DYNAVOLC · Transitions in Rheology and Volatile Dynamics of Magmas: Mapping the Window to Explosive Volcanism

Transitions in Rheology and Volatile Dynamics of Magmas: Mapping the Window to Explosive Volcanism

Volcanic eruptions are amongst the most spectacular and catastrophic geologic phenomena. Their impact on society and the environment spans from the destruction of infrastructure to sudden alterations of global climate, affecting social- and food-security. The growing number of inhabitants, tourists, and economic activities near volcanoes, require adequate volcanic hazard-assessment and -mitigation plans to guide decision-making in the case of volcanic unrest. The importance of, and necessity to address volcanic hazards has been recognized by the European Commission, and is manifested in the recent EC working document “Overview of Natural and Man-made Disaster Risks the European Union may face” of May23rd 2017. It highlights the need to support the improvement of European capacities to assess natural hazards as a first step towards developing disaster prevention and emergency plans. To date, accurate forecasting of volcanic behaviour is still hampered by a lack of understanding of the magmas transport properties, which predictive computer models rely on. Large volcanic eruptions are often triggered by intrusion of hot primitive (basaltic) magma into an evolved (dacite to rhyolite) magma-chamber or -mush zone. Both magmas undergo changes of state during this interaction. Variations in pressure (P) and temperature (T) result in the exsolution of volatiles (creating foam) and crystallization of minerals (creating solid particles) from the silicate melt. The resulting, non-linear, changes in the magmas transport properties alter how the magma accommodates deformation during ascent. Transport from the magma storage-chamber to the surface, therefore, represents a complex, disequilibrium phenomenon where the process-guiding material properties (dominantly viscosity) constantly evolve. This makes it one of the most interesting challenges at the interface between geo- and material-sciences. Glass-foams and glass-ceramics (partially crystallized glasses) also find a range of applications in industry like for example telescope mirrors, high-temperature-seals and insulations. Manufacturing of industrial grade glass ceramics and foam glasses requires detailed knowledge of the phase dynamics during production (the molten state). Developing an in-depth understanding of the rheological evolution of silicate melts, necessary to advance both the prediction of natural hazards and the development of industrial production processes, requires physical characterization of the melts viscosity. This project aims to systematically map the two most significant change zones in magma rheology: 1) solidification through crystallization and 2) fluidization through vesiculation to provide the missing input parameters for accurate predictive modelling of volcanic eruptions.

Data: CORDIS, © European Union