The tight link between magma plumbing system and volcano monitoring: a contribution from the multidisciplinary petrological and geochemical framework (MPGF)

Forecasting sismo-volcanic events and their evolution in time and space requires a detailed understanding of magma plumbing systems in terms of their geometry, connectivity, and physico-chemical properties.

The MPGF’s multidisciplinary approach, developed over the last decades on several active volcanoes, integrates petrochemical reconstruction of the plumbing system with detailed geochemical characterization and high-frequency monitoring of gas emissions. This framework allows us to constrain magma evolution and dynamics within a volcano’s plumbing system over a wide range of pressures, temperatures, and compositions, as well as across various timescales and eruption frequencies.

Here, we review key insights gained from active volcanic systems in the Indian Ocean (La Réunion, Mayotte, and the Comoros) that have formed in different geodynamic settings (intraplate and plate boundary) and exhibit highly contrasting eruption rates, volumes, and dynamics. Among the most significant findings, we highlight:
i) The role of lateral shifts in deep magma ascent paths relative to eruptive sites, and
ii) The coexistence of both evolved (phonolite to trachyte) and mafic (basalt to basanite) melts over a broad depth range, from the mantle to the crust.

Effective long-term monitoring is achieved by focusing on the deepest parts of the plumbing system (often located on the volcano flanks) which enables the identification and tracking of new magma inputs that may lead to lateral magma drainage at shallower levels. We emphasize the importance of detecting deep silicic and variably degassed melts—sometimes already present in the mantle and near the Moho—alongside mafic, volatile-rich melts. This approach provides a robust foundation for geochemical and petrological monitoring and for sound integration between geochemical and geophysical datasets.