Report on Bardarbunga (Iceland) — 27 August-2 September 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 27 August-2 September 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Bardarbunga (Iceland). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 27 August-2 September 2014. Smithsonian Institution and US Geological Survey.
64.633°N, 17.516°W; summit elev. 2000 m
All times are local (unless otherwise noted)
During 27 August-2 September the Icelandic Met Office reported ongoing seismic activity at Bárdarbunga volcano. On 27 August an overflight showed a 4-6-km-long row of cauldrons 10-15 m in diameter S of Bárdarbunga. On 29 August a small fissure eruption started in Holuhraun along an old fissure about 600 m in length north of Dyngjujökull. Lava again erupted starting on 31 August along a 1.5 km long fissure. The Aviation Color Code was raised to Red and lowered to Orange later in the day. On 1-2 September a white steam and gas plume rose 4.5 km (15,000 ft) a.s.l. and drifted 60 km to NNE and ENE. Lava flowed N and lava plumes rose tens of meters. There was a noticeable decrease in seismicity from 500 earthquakes on 1 September to 300 earthquakes on 2 September. Earthquakes up to magnitude 4-5.4 have been detected at or near the volcano. On 2 September the lava had covered 4.2 square kilometers and was 4.5 km from the glaciers edge. The London VAAC reported no ash plumes associated with the fissure eruptions. The Aviation Color Code remains at Orange.
Geologic Background. The large central volcano of Bárðarbunga lies beneath the NW part of the Vatnajökull icecap, NW of Grímsvötn volcano, and contains a subglacial 700-m-deep caldera. Related fissure systems include the Veidivötn and Trollagigar fissures, which extend about 100 km SW to near Torfajökull volcano and 50 km NE to near Askja volcano, respectively. Voluminous fissure eruptions, including one at Thjorsarhraun, which produced the largest known Holocene lava flow on Earth with a volume of more than 21 km3, have occurred throughout the Holocene into historical time from the Veidivötn fissure system. The last major eruption of Veidivötn, in 1477, also produced a large tephra deposit. The subglacial Loki-Fögrufjöll volcanic system to the SW is also part of the Bárðarbunga volcanic system and contains two subglacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge to the SW. Jökulhlaups (glacier-outburst floods) from eruptions at Bárðarbunga potentially affect drainages in all directions.