Six o’clock yesterday (tuesday) a small swarm of earthquakes started at Reykjanes Ridge, it started with a 3.8M at 05.48 in the morning. That quake was followed by a limited number of quakes that trended downwards in strength.
Earlier today (wednesday) the swarm returned and picked up strength and amount of quakes quite considerably.
These earthquakes are visible on all SILs in iceland. I have here though chosen to show what it had as effect on the Hekla Borehole strainmeter plot. Look at how it produces first two large spikes, and then a bell-curve as energy increases, and then decreases in the swarm.
Reykjanes Ridge is a sub-aquatic volcano as well as a part of the MAR. It has had numerous eruptions, sometimes producing ephemereal islands, and some islands that has stayed above surface.
There are though no sign of this being an eruption, at least yet there is not telltale harmonic tremoring. So, it is most likely a normal tectonic earthquake episode.
Just to put this into perspective. The current swarm of earthquakes at Reykjanes Ridge has during the last couple of hours (as I am writing this) released more energy than Katla has done in the last half a year, and the amount of energy released from the last 3 months of activity at El Hierro, put together. Awesome come to think about it.