From magmas to volcanic eruptions: dynamics and associated hazards

This project investigates eruptive products from a wide range of volcanoes to reconstruct the processes that shape magma and volcanic activity before, during, and after eruptions. Petrological and textural analyses of volcanic rocks and tephra provide clues to the physicochemical evolution of magma during storage at depth and transfer toward the surface.

Changes in pressure, temperature, and composition influence magma properties as it evolves. Crystallization can increase magma viscosity, while volatile exsolution and bubble growth affect its internal gas pressure. As bubbles connect and coalesce, permeable pathways may form, allowing gas to escape. The balance between gas pressure and magma viscosity influences magma ascent, overpressure, and fragmentation. Ultimately, these processes govern whether an eruption produces lava flows, explosive fragmentation, or a combination of eruptive styles.

The research combines in situ and remote-sensing field measurements, ground- and drone-based sampling during and after eruptions, and syn-eruptive geophysical and geochemical monitoring. The resulting observations help connect processes within the magma to eruptive dynamics and associated hazards, including lava flows, ballistic ejecta, and ash fallout. Laboratory methods include sieve analysis, pycnometry, permeability measurements, FE-SEM with TIMA, FIB, TEM, high-resolution and spectral micro-CT, XRF, and EPMA. These techniques are used to characterize grain-size distributions, particle density and porosity, vesicle and crystal size distributions (VSD and CSD), and glass, mineral, and bulk-rock compositions. XRF provides bulk-rock major-element compositions, while EPMA is used to analyze glass and mineral chemistry; imaging methods reveal particle textures and internal structures. Analysis tools using artificial intelligence are currently developed to segment and analyze volcanic plume and cloud components. Experimental approaches using 4D micro-CT are also being developed to track magma degassing and crystallization, and to investigate the formation and evolution of volcanic ash aggregates.

Together, these approaches link the petrology of volcanic rocks to the physical processes that control eruptive dynamics and volcanic hazards.