Around 17:10 UTC an earthquake swarm did start in Katla volcano. This earthquake swarm is focused inside the Katla caldera at small point. The one earthquake that I have so far been able to record was an long period earthquake, but that suggests that this earthquake was created by magma movement. At current time I am not sure from where this earthquake did originate from. But from Goðabunga area in Katla volcano this types of earthquakes are common and no surprise at all.
At current time I do not know what this means for Katla volcano. But so far no increase in harmonic tremor has been detected on the seismometers around Katla volcano. But that might not start at current time, as harmonic tremor is only going to increase when magma starts to move inside the Katla volcano, like did happen in Grímsfjall volcano few weeks ago.
The location of this earthquake swarm strongly suggests that what is going on in Katla volcano is an dike intrusion in the Katla caldera. If that is powerful enough to start an eruption is an question remained unanswered at current time.
Area of activity is marked by the earthquakes. Looks like an dike intrusion into Katla caldera. Copyright of this picture belongs to Icelandic Met Office.
I am going to update or post new blog posts as this continues to develop. I do not think that this events are over. But it is hard to know for sure, since volcanoes are impossible to predict.
Post post updated at 18:39 UTC.
@Jack Thank you for that . A nice clear basic visual explanation of these terms. Appreciated.
And a May – June perspective plot for the quakes in and around Katla.
http://i56.tinypic.com/2ahzcl0.png
Lurking you could do a plot to this swarm in Prestahnukur. It’s very interesting and continues. The last earthquake is a shallow one: Saturday
18.06.2011 17:46:53 64.584 -20.608 2.0 km 2.4 90.07 17.8 km SE of Húsafell
Se the new thread.
Jon, take a look at the Godabunga (god) plot and see what’s happening in the 2-4hz band. Something has just increased. The 1-2hz trmor plot also looks to be on the increase, although it’s hard to tell. Any better information?
It is hard to know for sure what this is. But there is something else also happening on other stations around Katla volcano. I do not know yet what that is.
New blog post is up! 🙂
Thanks Jon, very helpful.
@Raving: Nothing against James, but You were right to make Your last post. Academy is nice and let’s respect it, but an academic degree or job doesn’t make people better than anyone else – been there long enough to know… 🙂 Let all of us give what we can best – and sometimes passion is just what it takes to make things move, and of this Jon has clearly enough!
Katla WILL go off. It’s a Shame that the Katla Webcam is Still down. It’s just a Question of Time. The Past has shown us that this Volcano goes off at the End of the Summer & During Autum. This is a Clear Sign that movement or a Build up is happening beneath the Mýrdalsjökull glacier.
Also, there hasn’t been a Violent Eruption at Katla since 1918 which could mean a Bigger build up of Magma, & thus points towards a Larger Eruption. A VEI5 or even a VEI6 Perhaps. Usually she has erupted twice or more per century. But it’s almost an entire Century now.
We should Prepare for the worst. After all, this year so far has show us that the world is not reacting positively to our lack of care.