title: Gradual caldera collapse at Bárdarbunga volcano, Iceland, regulated by lateral magma outflow.
abstract: Large volcanic eruptions on Earth commonly occur with a collapse of the roof of a crustal magma reservoir, forming a caldera. Only a few such collapses occur per century, and the lack of detailed observations has obscured insight into the mechanical interplay between collapse and eruption. We use multiparameter geophysical and geochemical data to show that the 110-square-kilometer and 65-meter-deep collapse of Bárdarbunga caldera in 2014-2015 was initiated through withdrawal of magma, and lateral migration through a 48-kilometers-long dike, from a 12-kilometers deep reservoir. Interaction between the pressure exerted by the subsiding reservoir roof and the physical properties of the subsurface flow path explain the gradual, near-exponential decline of both collapse rate and the intensity of the 180-day-long eruption.
authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland. mtg@hi.is.
authors.forename: Magnús T
authors.initials: MT
authors.lastname: Gudmundsson
authors.affiliation: Icelandic Meteorological Office, IS-150 Reykjavík, Iceland.
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authors.lastname: Jónsdóttir
authors.affiliation: Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET), School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
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authors.affiliation: GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany. UCD School of Earth Sciences, University College Dublin, Ireland.
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authors.initials: EP
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Icelandic Meteorological Office, IS-150 Reykjavík, Iceland.
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authors.affiliation: GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany.
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authors.affiliation: Icelandic Meteorological Office, IS-150 Reykjavík, Iceland.
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authors.initials: KS
authors.lastname: Vogfjörd
authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland. Laboratoire Magmas et Volcans, CNRS-Université Blaise Pascal-IRD, 63038 Clermont-Ferrand, France.
authors.forename: Olgeir
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Faculty of Industrial and Mechanical Engineering and Computer Science, University of Iceland, Hjarðarhagi 2-6, 107 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET), School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany.
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authors.affiliation: GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.initials: GH
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authors.affiliation: GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany.
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authors.affiliation: Icelandic Meteorological Office, IS-150 Reykjavík, Iceland.
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authors.affiliation: Icelandic Meteorological Office, IS-150 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.initials: JM
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authors.affiliation: Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET), School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Karsten
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Icelandic Meteorological Office, IS-150 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland. Icelandic Meteorological Office, IS-150 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Nordvulk, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland.
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authors.affiliation: Icelandic Meteorological Office, IS-150 Reykjavík, Iceland.
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