The pleistocene volcano of Fagradalsfjall has started a phase of uncertainty due to a medium sized tectonic swarm associated with the volcano. At the time of writing there have been around 400 earthquakes ranging up to M4.0 in size. Fagradalsfjall last erupted during the last glacial period in Iceland.
The earthquake swarm is fairly intense for the location, but not unheard of in the region. All earthquakes so far have been tectonic, but in Iceland that can change if a swarm is prolonged.
As of now there are no signs that an eruption is near, but we need to wait a couple of days for GPS-stations to catch up. It also depends on how prolonged the swarm will be.
There has been no intrusion as indicated by the plots since 1997 in this location. Judging from the plots by Andrej Flis this is a magmatic intrusion from depth. This is supported by later earthquake signatures. So far 5 earthquakes are M3+ and 1 is M4.
More news, if any, will follow on this site. We also hope to be able to present plots of the earthquake swarm later on.
And a video also made by Andrej Flis, which shows the swarm in 3D. More graphics will be produced in the coming days, as IMO updates their earthquake catalogue with new data.