The main edifice of Bardabunga volcano is located under Icelands largest Glacier, the Vatnajökull. The volcano is about 2009 meters high and has an up to 10 km wide and 700 m deep summit caldera. It is considered linked to the Veidivötn and Trollagigar fissure systems, which extend about 100 km SW and 50 km NE, respectively. The Bardarbunga volcanic system, encompassing the associated fissures, has been the site of a number of notable effusive and / or explosive basaltic eruptions. An eruption in 6600 BC emplaced the largest lava field of the Holocene period, covering nearly 1000 square kilometers with a volume of over 20 cubic kilometers. The V.E.I. 6 Veidivötn eruption of 1477 is considered the most powerful icelandic eruption during historical times and produced about 10 cubic km of tephra. The most recent eruption, prior to 2014, was in 1910, and at least 20 eruptions having occurred in the past 1000 years. This number could however represent a vast underestimate since many small subglacial eruptions may have occurred. No large eruptions have been attributed to the central Bardabunga volcano in the last 1100 years. The subglacial setting of parts of the system presents a major hazard since major flooding may occur as a result of eruptions, and violent activity can be triggered by interaction of groundwater with magma. Further, large effusive deposits can block or redirect river drainages. Lava from the 2014 eruption started to flow into the bed of Jökulsa a Fjöllum river on 7. September.
Holuhraun Fissure Eruption (Phase II)
The 2014 Holuhraun fissure eruption can be attributed to unrest at Bardarbunga. The extensive Holuhraun lava field was last site of a significant effusive eruption in 1797. The 2014 eruption has so far involved two subaerial eruptive phases, the first short-lived fissure eruption occured along an over 0.5 km long fissure in the early hours on 29. August 2014. The second phase of the eruption (herein Phase II) commenced on 31. August 2014 and involved reactivation and extension of the Phase I fissure, leading to an about 1.5 km fissure along which intensive lava fountaining of fluid basaltic lava could be observed. On Sept. 5, two smaller fissures formed further south (nearer to the Bardabunga edifice), yet activity there was short-lived. Activity gradually focussed on the southern sector of the main fissure and became concentrated in a chain of several active craters. This can be seen in images below from overflights on Sept.11 & 13. It is probably that a subglacial eruption occured on 23. August and preceeded the abovementioned eruptions. Subsidence features in the Dyngjujökull glacier (a branch of the Vatnajökull glacier complex) suggest that melting took place underneath.
VIDEO OF HELICOPTER FLIGHTS TO FISSURE INCLUDING SPECTACULAR LAVA FOUNTAINS:
Lava flow heading north along axis of fissure to Jokulsa a Fjollum river
Lava field as it interacts with Jokulsa a Fjollum river
Images from September 11 overflight. (Active cone shown in detail was no longer active on September 13)
Cones along fissure
Cones along fissure
Close-up cone in foreground of image to left
Lava flow emitted from foot of cone
Fissure and lava field growing around it
Fissure and lava field with airplane above
Visitors wishing to view the fissure should obtain local information. Access to the site of the eruption is strictly regulated with a large (well controlled) exclusion zone in place. Small aircraft flights to the fissure may be arranged from e.g. Myvatn airport, whilst several helicopter companies, such as volcanoheli.is (recommended) also offer flights from varying locations. Iceland visitors should also keep an eye out for Northern Lights. These appear much fainter to the naked eye than would appear from images, as the eyes are not very sensitive to colour in the dark.
Gas clouds above fissure illuminated by eruption, viewed from Modrudalur
Northern Lights (Aurora Borealis), commonly seen in Iceland
REAL-TIME VIDEO OF AURORA BOREALIS:
Roadblock at turning off main ring road
Road-block with 4WD patrol vehicle
Matthias's Raven R44 helicopter of volcanoheli.is
Doors off, ready for flight. Gas from eruption in distance above heli nose