DisEqm: quantifying disequilibrium processes in basaltic volcanism

Project overview

Basaltic volcanism is the most common form of volcanism in the solar system. On Earth, eruptions can impact global and regional climate, and threaten populations living in their shadow, through a combination of ash, gas and lava emissions. The specific risk to the UK from an Icelandic eruption is recognized as one of the four ‘highest priority risks’ in the National Risk Register of Civil Emergencies. The impact of an eruption is determined by both intensity and style, ranging from explosive and ash-rich (impacting on air-space access and climate) to effusive and gas-rich (affecting climate, public health and crops/livestock locally and distally).

Understanding these eruptive styles, and their evolution in time and space is key to forecasting the impacts of eruptions.
In order to meet this core aim, we bring together a world-leading team to perform experiments using new, ground-breaking synchroton X-ray imaging and rheometric techniques to visualise and quantify crystallisation, degassing and multiphase, HPHT (high-pressure, high-temperature) viscosity evolution, revolutionising the fields of experimental petrology and HPHT rheometry. We will perform large scale fluid dynamics simulations to inform and test the 3D numerical modelling, and we will constrain fragmentation and eruption column processes with empirical field studies.
Results will be integrated into a state-of-the-art numerical model, and applied to impact-focussed case studies for Icelandic, US and Italian basaltic eruptions. In conclusion, our project will produce a paradigm shift in our understanding of disequilibrium processes during magma ascent and our capacity for modelling basaltic eruption phenomena, creating a step-change in our ability to forecast and quantify the impacts of basaltic eruptions.

The main aim of the DisEqm project are to improve our understanding of kinetically-limited crystal growth and gas exolsution during ascent of baslatic magma. In order to acheive this aim, we have defined a series of objectives, which describe the methodologies that we will apply in order to advance our scientific understanding of baslatic volcanism and the impact of the DisEqm project

• Develop and apply 4D in-situ X-ray tomography of HPHT experiments to quantify the equlilbrium and disequilibrium crystallisation and degassing behaviour of natural basaltic melt
• Develop new HPHT apparatus for direct rheometry of basaltic melts
• Build scaled analogue models to examine multiphase fluid flow in a fissure system
• Create a tested, physically-based numerical model for disequilibrium ascent and eruption of basaltic magma, starting in 1D and extending to 3D using the OpenFOAM framework

Apply the model to examine questions regarding:

• What allows basaltic systems to produce a wide range of eruption styles and scales?
• What role do disequilibrium processes play in this diversity?
• Why do individual volcanoes exhibit a wide range of eruptive behaviour, often changing style and scale over short timescales?
• What conditions lead to highly explosive basaltic eruptions such as the subplinian Sunset Crater eruption, among others?
• How can we better interpret surface gas composition and flux measurements in terms of subsurface magma dynamics?

In collaboration with the Steering Committee, we will define future scenarios for Icelandic, Italian and continental US eruptions, and run the DisEqm model to produce eruption source parameters for each scenario

• We will encourage the adoption of models arising from DisEqm for use during volcanic crises.

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The Steering Committee has the purpose of oversight of the DisEqm project, guaranteeing that the focus remains clear on the main impact-focused goals of the project from start to finish.

It's members represent key stakeholders in European and US Volcanology.