Bardarbunga is one of the most important volcanic systems in Iceland. The central strato volcano lies under the Vatnajökull glacier. The ice above the volcano is about 800 m thick. It covers a 10 km wide caldera at the summit of Bardarbunga. From the central volcano extends a nearly 150-km-long fissure system. This spreads in SW-NE direction. In the southwest lies the fissure system of Veidivötn. It reaches almost to Torfajökull. In the northeast the Trollagigar fissure system extends close to Askja volcano.
Bardarbunga is associated with several volcanic systems. 40 km southeast lies the Grimsvotn volcano and northeast are the subglacial volcanoes Kistufell and Kverkfjöll.
The central volcano Bardarbunga is the second highest mountain in Iceland and is 2009 m high. The summit area of the volcano is occupied by a caldera. It has a diameter of 10 km and is 700 m deep. The caldera is completely filled with ice. The caldera rim is located at 1850 m altitude, the ice cover above the rim is more than 160 m thick. Due to the remote location and the ice cover Bardarbunga was only discovered in 1973 on satellite photos. Today we know that some of the strongest eruptions Islands emanated from this volcano.
The greatest eruption of Bardarbungas took place about 9000 years ago and created Iceland's largest lava field: Þjórsárhraun. It covers an area of 950 square kilometers and has a volume of 21 cubic kilometers. This eruption came from the Veidivötn-fissure system. From this system came also the most explosive eruption of Bardarbunga in 1477. The eruption had a VEI 6 and produced rhyolite.
Larger subglacial eruptions occurred in the area of the central volcano in the 18th century. Another eruption was detected in 1864. After that eruption, the activity shifted to the volcano Loki-Fögrufjöll. Here the last saved eruption took place in 1910.
In 1996 an earthquake from an eruption of the Grimsvotn triggered an eruption under Bardarbunga. After the earthquake, the subglacial fissure Gjalp opened and the eruption started there.
On August 29, 2014, a small eruption occurred. 4 km north of the central volcano Bardarbunga an eruption fissure was opened that oozed out of the lava. This eruption lasted only a few hours. 2 days later another eruption started at the same fissure. This became the largest effusive volcanic eruptions since the Laki eruption in the year 1783.