Today (Des. 20th) at 04:57 a M3.7 earthquake was detected in the northern part of the Bárðarbunga caldera and another M4.3 earthquake followed at 05:29. Several earthquakes have followed, but there are no signs of volcanic tremor. Written by a specialist at 20 Dec 05:50 GMT
(Later recalculated as 4.1 and 4.4)
See:
Visualisation by Baering's 3DBulge: http://baering.github.io/
