After an initial spatter of information of the de-icing of Lake Öskjuvatn things are now coming to a full Easter stop.
After going through the records for earthquakes during the winter up until now one can easily see that there has not been any elevated level of earthquakes. Regarding harmonic tremor episodes, yes there have been a few short episodes that can be interpreted as such, but not a lot really. Also the GPS readings have been fairly consistent.
In reality there are not that many signs of an upcoming eruption. First of all Askja deflated from the onset of the Krafla eruption up until 2007 when an inflation started according to gravimetric readings. Together with GPS readings an inflation was spotted in the center of the old caldera, and a likely dyke intrusion trending towards (possible all the way into) Herdubreid volcano.
That inflation started a series of earthquake swarms, predominantly in the Herdubreid volcano. But, during the winter there seem to not have been a lot of activity, and this makes the de-icing of Öskjuvatn a bit surprising to say the least.
Most likely one of the quakes gave water a path down to a heated area closer to the magma or down to remnants from the 1875 eruption. This in turn most likely caused a new sub-surface geothermal source to heat up the lake. All we can say is that the amount of energy released into the water is substantial, and that it has been warming the lake rapidly during the last few weeks.
Currently there is not much pointing towards an eruption. There are no persistant earthquakes, there is no elevated tremor level, and there is no rapid movement in the GPS:s in the vicinity. The last thing should be taken with a large pinch of salt. The GPS:s of Iceland are really hard to interpret. More about the GPS:s and how to read them will be coming I hope in an upcoming post from someone who actually knows what she is talking about.
Anybody hoping for an Easter-eruption to cure their boredom should go and start painting eggs instead. We will know when and if a final run-up phase starts, and then it is most likely weeks before the actual eruption starts. So, do not expect Askja to blow anytime soon. Otherwise all we can do is waiting, for Askja in general, and for the IMO report after their Tuesday visit.