Sete Cidades Volcano, in the Azores archipelago, is located on the western side of S. Miguel Island, the largest and most populated island of the archipelago. Azores major city, with about 75.000 inhabitants, rests within a distance of about 10 km from Sete Cidades Volcano and several other small villages are situated around this volcano. About 800 people live inside the caldera. This setting determines the relevance of volcanic risk assessment in this area as a major civil protection issue.
The objective of this project is to explore new tools developed on the scope of EXPLORIS project and to address volcanic hazard and susceptibility around Sete Cidades Volcano (S. Miguel, Azores), a key issue related with pyroclastic density currents. To achieve this goal numerical simulations of the transient 3D dynamics of pyroclastic flows will be run and several eruptive conditions based on eruption scenarios drawn from Sete Cidades eruptive history will be tested.
For a scenario constrained by the eruptive activity of Sete Cidades Volcano during last 5000 years, an eruptive event similar to P11 eruption may be considered the maximum expected event for an intracaldera eruption. The main eruptive products were alternating lapilli and ash layers, deposited mainly by fallout, and minor surge deposits. Outside the caldera there is no major evidence of pyroclastic flow deposits associated with P11, nevertheless, several other recent eruptions did produce pyroclastic flow deposits and it must be considered that pyroclastic flows may be contained inside the caldera depression and, thereby, would not be exposed on the volcano flaks.
Simulation of generation and dispersal of pyroclastic flows will be performed for P11 vent conditions to assess the influence of topography and caldera shape on the spreading of pyroclastic flows. Numerical simulations will be performed using the Pyroclastic Dispersal Analysis Code (PDAC).
The numerical code PDAC was developed by INGV in cooperation with CNR and CINECA, based on previous numerical codes for the multiphase flow simulation of collapsing volcanic columns. PDAC solves the multiphase flow transport equations for density, momentum and energy of a gas-pyroclast mixture in a steady standard atmosphere.
The rendering of the simulations output data will be processed by a graphical application in development by INGV and CINECA. The application is a tool intended for basic representation of output files and geometries, advanced post-processing, integration and representation of topographic profiles and processing of large data-sets.