"An earthquake of magnitude 5.5 shook the area to the northeast of Bárðarbunga this morning at 5:28 am.
The probability of an eruption in Bárðarbunga is now thought to be increased due to a steady lowering of the surface above the volcano's crater. This greatly worries scientists and Civil Protection Department representatives, ruv.is reports.
An eruption in Bárðarbunga, which lies underneath Vatnajökull glacier, could potentially be massive, emitting high quantities of ash into the air, according to geophysicist Magnús Tumi Guðmundsson. The glacial melt water would ultimately break out as a great flood in one of the glacial rivers. This is the scenario which the Civil Protection Department is preparing for."
http://icelandreview.com/news/2014/09/10/bardarbunga-eruption-major-worry