Abstract

What is the link between caldera collapses and large volume lava eruptions? The first detailed observations of such coupled activity are from the 2014-2015 volcano-tectonic episode in the Bardarbunga volcanic system in Iceland, which occurred during the European FUTUREVOLC volcano supersite project. Bardarbunga is a subglacial basaltic caldera volcano under the Vatnajökull ice cap above the center of the Icelandic hotspot, with an associated 150-km long fissure swarm. A major lava eruption occurred in the Holuhraun plain north of Vatnajökull (about 1.5 km3) and a gradual caldera collapse of the ice covered Bárðarbunga caldera (about 65 m), connected by a 50 km long dyke (about 0.5 km3) that formed mostly over 2-4 weeks after the onset of activity on 16 August 2014. Interaction between the pressure exerted by the subsiding reservoir roof and the physical properties of the subsurface flow path explain observed gradual, near-exponential decline of both collapse rate and the intensity of the 180-day-long eruption.

Sigmundsson, F., Hooper, A. Hreinsdottir, S., Vogfjord, K.S., Ofeigsson, B.G., Heimisson, E.R., Dumont, S., Parks, M., Spaans, K., Gudmundsson, G.B., Drouin, V., + 26 others (2015), Segmented lateral dyke growth in a rifting event at Bardarbunga volcanic system, Iceland, Nature, 517(7533), 191–195, doi:10.1038/nature14111.


Gudmundsson, M.T., Jónsdóttir, K., Hooper, A., Holohan, E. P., Halldórsson, S.A., Ófeigsson, B.G., Cesca, S.,Vogfjörd, K.S, Sigmundsson, F., Högnadóttir, Th., Einarsson, P. + 37 others (2016), Gradual caldera collapse at Bárdarbunga volcano, Iceland, regulated by lateral magma outflow, Science, 15 July 2016, vol. 353, issue 6296, aaf8988. DOI : 10.1126/science.aaf8988.