Admissions > PhD by research > Research Projects > Stow or blow? – When magma enters the crust…

Stow or blow? – When magma enters the crust….

Supervisors: Catherine Annen, Luca Caricchi, Joachim Gottsmann, in collaboration with Thierry Menand, University Blaise Pascal, Clermont-Ferrrand

Injection of magma into the Earth’s crust either leads to the formation of a pluton or a volcanic eruption. It is of utmost importance to know if magma emplacement triggers volcanic activity as opposed to the magma chilling at depth and ultimately freezing to form a pluton. Magma may be injected into a solid host rock or an established magma reservoir and involve crustal anatexis, remelting, crystallization and/or degassing. The injection itself and subsequent physico-chemical processes are associated with pressure and volume (density) changes, which translate to ground deformation and changes in gravity at the Earth’s surface. Time-dependent gravimetric and ground deformation measurements can detect subsurface processes beneath volcanoes long before magma flow leads to earthquakes or other eruption precursors (Battaglia et al., 2008; Dzursin and Johnson, 2003), and are consequently vital components in the quantification of sub-surface processes. Unfortunately the link between these geodetic signals and underlying magmatic processes is still poorly understood.

This project aims at gaining a fundamental understanding of magma emplacement and evolution by simulating associated physical processes and evaluating their geodetic expression. Ultimately, the fundamental and outstanding questions we want to answer are:

"What is the geodetic signature of an imminent eruption?"

and

“Can we see it coming”?

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Figure 1: Thermal modeling of a growing
magma intrusion

The student will apply and partly develop thermo-mechanical models to simulate processes of magma emplacement in the crust. Magma chamber formation and evolution involves incremental intrusion with associated heat transfer [Annen et al., 2008; Annen, 2009]. Thus models are needed that integrate the thermal and mechanical processes.

The goal of these simulations is to identify critical parameters that enable us to distinguish between magma ponding and magma chamber priming based on their respective geodetic signature.




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Figure 2: Ground deformation revealed
satellite based interferometric data
(Prittchard and Simon, 2002)

These simulations will be based on current models of pluton formation and reservoir ripening [e.g. Paterson and Folwer, 1993; Jellinek and de Paolo, 2003; Menand, 2008], and their results compared with data from areas undergoing crustal uplift. A pertinent example is the large ground deformation anomaly in the Altiplano-Puna volcanic area in southern Bolivia, which is interpreted to result from an active magmatic intrusion in the Andes [Prichard and Simons, 2002, Sparks et al., 2008].

There has been almost two decades of uplift at an average maximum rate of 1-2 cm/year recorded by InSAR over an area about 70 km across around Uturuncu volcano. The School is involved in a major externally-funded research program on Uturuncu and results will become available for the project.




The project suits a numerate student with a drive to integrate computational Earth Sciences models with field investigations. Experience with the application of mathematical models to geological processes is of advantage but not essential.


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Last updated: 8/11/11