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Assessing long-term volcanic gas hazard through probabilistic approach: insights from case studies

Silvia Massaro1,2

  • Affiliations: 1National Institute of Geophysics and Volcanology, Bologna Branch (Italy) 2 Department of Earth and Geoenvironmental Science, University of Bari (Italy)

  • Presentation type: Talk [Invited]

  • Presentation time: Tuesday 14:15 - 14:30, Room R290

  • Programme No: 6.3.1

  • Theme 6 > Session 3

Abstract

Persistent volcanic degassing can have significant long-term impacts (years to decades) on both human health and the environment at local and regional scales. To address these risks, probabilistic volcanic hazard assessment (PVHA) of gas dispersion has recently emerged as a critical tool for risk mitigation in active volcanic areas. Standard PVHA methodologies rely on running physical models of gas dispersal that explore uncertainties in input parameters and boundary conditions, enabling robust hazard quantification. However, model validation is crucial to ensure accuracy before applying such tools in probabilistic frameworks. Uncertainties in volcanic gas hazard assessments arise from simplifications in the physical processes and assumptions in model formulations.  This contribution shows some numerical performances aimed to provide realistic long-term assessments of gas concentrations at active volcanic sites characterized by persistent passive/gravitative degassing such as La Solfatara crater (Campi Flegrei, Italy), Vulcano (Aeolian islands, Italy) Caldeiras da Ribeira Grande (São Miguel Island, Azores), Stephanos crater (Nisyros, Greece), Lake Pavin (France). Using published and original flux data, probabilistic numerical simulations were carried out using the open-source Python workflow VIGIL for parallelized probabilistic outputs. Simulations incorporate two Eulerian models (DISGAS and TWODEE-2), accounting for passive and gravity-driven gas transport, respectively. The probabilistic hazard results incorporate meteorological variability over the past 30 years, derived from Copernicus ERA5 reanalysis data. This approach provides critical insights into potential gas hazard scenarios and their implications during future periods of volcanic unrest, contributing to effective hazard preparedness and mitigation strategies.