Pinpointing the volatile driver for sudden large-scale volcanic eruptions

Sudden and violent volcanic eruptions, such as the 15th January 2022 Hunga explosion in Tonga are rare and catastrophic events. This large event was unexpected from a volcano that in the recent past had only produced mild, small-scale eruptions. The 15th January event followed a month-long period of low-magnitude activity with the climactic explosion not conforming to standard models of gas-driven explosive volcanism. We have obtained a unique collection of samples from the 2021/2022 eruption, as well as historic (2009, 2015) and pre-historic eruption deposits at Hunga volcano that are now largely destroyed. This provides a one-off research opportunity to understand one of the most enigmatic eruptions of modern volcanology. We will quantify the role of magmatic gases and the compositional heterogeneities of melt and crystals to reconstruct the pre-eruptive plumbing system geometry. Rates and drivers of natural magmatic processes will be simulated with novel experiments of crystallization, magma rise and melt/gas separation. We will model the timescales of crystal growth in changing magmatic environments and hence reconstruct the sequence of events leading up to the catastrophic 15th January explosion. Our quantification of the spatial dynamics and timescales of magmatic processes will inform new models of sudden large volcanic explosions.