Lava field evolution and emplacement dynamics of the 2014–2015 basaltic fissure eruption at Holuhraun, Iceland

• Published in: Journal of Volcanology and Geothermal Research
• Main Authors: Pedersen, Gro, Höskuldsson, Ármann, Dürig, Tobias, Thordarson, Thorvaldur, Jonsdottir, Ingibjorg, Riishus, M. S., Óskarsson, B.V., Dumont, Stéphanie, Magnússon, Eyjólfur, Gudmundsson, Magnus Tumi, Sigmundsson, Freysteinn, Drouin, V.J.P.B., Gallagher, C., Askew, R., Gudnason, J., Moreland, William, Nikkola, P., Reynolds, Hannah Iona, Schmith, Johanne
• Other Authors: Jarðvísindastofnun (HÍ), Institute of Earth Sciences (UI), Jarðvísindadeild (HÍ), Faculty of Earth Sciences (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier BV 2017
• Subjects: Geophysics; Geology; Volcanology; Lava flows; Jarðeðlisfræði; Jarðfræði; Eldfjallafræði; Hraunrennsli; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/320; https://doi.org/10.1016/j.jvolgeores.2017.02.027

The 6-month long eruption at Holuhraun (August 2014–February 2015) in the Bárðarbunga-Veiðivötn volcanic system was the largest effusive eruption in Iceland since the 1783–1784 CE Laki eruption. The lava flow field covered ~84 km2 and has an estimated bulk (i.e., including vesicles) volume of ~1.44 km3. The eruption had an average discharge rate of ~90 m3/s making it the longest effusive eruption in modern times to sustain such high average flux. The first phase of the eruption (August 31, 2014 to mid-October 2014) had a discharge rate of ~350 to 100 m3/s and was typified by lava transport via open channels and the formation of four lava flows, no. 1–4,which were emplaced side by side. The eruption began on a 1.8 km long fissure, feeding partly incandescent sheets of slabby pāhoehoe up to 500 m wide. By the following day the lava transport got confined to open channels and the dominant lava morphology changed to rubbly pāhoehoe and ‘a’ā. The latter became the dominating morphology of lava flows no. 1–8. The second phase of the eruption (Mid-October to end November) had a discharge of ~100–50 m3/s. During this time the lava transport system changed, via the formation of a b1 km2 lava pond ~1 km east of the vent. The pond most likely formed in a topographical low created by a the pre-existing Holuhraun and the newHoluhraun lava flow fields. This pond became themain point of lava distribution, controlling the emplacement of subsequent flows (i.e. no. 5–8). Towards the end of this phase inflation plateaus developed in lava flowno. 1. These inflation plateaus were the surface manifestation of a growing lava tube system, which formed as lava ponded in the open lava channels creating sufficient lavastatic pressure in the fluid lava to lift the roof of the lava channels. This allowed new lava into the previously active lava channel lifting the channel roof via inflation. The final (third) phase, lasting from December to end-February 2015 had a mean discharge rate of ~50 m3/s. In this phase the lava transport was mainly ...