|Elevation||2,009 m (6,591 ft)|
|Prominence||550 m (1,804 ft)|
|Type||Subglacial volcano/Icelandic stratovolcano|
|Age of rock||approx. over 100 years|
Bárðarbunga (pronounced [b'aurðarbuŋka]) is an Icelandic stratovolcano, or subglacial volcano located under the ice cap of Vatnajökull glacier, rising to 2,009 metres (6,591 ft) above sea level, making it the second highest mountain in Iceland, just about 101 metres (331 ft) lower than Hvannadalshnjúkur.
Bárðarbunga is a large and powerful stratovolcano, it is also Iceland's largest volcanic system, considered to be close to 200 kilometres (120 mi) long and up to 25 kilometres (16 mi) wide.
The Bárðarbunga caldera is about 70 square kilometres, up to 10 kilometres (6 mi) wide and about 700 metres (2,300 ft) deep. The surrounding edges rise up to 1850 metres but the base is on average close to 1100 metres. The volcano is covered in ice, hiding the glacier-filled crater.
Bárðarbunga was a little-known volcano in Iceland because of its remote location, far away from settlement, and infrequent eruptions. Bárðarbunga's highest point is 2,009 metres (6,591 ft) high and is the second highest mountain in Iceland.
Many tephra layers originally thought to belong to other volcanoes have in the recent studies proved to be from Bárðarbunga. The Gjálp fissure eruption in 1996 revealed that an interaction may exist between Bárðarbunga and Grímsvötn. A strong earthquake in Bárðarbunga, about 5 on the Richter scale, is believed to have started the eruption in Gjálp.
Sustained seismic activity has been occurring in Bárðarbunga for some years without an eruption, thus the volcano is still active.
In historic times there have been large eruptions every 250–600 years. Thjorsarhraun is the largest holocene lava flow on the earth, it originated from Bárðarbunga about 8500 years ago, with a total volume of more than 21 cubic kilometers with some estimates saying as high as 30 cubic kilometers, it covers approximately 950 square kilometers. The largest eruption from Bárðarbunga had a VEI of 6, many smaller-sized eruptions have been recorded in the past 10000 years.
Many large prehistoric eruptions have occurred southwest of the glacier and two after settlement in Iceland, Vatnaöldur eruption about 870 and Veiðivötn eruption 1480. Both were very large eruptions that would have major effects on life in Iceland and neighboring countries were they to repeat in modern times.
Smaller eruptions are frequent northeast of Bárðarbunga in an ice-free area called Dyngjuháls. Such an eruption last occurred in 1862-4.
Studies of tephra layers have shown that a number of eruptions have occurred beneath the glacier itself, probably in the northeast of the crater or in Bárðarbunga. These eruptions appear to follow a cycle, several eruptions were in the glacier between 1701–40 and since 1780. There has been an eruption in the glacier or the system since 1864. Frequent earthquakes in Bárðarbunga indicate that the volcano will erupt sooner or later.
Dangers from eruptions
Large volcanic fissure eruptions occur every 5–800 years in Iceland. They often occure in the Veiðivötn area, south-west of the Bárðarbunga central volcano. Such an eruption would endanger many of Iceland's hydroelectric power plants as each eruption changes the landscape dramatically. Tephra from a large eruption from the Bárðarbunga volcanic system could affect flight traffic and temperature in northern parts of the world.