Submarine Volcanic Eruption Dynamics

Submarine volcanic eruptions account for the majority of volcanic activity on Earth, yet their dynamics remain less familiar than those of subaerial counterparts. High hydrostatic pressure at depth alters bubble nucleation and growth, suppressing explosive fragmentation and favouring effusive styles or non-explosive quench fragmentation. Nevertheless, in shallower settings, rapid decompression can generate vigorous eruption columns, pyroclastic density currents along the seafloor and vast pumice rafts at the surface. Interaction between hot magma and seawater drives thermal erosion, brecciation and steam-driven explosions, while constrained eruption columns can produce co-genetic vapour plumes and floating clast accumulations. Collapse of seafloor calderas and sector failures may trigger submarine landslides and tsunamis, posing hazards to coastal communities, benthic ecosystems and subsea infrastructure such as cables and pipelines. Advances in remote sensing, in-situ monitoring and numerical modelling are now revealing the interplay between magma properties, eruption depth, ambient currents and seafloor topography that controls eruption style, dispersal of tephra and long-term ecological impacts.

Research from Nature Portfolio

Recent field surveys and multitemporal mapping of a major shallow submarine eruption documented the removal of nearly ten cubic kilometres of seafloor material, redeposited by long-runout density currents that reshaped the seabed and damaged over 100 km of communication cables. These studies revealed that benthic ecosystems survived only in topographic refugia, underscoring how seafloor morphology governs ecological resilience and recovery.

Analysis of a deep submarine silicic eruption demonstrated how a single day of magma discharge generated a kilometre-scale pumice raft, mapped by satellite imagery and reproduced by ocean-current simulations. This work established real-time forecasting of raft dispersal routes and shed light on the fate of floating clasts, providing a framework to predict the distribution of pumice and associated biological hitchhikers in both modern and prehistoric contexts.

Submarine Volcanic Eruption Dynamics publication trend

The graph below shows the total number of articles in submarine volcanic eruption dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Volcaniclastic density current: A gravity-driven flow of sediment and volcanic fragments along the seafloor, generated by collapse of eruption columns or pyroclastic flows.

Pumice raft: A floating aggregation of low-density pumice clasts formed when explosive or quench fragmentation ejects buoyant fragments onto the ocean surface.

Vertical gravity gradient (VGG): The rate of change of gravitational acceleration with depth, used to image subsurface density anomalies such as magma reservoirs.

Ambient seismic noise: Background ground motions recorded by seismometers, which can be cross-correlated to infer temporal changes in seismic velocity within the crust.

Caldera: A large, often circular depression formed by collapse of the roof of a magma chamber following rapid evacuation of magma during an eruption.

References

1. Volcaniclastic density currents explain widespread and diverse seafloor impacts of the 2022 Hunga Volcano eruption. Nature Communications (2023).
2. Detectability of Seamount Eruptions Through a Quantum Technology Gravity Mission MOCAST+: Hunga Tonga, Fani Maoré and Other Smaller Eruptions. Surveys in Geophysics (2024).
3. Relative Seismic Velocity Variations at Axial Seamount Observed With Ambient Seismic Noise Capture Transition Point in Volcanic Inflation. Geophysical Research Letters (2024).
4. Simultaneous creation of a large vapor plume and pumice raft by the 2021 Fukutoku-Oka-no-Ba shallow submarine eruption. Earth and Planetary Science Letters (2023).
5. On the fate of pumice rafts formed during the 2012 Havre submarine eruption. Nature Communications (2014).
6. Why Deep-Water Eruptions Are So Different From Subaerial Eruptions. Frontiers in Earth Science (2018).