[1] The central volcano has a rim that rises to about 2,000 m (6,600 ft) above sea level,[a] making it the second highest mountain in Iceland, being lower than Hvannadalshnjúkur.

[7][c] Sustained seismic activity had been gradually increasing in Bárðarbunga and its associated northern fissure system for seven years starting in 2007 and leading to an eruption towards the end of 2014.

[1] While the central volcanoes of the Bárðarbunga volcanic system are under the western edge of the Vatnajökull ice cap, the system's northern fissure swarm and lava flows extend around the southern flanks of the Askja volcano and the southern fissure swarm extends past the north-west of Torfajökull and almost reaches Tindfjallajökull.

[1] It is now known that within the area of the rhyolitic caldera of Torfajökull there are younger extrusives that involve basaltic magma mixing events by lateral propagation,[c] from the fissure swarm of Bárðarbunga's volcanic system.

[3] Studies of tephra layers have shown that a number of eruptions have occurred beneath the glacier, probably in the northeast of the crater or in Bárðarbunga.

[15] The following day, the aviation risk was lowered from red to orange and the statement that there was an eruption in progress was retracted.

Then, a new fissure eruption breached the surface between Bárðarbunga and Askja, in the Holuhraun lava field, in the early hours of 29 August.

[19] Nevertheless, the gas pollution still existed, and the area north of Bárðarbunga, including volcanoes Askja and Herðubreið, still remained closed for visitors.

[21] This was the largest earthquake under this region of the Vatnajökull icecap since the 2015 eruption and was associated with isolated smaller fore- and aftershocks but no other markers of potential volcanic activity.

[22] On 14 September 1950 a Douglas C-54 Skymaster aircraft belonging to the Icelandic airline Loftleiðir crash landed on the Vatnajökull glacier at Bárðarbunga during a cargo flight from Luxembourg to Reykjavík.

After two days the crew managed to reach the emergency transmitter in the plane's rubber liferaft and send out a distress call which was picked up by the Icelandic Coast Guard vessel Ægir.

The C-54's cargo included the body of a deceased United States Air Force (USAF) colonel, prompting American assistance.