Thermal History and Magma Explosivity

Researchers from the University of Manchester have identified that the thermal history of magma, specifically a process called superheating, is a critical factor in determining whether a volcanic eruption becomes explosive or remains effusive. By heating magma beyond the point where crystals can form, the material remains fluid for significantly longer periods, which influences its ascent speed and gas release dynamics. The study, published on June 8, 2026, in Nature Communications, challenges traditional volcanic hazard models that primarily focus on chemical composition and pressure. The authors argue that pre-eruptive thermal history and crystallization kinetics are essential variables for accurately forecasting eruption styles and improving volcanic hazard assessments. Using advanced synchrotron X-ray microtomography and internally heated pressure vessels, the team observed that superheated magma delayed crystal nucleation for over eight hours, compared to just 20 minutes for non-superheated samples. This delay allows magma to rise rapidly without the viscosity increase typically caused by crystal growth, facilitating intense lava fountaining. These findings provide a new framework for interpreting volcanic monitoring data. By incorporating these crystallization delays into predictive models, scientists can better anticipate the transition between gentle lava flows and explosive eruptions, ultimately enhancing safety protocols for populations living near active volcanic regions.