Explosive volcanic eruptions are sudden and violent events in a volcano’s life cycle. Despite significant advancements over the past decades, they remain largely unpredictable regarding onset, duration and style. Amongst the diverse volcanic hazards, pyroclastic density currents (PDCs) stand out as the most fatal.

PDCs are high-energy mixtures of hot gas and particles that travel down a volcano’s flanks, driven by a combination of initial particle momentum and gravity, and influenced by local topography and vegetation. While their internal dynamics remain poorly constrained, deposit analyses suggest large variability in particle concentration, velocity and temperature. As sedimentary features vary quickly over close range, all those factors are likely highly dynamic in space and time. Although commonly associated with major explosive eruptions, PDCs can also be generated by the collapse of lava domes, flow fronts, or hot deposits during moderately explosive or even effusive activity. The impacts of such events can rival or exceed those of more classically explosive eruptions. Recent advances in numerical modelling have improved our ability to simulate key aspects of PDC behaviour, from generation to deposition, significantly contributing to our understanding of their dynamics.

This session aims to bring together researchers working on all facets of PDCs, from field studies and laboratory experiments to remote sensing and numerical modelling. By fostering interdisciplinary dialogue, we aim to advance understanding, improve hazard assessment and reduce risk in future eruptions.