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Estimating the intensity of explosive volcanic eruptions using volcanic cloud spreading rates

Rebecca Tanner1, Dr Thomas Aubry1, Prof Matthew Watson2, Dr Samantha Engwell3, Prof Fred Prata4

  • Affiliations: 1Department of Earth and Environmental Science, University of Exeter, Penryn, UK; 2School of Earth Sciences, University of Bristol, Bristol, UK; 3British Geological Survey, Edinburgh, UK; 4AIRES Pty Ltd, Mount Eliza, VIC 3930, Australia

  • Presentation type: Talk

  • Presentation time: Thursday 08:45 - 09:00, Room R280

  • Programme No: 6.4.2

  • Theme 6 > Session 4

Abstract

The dynamical evolution of volcanic plumes has important implications for the prediction of ash cloud formation and dispersal, and its associated hazards. Volcanic ash transport and dispersion models rely on input eruption source parameters, including the eruption intensity, often termed mass eruption rate (MER). Two of the most popular methods to estimate MER are: (i) inverting from plume height using a volcanic plume model, most commonly a simple empirical relationship between MER and height; and (ii) reconstruction after the eruption from the duration and the deposit-derived total mass of tephra. Estimates of MER from these methods commonly differ by 1-2 order of magnitude, limiting our understanding of volcanic plume dynamics. Here, we expand on a third method, estimating MER from the satellite-measured growth rate of volcanic clouds, which has only been applied to a select few eruptions to date. Previous iterations of this method are also not applicable for the full range of eruption intensity and wind conditions governing volcanic cloud spreading. We will present a comparison and suggest improvements to existing methodologies and apply these methodologies to a range of plume types. By systematically comparing the spreading-derived MER estimates to those derived from plume height measurements, we provide further constraints on MER and its uncertainty. This will lead to better forecasting of ash dispersal during explosive volcanic eruptions, as well as development and improvement of existing plume models.