Volcanology

Volcanology examines the origin, ascent and eruption of magma, the resulting landforms and the deposits they produce. Volcanoes arise where melt generated in the mantle or lower crust intrudes through fractures and storage zones, feeding surface eruptions that range from gentle lava outpourings to catastrophic explosive events. The style, scale and hazards of an eruption depend on magma composition, volatile content, temperature and regional stress fields. Mafic magmas tend to form fluid lava flows and scoria cones, whereas silicic melts often drive high-column explosions, ignimbrite sheets and caldera collapse. Volcanic heat and gas emissions interact with climate, glacial systems and hydrothermal circulation, creating feedbacks that extend beyond volcanic terrain. Ancient volcanic successions preserve facies that record eruption dynamics, allowing reconstruction of past behaviours. Modern monitoring and modelling combine seismology, geodesy, petrology and geochemistry to improve eruption forecasting, hazard assessment and resource exploration.

Research from Nature Portfolio

Deformation and seismicity at Fagradalsfjall, Iceland, defied typical precursory patterns. In the months before the 2021 eruption, a 9 km-long magma-filled dyke slowly emplaced and released tectonic stress, after which both ground displacement and earthquake rates declined days before vent opening. This finding underscores the need to consider interactions between crustal rheology and regional stress release when interpreting unrest signals.

At Nyiragongo, an open-vent volcano in the Democratic Republic of Congo, a flank eruption in May 2021 began without detectable precursors. Evidence indicates that edifice rupture triggered southward magma-rich dyke intrusion at very shallow depths beneath populated areas. This reversed sequence highlights the challenge of forecasting eruptions at volcanoes with persistent summit lakes or open conduits.

In central Iceland, aeromagnetic mapping revealed buried faults beneath the Holuhraun fissure field. A previously unrecognised east-northeast–trending fault coincides with vents of the 1797 and 2014–15 eruptions, demonstrating how ancient structures can steer dyke propagation, localise eruption loci and shape lava-flow paths.

Research from all publishers

High-resolution satellite observations of the 2021 Fukutoku-Oka-no-Ba eruption in the Izu-Bonin arc captured the near-synchronous formation of a 16 km-high vapour plume and a 0.1 km³ pumice raft. Analysis of thermal-infrared and optical imagery showed that tephra jets and near-vent fallout drove raft accumulation, refining our understanding of plume–raft linkage in shallow submarine eruptions.

Ambient seismic noise analysis at the Axial Seamount mid-ocean ridge tracked seven years of relative shear-wave velocity changes in the upper kilometre of crust. Declining velocities during rapid inflation and brief increases during deflation events revealed subtle subsurface responses to magma movement, offering a non-invasive window into pre-eruptive processes beneath submarine volcanoes.

Laboratory studies of silicate melts under high hydrostatic pressure demonstrate that at depths greater than ~500 m water inhibits bubble expansion, suppressing explosive fragmentation. Under these conditions, quench fragmentation produces hyaloclastite breccias, while non-explosive effusive styles prevail, explaining fundamental differences between deep-water and subaerial eruptions.

Volcanology publication trend

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

Technical terms

Dike: A near-vertical, tabular magma intrusion that cuts across host-rock layers and commonly feeds surface eruptions.

Caldera: A large, often circular depression formed by catastrophic collapse of the ground above an emptied magma chamber.

Pyroclastic density current: A ground-hugging, turbulent flow of hot gas and volcanic particles generated by explosive eruptions or collapsing eruption columns.

Pumice raft: A floating accumulation of low-density pumice clasts produced by explosive or quench fragmentation in shallow submarine eruptions.

Magmatic overpressure: The excess pressure in a magma chamber or conduit above lithostatic load, driving dyke opening and eruption intensity.

Hydrovolcanism: Explosive interaction between magma and external water (groundwater, ice or seawater), producing characteristic deposits such as hyaloclastites.

References

1. Introductory Concepts.
2. Deformation and seismicity decline before the 2021 Fagradalsfjall eruption. Nature (2022).
3. Precursor-free eruption triggered by edifice rupture at Nyiragongo volcano. Nature (2022).
4. Pre-existing structural control on the recent Holuhraun eruptions along the Bárðarbunga spreading center, Iceland. Scientific Reports (2024).
5. 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).
6. Relative Seismic Velocity Variations at Axial Seamount Observed With Ambient Seismic Noise Capture Transition Point in Volcanic Inflation. Geophysical Research Letters (2024).
7. Why Deep-Water Eruptions Are So Different From Subaerial Eruptions. Frontiers in Earth Science (2018).