Sustained seismic activity has been gradually increasing in Bárðarbunga and its associated northern fissure system for a seven years' period, starting in 2007 and leading to an eruption only towards the end of 2014. This activity decreased after the Grímsvötn eruption in 2011, but later returned to a similar level as before the eruption. The prior eruption was in 1910. There has been frequent volcanic activity outside the glacier to the southwest in the highlands between Vatnajökull and Mýrdalsjökull, and also to the northeast toward Dyngjufjöll.