During the night there was an earthquake deep on the Reykjanes ridge. This earthquake had the magnitude of 4.8 according to automatic result from EMSC.
Due to earthquakes location there is not a lot of details on it. But this location on the Reykjanes ridge has been seeing some activity in the past few months. This might well just be normal tectonic activity for this area. More information on this earthquake can be found here.