Long-term probabilistic hazard assessment posed by gas dispersion at Vulcano island (Aeolian archipelago, Italy)

Persistently active volcanoes emit gas continuously and may present a long-term hazard depending upon the gas specie, concentration levels and exposure time.

Following the last gas crisis occurred at Vulcano island (Aeolian archipelago, Italy) during 2021-2022, the surveillance activities carried out by the personnel of the Istituto Nazionale di Geofisica and Vulcanologia of Palermo Branch and the Etnean Observatory, let us to investigate the state of the island's hazard concerning volcanic gases by considering two degassing scenarios for CO₂ and SO₂ dispersion (background and unrest). To do this, we used the recently released version of VIGIL workflow (1.3.8) able to run automatically passive or gravity-driven gas dispersion simulations using DISGAS (2.6.0) and TWODEE-2 (2.6.0) models, respectively. Both models are interfaced with DIAGNO simulator (1.5.0) that require daily meteorological data.

Our results are based on 1000 simulations using averaged wind profiles from the ECMWF ERA5 database which constitute a representative sample of meteorological variability over the past 30 years (1993-2023). Long-term hazard maps are related to the probabilities of exceedance (PE) at 5% and 10% of the simulated CO₂ and SO₂ concentration at a height of 1.5 m above the ground (referring to the average height of a person). Persistence maps are built considering different thresholds for human exposure in accordance with the regulations of the European Union and the World Health Organization. Additionally, we present ongoing efforts to address current limitations in the VIGIL workflow, including improvements in handling source uncertainty (location and intensity), a more user-friendly interface, and the integration of a new wind simulator.