Bárðarbunga

Stratovolcano in Iceland

Bárðarbunga

Map of Iceland showing the location of Bárðarbunga.

Geological features near the Bárðarbunga volcanic system (red outlines -note potential overlap with other volcanic systems is only shown in south^[b]). Light violet shows Bárðarbunga associated recent lava fields. Other shading shows:    calderas,   central volcanoes and   fissure swarms,   subglacial terrain above 1,100 m (3,600 ft), and   seismically active areas. Clicking on the image enlarges to full window and enables mouse-over with more detail.

Bárðarbunga (Icelandic pronunciation: [ˈpaurðarˌpuŋka] ^ⓘ, alternative name Veiðivötn),^[4][1] is an active and productive stratovolcano located under Vatnajökull in Vatnajökull National Park which is Iceland's most extensive glacier. 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 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^[3] under the ice cap of Vatnajökull glacier in the Vatnajökull National Park in Iceland. It is one of the six volcanic systems under Vatnajökull.^[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. The caldera is about 65 km² (25 sq mi),^[1] up to 10 km (6.2 mi) wide and about 700 m (2,300 ft) deep.^{[3][5]: 154} 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.^[6] The associated volcanic system and fissure swarm is about 190 km (120 mi) long and 25 km (16 mi) wide.^[1]

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,^[1] and that lateral dyke intrusions may trigger eruptions in adjacent volcanoes.^[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. 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.^[5]: 155 Hamarinn is 20 km (12 mi) to the south-west of the Bárðarbunga central volcano.^[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. The southern lava flows have reached the sea near Selfoss.^[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.^[8]: 2921 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.^[1] 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.^[7][c]

Bárðarbunga is named after an early Icelandic settler named Gnúpa-Bárður [ˈknuːpa-ˌpaurðʏr̥], and literally translates as "Bárður's bulge" or "Bárður's bump" since "Bárðar" is the genitive case of "Bárður".^[9]

Throughout history, there have been large eruptions every 250–600 years. In 1477, the largest known eruption from Bárðarbunga had a volcanic explosivity index (VEI) of 6; there is evidence of many smaller eruptions during the past 10,000 years.^[3]

Þjórsá Lava, the largest Holocene lava flow on earth,^[3] originated from Bárðarbunga about 8,600 years ago, with a total volume of 21^[3] to 30 cubic kilometres and covering approximately 950 square kilometres.^[10]

Many large eruptions have occurred south-west of the glacier; the first occurring since human settlement of Iceland was the Vatnaöldur eruption about 877 ± 2 CE which had a volcanic explosivity index (VEI) of 4.^[11][3]

The Veiðivötn eruption in 1477 is the largest known Icelandic eruption, with a VEI of 6.^[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. There have also been smaller eruptions in an ice-free area of Dyngjuháls [ˈtiɲcʏˌhauls] to the north-east. Eruptions appear to follow a cycle: there were several eruptions in the glacier between 1701 and 1740 and since 1780.

1910 was the last known significant eruption of the Bárðarbunga volcanic system before the 2014 eruptions.^[2][1] It occurred in the Loki-Fögrufjöll volcano.^[5]: 163

The Gjálp fissure vent 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. On the other hand, because the magma erupted showed strong connections to the Grímsvötn Volcanic System as petrology studies showed, the 1996, as well as a former eruption in the 1930s, are thought to have taken place within Grímsvötn Volcanic system.^[12]

On 26 September 2010, an earthquake swarm was recorded with over 30 earthquakes measuring up to 3.7M_W on the moment magnitude scale.^{[citation needed]}

In August 2014, a swarm of around 1,600 earthquakes in 48-hours, with magnitudes up to 4.5M_W, ^[13][14] was followed on 23 August by the USGS Aviation Color Codes being raised from orange to red, indicating an eruption in progress.^[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.^[16] However, later aerial observations of glacial depressions southeast of the volcano suggested that the now-retracted report of an eruption had been correct and that a short eruption did occur under the ice, but the lack of further melting indicated that this eruption had now ceased. Then, a new fissure eruption breached the surface between Bárðarbunga and Askja, in the Holuhraun lava field, in the early hours of 29 August.^[17] This was followed by a second fissure eruption in the Holuhraun area, along the same volcanic fissure, which started shortly after 4 am on 31 August.^[18]

The eruption emitted large volumes of sulphur dioxide and impacted air quality in Iceland. There was no effect on flights outside of the immediate vicinity as the eruption hadn't produced a significant amount of volcanic ash.

On 28 February 2015, it was officially reported that the eruption was over.^[19] Nevertheless, the gas pollution still existed, and the area north of Bárðarbunga, including volcanoes Askja and Herðubreið, still remained closed for visitors.

On 16 March 2015, the area north of Bárðarbunga was opened for visitors, excluding the new lava field and the area within 20 metres around it.^[20]

On 21 April 2024 a M_w 5.3 earthquake occurred in the Bárðarbunga volcanic system.^[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.^[23] There were no fatalities, but damaged radio equipment left them unable to communicate their location. 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 same day a search and rescue Catalina aircraft, named Vestfirðingur, spotted them. The C-54's cargo included the body of a deceased United States Air Force (USAF) colonel, prompting American assistance. A USAF C-47 equipped with skis landed on the glacier but was unable to take off again, so it had to be abandoned. After six days both crews were rescued by a ski-patrol from Akureyri. Later Loftleiðir bought the stranded C-47 from the USAF for $700.^[24] In April 1951 it was dug out of the snow and towed down the mountain by two bulldozers, where it was started and flown to Reykjavík.^[23][25][26]

• Timeline of volcanism on Earth
• Volcanism of Iceland
  • List of volcanic eruptions in Iceland
  • List of volcanoes in Iceland

• Bárðarbunga in the Catalogue of Icelandic Volcanoes
• 3d map of volcanic activity and webcam at Bárðarbunga updated live from IMO
• Bárðarbunga live webcams feed
• Michigan Tech Geological Engineering and Sciences – Bárðarbunga/Grimsvötn Volcanoes
• Seismic activity in the Vatnajökull region
• Bárðarbunga volcano livestream
• (The Bárðarbunga System), pre-publication extract from The Catalogue of Icelandic Volcanoes
• Official Website of Vatnajökull National Park