From the Icelandic Met Office:

Two M5 earthquakes took place in Bárðarbunga caldera during the night:

A magnitude 5.3 earthquake occurred at 5 km depth just after midnight, at 00:09. Its origin was at the northern rim of the caldera. Another earthquake, magnitude about 5, occurred at 05:33 and originated at the southern rim. These are the strongest events measured since the onset of the seismic crisis at Bárðarbunga and the strongest since 1996 (the Gjálp eruption). The magnitude is already confirmed by the European EMSC network and the GEOFON network of GFZ Potsdam in Germany.

Probably, earthquakes near the Bárðarbunga caldera are a consequence of adjustment to changes in pressure because of the flow of magma from under the caldera into the dyke which stretches to Dyngjujökull, more than 25 km away.

Great seismic activity is also near the intrusive dyke in Dyngjujökull. The activity is concentrated at the section which advanced northwards yesterday morning. Analysis shows that the origin of the quakes, there, has migrated a little towards north. Their depth is mainly in the range of 8-13 km. The largest earthquake in the Dyngjujökull area was 3.5 at 04:39.

No signs of tremor, indicative of eruption, were detected during the night.

Map: Icelandic Met Office.