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Plume dynamics and source parameters of the Veiðivötn 1477CE basaltic Plinian eruption retrieved from field work and plume modelling

Méline Payet--Clerc1 ,2, Guillaume Carazzo2, William M. Moreland3, Ármann Höskuldsson1, Thor Thordarson4,

  • Affiliations: 1Institute of Earth sciences, University of Iceland, Reykjavík, Iceland; 2Institut de Physique du Globe de Paris, Univeristé de Paris Cité, Paris, France; 3Icelandic Meteorological Office, Reykjavík, Iceland; 4Faculty of Earth sciences, University of Iceland, Reykjavík, Iceland.

  • Presentation type: Talk

  • Presentation time: Thursday 08:30 - 08:45, Room S160

  • Programme No: 3.12.1

  • Theme 3 > Session 12

Abstract

The Veiðivötn 1477 CE basaltic explosive eruption occurred along a discontinuous fissure measuring approximately 70 km in length in southern Iceland. An estimated 10 km^3 of basaltic tephra were emitted, covering an inland area of around 53,000 km^2. These tephras reached as far as Greenland and Scandinavia, indicating a powerful eruptive plume that extended high into the atmosphere, dispersing volcanic ash across extensive distances. Despite being one of Iceland's most significant historical eruptions, the Veiðivötn 1477 CE event has received limited attention. Information regarding its volume, isopachs, and petrological data remains sparse. In this study, we present new field data collected between 2023 and 2024, focusing on tephra grain size distribution (TGSD), product density, and deposit mapping. By integrating this field data with a one-dimensional physical plume model (PPM), we can estimate the critical Mass Eruption Rate (MER) prior to column collapse for various volatile contents, as well as the maximum column height. We modelled the plume for a polar atmosphere and under different complex wind profiles. Our model results suggest a MER necessary to generate a plume consistent with the field data, ranging from 10^7 to 10^8 kg/s and a maximum plume height between 15 and 25 km for volatile content of 1-2 wt%. This study provides a fresh perspective on utilizing one-dimensional models to predict critical conditions and refine essential values. Our findings also underscore the significance of gas content in sustaining a stable plume during Plinian basaltic eruptions.