Figure 1 - Example of the sampled points in the MER-Hcol space considering all size classes.
Figure 2 - Example of a footprint generated for the small-scale domain in November, showing the expected maximum tephra load if an eruption occurs in the Azores.
Figure 3 - Example of a footprint generated for the large-scale domain in November, showing the expected maximum amount of tephra in the atmosphere at the lowest altitude level considered after an eruption occurs in the Azores.

Geo-INQUIRE Transnational Access Project Report: TEPHRAZOR from Simone Aguiar (IVAR, Portugal)

Geo-INQUIRE installation: PVHA - Probabilistic Volcanic Hazard Assessment (TA2-541-1/ TA2-541-2)

Project title: Long-term Probabilistic Volcanic Hazard Assessment of the North Atlantic–European Region: application to tephra hazard from the Azores

Transnational access principal investigator: Simone Aguiar (Research Institute for Volcanology and Risk Assessment (IVAR) - University of the Azores, Portugal)

Project acronym: TEPHRAZOR

Project report ID: C1-TA2-541-1-2 (1st Call)

Transnational access team: Maria Ramalho (Research Institute for Volcanology and Risk Assessment (IVAR) - University of the Azores); Adriano Pimentel (Research Institute for Volcanology and Risk Assessment (IVAR) - University of the Azores); José Pacheco (Research Institute for Volcanology and Risk Assessment (IVAR) - University of the Azores).

Collaborators: Piero Lanucara (CINECA); Beatriz Montesinos (INGV – Instituto Nazionale Geofisica e Vulcanologia, Sezione di Bologna); Chiara Saturnino (INGV – Instituto Nazionale Geofisica e Vulcanologia, Sezione di Bologna); Irene Molinari - (INGV – Instituto Nazionale Geofisica e Vulcanologia, Sezione di Bologna)

Date of visit: 3 – 28 March 2025

Geo-INQUIRE Virtual Access: in progress

Data/Products: in progress

 

Project report:

The TEPHRAZOR project aims to develop the first long-term probabilistic volcanic hazard assessment (PVHA) for tephra fallout and airborne ash generated by explosive eruptions at the central volcanoes of São Miguel Island, Azores, taking advantage of the high-performance computing (HPC) capabilities provided by the Geo-INQUIRE Transnational Access. The probabilistic approach, based on the Bayesian event tree (BET) method, will allow the generation of long-term hazard maps for different volcanic scenarios, including tephra fallout (load) and ash concentration at specific flight levels, and to evaluate the associated uncertainty.

During the project, the PI learned to implement the Fall3D dispersal model within an HPC based workflow for generating simulations designed to capture a full range of eruptive and atmospheric variability that influences tephra transport and deposition. A detailed set of eruptive scenarios were defined for VEI 3, 4, and 5 events, and eruptive parameters were sampled from probability density functions.  To account for variability in meteorological conditions, 30 years of ERA5 reanalysis data were incorporated into the simulations. For the probabilistic hazard calculations, tephra footprints are being produced for each simulation and month, considering two different computational domains: a high-resolution grid to assess tephra load and impact on São Miguel Island, and a large-scale domain to evaluate the airborne ash concentration, arrival times, and atmospheric persistence affecting Europe.

Overall, the project aims to provide the foundations for a new generation of long-term volcanic hazard assessments for the Azores, particularly for São Miguel Island, and for the North Atlantic–European airspace, offering a more robust framework than ever before.