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

Periodic Reporting for period 2 - DYNAVOLC (Transitions in Rheology and Volatile Dynamics of Magmas: Mapping the Window to Explosive Volcanism)

Reporting period: 2020-04-01 to 2021-03-31

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.
Project tasks:
Work in the outgoing phase focused heavily on WP 1 and WP2. WP2 initiated early in 2019 with the first section (crystallization experiments) of task 2.1 being completed in summer 2019 and the first section of task 2.2 completed in May January 2020. The second section of tasks 2.1 and 2.2 (vesiculation experiments) were halted due to the global pandemic but preliminary results were presented at the Goldschmidt conference in late June 2020. Tasks 3.1 – 3.3 of WP3 were delayed due to the global pandemic but alternative methods and strategies have been developed. Task 3.3 is substituted by a different experimental technique (optical dilatometry) that allows for investigation of the process dynamics in 2D plus time rather than in 3D plus time (as intended by synchrotron tomography) but preliminary results are promising. Milestones M1, M2 and M4 were achieved. Milestone M3 stands shortly before completion but could not be reached due to COVID related closures of the laboratory and early termination of the project to facilitate the transition to a tenure track position.

Publications:
Beyond the immediate project tasks outlined above, time was allotted for publication of research results that are both directly and indirectly related to the MC action. Directly related publications include several of those proposed in the grant agreement, whereas indirectly related ones result from collaborative projects inspired by the work performed over the course of the action. In total to date, this MC action supported nine articles in peer reviewed journals and a number of presentations at international conferences, details on this can be found in the publications section.

Career development:
The career development plan that was set up early on in the project in collaboration with both supervisors was put in action. Active engagement in conference organization and networking events as well as strategic application to suitable faculty positions opening across the globe have resulted in securing a tenure track position to which I will transition position following termination of this project.

Public Engagement:
The project was featured in an article in the EU Horizon magazine, where I was interviewed regarding the project goals and strategies. The article can be found here: https://horizon-magazine.eu/article/age-and-foaming-how-predict-when-volcano-will-erupt.html
The project website (http://dynavolc.wordpress.com) and twitter account (@dynavolc) have been used to provide continuous updates on the project. They are frequented / followed by both the scientific community as well as the general public and journalists.
Progress beyond the state of the art:
The research results generated in the project and disseminated in the publications named above have expanded the compositional space of available rheological data under disequilibrium conditions. A rheological model specific to the Phlegrean volcanic district was derived and published in Frontiers in Earth Sciences 2020. Additionally, a new concept of deriving crystallization kinetics of natural silicate melts from the rheological measurements was developed and applied to these data (Kolzenburg et al., 2020). This is a significant advancement of the start of the art that enables comparative analyses of crystallization kinetics of experiments performed under deformation, something that was not done prior.

The experimental campaign on the vesiculation kinetics of silicate melts that was planned for and initiated during WP2 and WP3 has resulted in a novel experimental approach that was developed as an adaptation to the restrictions imposed by the global pandemic. The goal of this research is to address the mismatch between rheological measurement of bubble bearing silicate melts vs. bubble bearing analogue materials, a gap in knowledge that has existed for several decades.

Potential impacts:
The expected impact of the research performed during this project on my research field is large, in that it may be able to address a discrepancy in rheological measurements of different materials that has been unresolved for decades.
Additionally, it is expected that the rheological model for the Phlegrean volcanic district, developed and published during the outgoing phase, will start to be employed by the numerical modeling community in order to produce more accurate models of lava flow hazard in the greater Neapolitan area (the region of highest volcanic risk in Europe).
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