casting blocks and bombs of lava into the air) for a couple of weeks, the eruption has changed back to a more explosive type in recent days – something more akin to what we saw at the beginning of this eruption.
What does that mean? Well, it means no more pretty lava bombs flying out, and a lot more ash. Indeed, the plume is thought to have reached an altitude of 9 kilometres yesterday and is a lovely dark grey once more, indicating that it is ash-rich. And what does THAT mean? Well, it means Europe’s airspace could be in for a kicking again, depending on wind directions. Trans-Atlantic air routes are already being disrupted. Stay tuned for more information on this – things could get messy once again. In more local terms, things have already gotten pretty messy – there’s a lot of ash and tephra fall in the vicinity, which is coating everything in fine powder and turning everything black. My heart goes out to the farmers especially, who were just beginning to clear up from the last round.
This change in activity has put a stop to the lava flow that has been slowly making its way downhill beneath Gígjökull recently. I was expecting it to expose itself fairly soon, but it’s been stationary for the past couple of days because the effusion of fluid lava from the vent has basically dropped to zero. It’s also reduced the amount of meltwater flowing out – it’s not immediately obvious if there just isn’t much melting going on, or if it’s all building up somewhere ready to be released in a jökulhlaup. Time will tell, I guess.
So, why the change in activity? Honestly, we don’t yet know. My guess is that the magma coming up from below (a fresh batch has been detected probably making its way up from very deep down in recent days) is making contact with some thicker, silica-rich magma inside the volcano, and that is causing a purely explosive eruption. It could also be additional meltwater interaction (a phreatomagmatic eruption once again), although there doesn’t seem to be so much white steam present this time.
Questions abound, not only about why this is happening, but also about what will happen next – and honestly we don’t really know that either. It could remain like this, spewing out lots of ash, for a long time. It could go back to Strombolian explosions. It could explode a lot more violently. It could stop altogether… although there is no evidence of this happening any time soon.
Interestingly there does seem to be evidence of something going on underneath, with GPS readings showing that the volcano is inflating slightly in some areas. This is mostly likely due to that new batch of magma from deep below, but I wouldn’t totally rule out some kind of development in the coming days.
So to tie everything together – less lava, more ash, probably a lot more delays. And still nothing underneath Katla, before you ask…
‘Til next time…
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