Far-reaching volcaniclastic density current deposits as evidence of explosive marine eruptions
- Jacob A. Nash
- Isobel A. Yeo
- Michael A. Clare
- James Hunt
- Andrew B. Cundy
- Sally Watson
- Richard Wysoczanski
- Sarah Seabrook
- Kevin Mackay
- Shane J. Cronin
- Joali Paredes-Mariño
- Taaniela Kula
- Rennie Vaiomounga
- Cían McGuire
- Miros S. J. Charidemou
2026-04-30
Underwater sediment density currents triggered by marine volcanic eruptions threaten island communities and infrastructure, while their deposits provide archives of past eruptions. Despite their significance, scarce real-time density current observations and concurrent deposit samples limit our understanding of their behaviour and relationship to varying volcanic mechanisms. Using data acquired following the explosive, VEI 6, shallow-submarine eruption of Hunga Volcano in 2022, we show that syn-eruptive delivery of pyroclastic material into the ocean via low-column collapses and fountaining triggered the multidirectional dispersal of highly-concentrated underwater density currents. Rapid supply of > 6.5 km 3 of dense pyroclastic material onto the steep volcanic flanks over minutes-to-hours generated currents that maintain high density and velocity 10-100s of kilometres from the volcano. We outline diagnostic criteria to differentiate deposits of shallow-submarine generated underwater currents from other volcanic processes - enabling better reconstruction of the records of volcanic activity in marine sediments and enhancing hazard assessments in submerged volcanic settings worldwide.