Vaerewyck C. auteur aut IRD Paris R. auteur aut IRD Roche Olivier auteur aut IRD Bougouin A. auteur aut IRD text journalArticle eng text/pdf born digital access Explosive volcanic eruptions at sea or near coastlines can produce eruptive columns of hot gas and solidified magma fragments that may rise up to 50-55 km before collapsing into the water. Long overlooked, this process has recently been proposed as a potential tsunami source, notably during the January 2022 Hunga Tonga-Hunga Ha'apai eruption. It offers a new perspective on tsunami generation and may shed light on historical events such as the 1883 Krakatau eruption. Yet, the tsunamigenic potential of eruptive column collapse into the sea remains largely hypothetical and poorly constrained. In this context, we present exploratory laboratory experiments on the vertical collapse of granular material into water, systematically varying the initial granular mass, drop height, and average particle volume concentration. Our study shows that (i) vertical granular collapse into water can generate tsunamis, (ii) the amplitude of the leading (first) wave is mainly controlled by the granular mass flow rate at impact, and (iii) the wave generation process differs quantitatively, but not qualitatively, from solid-block impacts. These findings provide experimental evidence of the tsunamigenic potential of eruptive column collapse and open new avenues for understanding and modeling this source mechanism, as well as for reinterpreting tsunamis reported during past eruptions. specialized Volcanic tsunami eruptive column vertical collapse granular material TONGA PACIFIQUE SUD: HUNGA TONGA HUNGA HA APAI VOLCAN 020 066 032 064 [Early access] [20 p.] 2026 0033-4553 https://www.documentation.ird.fr/hor/fdi:010097376 10.1007/s00024-026-04016-w 0033-4553 [F B010097376] https://www.documentation.ird.fr/hor/fdi:010097376 https://www.documentation.ird.fr/intranet/publi/2026-07/010097376.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2026-07-09 2026-07-09 fdi:010097376 fre