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Small scale caldera collapse - A numerical study on central vent caldera-foming eruptions

Pascal Aellig1, Albert de Montserrat2, Boris Kaus1

  • Affiliations: 1Institute of Geosciences, Johannes Gutenberg - University, Mainz, Germany; 2Department of Earth and Planetary Sciences, ETH Zurich, Zurich, Switzerland

  • Presentation type: Poster

  • Presentation time: Thursday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 51

  • Programme No: 3.11.11

  • Theme 3 > Session 11

Abstract

Large-scale magmatic systems are commonly associated with catastrophic caldera-forming eruptions. These events are generally linked to faults or eruption channels located at the periphery of the magma chamber, resulting in a caldera that reflects the full spatial extent of the reservoir. However, the dynamics of small to intermediate -scale magmatic systems that have also hosted caldera-forming eruptions, such as Krakatau (Indonesia) or Crater Lake (USA), are comparatively less explored. In these instances, the eruption is generally assumed to have begun from a single central vent of a volcanic edifice rather than through a ring fault system. In this study, we utilise a multi-physics numerical modelling approach to investigate the mechanics of central vent eruptions on the collapse stage. The interactions between magma dynamics, far-field tectonic stresses and non-linear visco-elasto-plastic rheologies are examined using the thermo-mechanical geodynamic code JustRelax.jl, in order to investigate the potential for roof failure above a shallow magma chamber. The models incorporate a thermally active magma chamber with variable geometries, connected to the volcanic edifice via a conduit structure. This framework allows the simulation of upward magma flow and the progressive depletion of the chamber, thereby providing insights into the processes governing central vent-driven caldera formation. Here we present a systematic parameter study on the driving forces behind this type of caldera collapse.