Over the past days there have been a quiet streak happening in Iceland geology. This regularly happens and doesn’t mean anything special. This quiet times can sometimes last for up to 10 to 20 days at the longest. The longest quiet time that I did see lasted something close to five weeks. But then activity started to pick up again slowly.
It also happens sometime that quiet period is end with a bang. Then with a ML/Mb 4.0 or 5.0 earthquake and following earthquake swarm. Even if quiet time happens in Iceland sometimes, it does not necessary mean that the year is going to be a quiet one. As we have already seen with Eyjafjallajökull eruption in 2010.
Earlier tonight a second harmonic pulse was seen on Grímsvötn SIL station. This time the harmonic pulse has lasted longer and is still ongoing when this is written. What is creating this harmonic pulse is unclear at this moment. But at current time Grímsvötn lake is full of water. It might well be that the water is on the move and is leaving the Grímsvötn lake. However it is not going to be clear if that is the case or not in the next few hours. I would not be surprised if it goes both ways. That is the water is on the move and that it might not be on the move at all.
The second harmonic tremor seen on SIL station run by the IMO. Picture credit, Icelandic Met Office.
Grímsvötn SIL station. Click here for the full list of SIL station run by Icelandic Met Office.