Superheated magma from the 2021 Tajogaite eruption on La Palma has been shown to alter eruption dynamics by dissolving the microscopic crystal seeds that normally initiate solidification. Researchers analysing samples from the event report that when magma becomes sufficiently hot, those seeds are removed, allowing molten rock to remain fluid for longer as it ascends toward the surface.
The process reduces early crystallization by eliminating nucleation points that would otherwise trigger the growth of crystals as temperature and pressure change during ascent. With fewer crystals forming at depth, the melt preserves a lower effective viscosity and can retain volatiles in a state that supports more sustained and vigorous flow. This change in physical state alters how gas and melt interact during eruption.
Observed lava fountains at Tajogaite reached notable heights during the 2021 sequence. The new findings provide a mechanistic explanation for how episodes of extreme heating can contribute to such behaviour: by prolonging fluidity and modifying ascent dynamics, superheated magma creates conditions more favourable to the generation of tall lava fountains. The study links laboratory and field observations to the eruptive features recorded during the event.
Researchers emphasise that incorporating temperature-dependent crystal dissolution into models of magma transport and eruption could improve interpretation of monitoring data and hazard assessments. The authors note that quantifying the temperature thresholds and crystal populations that permit this behaviour across different magma types will require additional sample analyses and experimental work. The results refine understanding of one pathway by which variations in magma thermal state influence eruption style.
