At 02:55 UTC today (18.12.2012) there was a magnitude 3.3 earthquake in Bárðarbunga volcano system. Earthquakes are common in this area so this activity is no surprise. Origins of this earthquakes are due to tectonic movements in the area. Not magma related changes.
Green star marks the magnitude 3.3 earthquake in Bárðarbunga volcano system. Copyright of this image belongs to Icelandic Meteorological Office.
Aftershocks have followed this earthquake. So far the largest one got the magnitude 2.2. More earthquake activity can be expected in this area. But that is normal and not unexpected.