The East African Institute for Fundamental Research (EAIFR) wishes to invite you to our next GEO@EAIFR webinar. This seminar will take place on October 15, 2025 and will be broadcast live on ZOOM. It will also be recorded and later posted on the ICTP-EAIFR YouTube channel, where one can find all previous  GEO@EAIFR webinar recordings. Below are the details:

Speaker: Dr. Tomaso Esposti Ongaro, Director of the Pisa Department of the Istituto Nazionale di Geofisica e Vulcanologia - INGV – Italy

Title: Multiphase Flow Modeling in Volcanic Eruptions: From Magma Dynamics to Pyroclastic Transport

When: October 15, 2025 at 4:00 pm (Kigali time).

Register in advance for this meeting by clicking here.

All are very welcome.

Abstract: 

Multiphase flows describe the motion of non-homogeneous mixtures of gas, liquid, and solid particles, encompassing a broad spectrum of dynamical regimes. These flows are ubiquitous in volcanology, as their dynamics govern the entire process of magma differentiation, migration, and fragmentation. In explosive eruptions, multiphase dynamics characterize the generation, ejection, transport, and sedimentation of granular volcanic products, known as pyroclasts.
This seminar will introduce the continuous mechanics (fluid) modeling of volcanic polydisperse gas-particle flows. We will describe the granular stress tensor across three key flow regimes: the concentrated (particle volume fraction  >  0.1), collisional (0.001 <  <  0.1), and kinetic ( <  0.001) regimes. We will also detail the complex interactions between the granular and the interstitial fluids. We will demonstrate that a complete fluid dynamic modeling of explosive eruptions, which must encompass all dynamic regimes, necessitates High-Performance Simulation capabilities.
Finally, we will present computational applications, specifically focusing on the modeling of phreatic explosions at Vulcano, Italy, and pyroclastic avalanches at Stromboli, Italy.

Biography:

Dr. Tomaso Esposti Ongaro (Director of the Pisa Dept. of Istituto Nazionale di Geofisica e Vulcanologia - INGV – Italy) got a degree in Physics at the University of Pisa, and a PhD in Modeling for environmental protection at the University of Bologna (Italy). Expert in geophysical multiphase flows and numerical modelling of volcanic processes, he is among the worldwide leaders in the application of High Performance Computing to volcanology. He pioneered the three-dimensional, multiphase (gas-particle) flow simulation of explosive volcanic eruptions, applied to European and worldwide volcanoes: Vesuvio and Campi Flegrei (Italy), Soufrière Hills (Montserrat, UK), La Soufrière (Guadeloupe, lesser Antilles, France), Mount St. Helens (USA), Vulcano (Aeolian archipelago, Italy).
The scientific and technological developments he led found applications in several projects funded by EU, by the Italian Ministry of Research, and by the Italian Civil Protection for assessing direct (volcanic plumes, pyroclastic flows) and indirect (landslides, tsunami) hazards associated with explosive volcanic eruptions, before and during volcanic crises.
For his commitment in the development and application of numerical models to the assessment of volcanic hazards, he has been awarded the IAVCEI (International Association of Volcanology and Chemistry of the Earth Interior) Wager medal.