Bárðarbunga

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Bárðarbunga (Icelandic pronunciation: [ˈpaurðarˌpuŋka] , alternative name Veiðivötn), is an active and productive stratovolcano located under Vatnajökull, which is Iceland's most extensive glacier, in Vatnajökull National Park. The second highest mountain in Iceland, 2,000 metres (6,600 ft) above sea level, Bárðarbunga is also part of the Bárðarbunga-Veiðivötn volcanic system that is approximately 190 kilometres (120 mi) long and 25 kilometres (16 mi) wide.

Bárðarbunga erupted in late August 2014. The eruption style was effusive, which is common in Iceland, but had not been seen for a few years. Lava covered the surrounding landscape northwest of the Vatnajökull glacier.

Bárðarbunga is a subglacial stratovolcano and central volcano under the ice cap of Vatnajökull glacier in the Vatnajökull National Park in Iceland. It is one of the six volcanic systems under Vatnajökull. The central volcano has a rim that rises to about 2,000 m (6,600 ft) above sea level, making it the second highest mountain in Iceland, being lower than Hvannadalshnjúkur. The caldera is about 65 km2 (25 sq mi), up to 10 km (6.2 mi) wide and about 700 m (2,300 ft) deep. The surrounding edges rise to 1,850 m (6,070 ft), but the base is on average close to 1,100 m (3,600 ft). The volcano is covered in ice to a depth of 850 m (2,790 ft), hiding the glacier-filled crater. The associated volcanic system and fissure swarm is about 190 km (120 mi) long and 25 km (16 mi) wide. Bárðarbunga was a little-known volcano in Iceland due to its remote location and infrequent eruptions approximately once every 50 years, but recent studies have shown that many tephra layers originally thought to be from other volcanoes were ejected from Bárðarbunga, and that lateral dyke intrusions may trigger eruptions in adjacent volcanoes. 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. This activity had decreased after the Grímsvötn eruption in 2011, but later returned to a similar level as before the eruption. The previous Bárðarbunga eruption was in 1910. There has been frequent volcanic activity outside the glacier to the south-west in the highlands between Vatnajökull and Mýrdalsjökull, and also to the north-east toward Dyngjufjöll [ˈtɪɲcʏˌfjœtl̥]. The Bárðarbunga volcanic system is associated with a second central volcano Hamarinn which has been classified historically as part of a separate Loki-Fögrufjöll volcanic system. Hamarinn is 20 km (12 mi) to the south-west of the Bárðarbunga central volcano.

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. The southern lava flows have reached the sea near Selfoss. 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, from the fissure swarm of Bárðarbunga's volcanic system. To the west of the central volcanoes is the less active volcanic system of Tungnafellsjökull and to the central volcanoes south west, also under Vatnajökull is the very active Grímsvötn volcanic system. In the 1996 eruption of Gjálp which is usually assigned to the Grímsvötn volcanic system, studies are consistent with the eruption being triggered by a 10 km (6.2 mi) lateral dyke intrusion at about 5 km (3.1 mi) depth from Bárðarbunga, although this is not proven.

Adapted from Wikipedia (CC BY-SA). Photography via Wikimedia Commons.