Monitoring magma rheology-seismicity feedbacks during volcanic eruptions


  • Supervisors: Prof. Yan Lavallée, University of Liverpool
    Dr. Silvio De Angelis, University of Liverpool


  • External Supervisors: Dr. Paolo Papale, INGV-Pisa, Italy
    Prof. Chris Bean, Irish Centre for Research in Applied Geosciences
  • Contact:

    Prof. Yan Lavallée, University of Liverpool, ylava@liv.ac.uk

  • CASE Partner:

Application deadline: 10 January 2020

Introduction:

Volcanic eruptions are associated with a range of geophysical signals, including ground deformation and seismicity (Bean et al., 2014; Chouet and Matoza, 2013). These signals are triggered by the stress exerted from magma and volatiles forcing their way through the volcanic edifice. The type of signals varies widely and as a consequence, the origin of the signals remains enigmatic. Furthermore, in the course an eruption, the signals vary in time, which reflect the evolution of the rheological state of magma that degasses, crystallises and shears during ascent in volcanic conduits (Papale, 1999); Yet, the links between seismicity and rheology elude us. 

The rheology of magma has been the subject of extensive studies but key questions remain to complete the full description of magma during ascent in a conduit (Lavallée et al., 2007). Importantly, the concept of the glass transition has been invoked to distinguish between the ductile regime in which magma flows and the brittle regime, which result in the rupture of magma (Dingwell, 1996; Lavallée et al., 2008). The brittle regime has commonly been ascribed to explain seismicity associated with magma ascent (Figure 1), but other sources of ductile behaviour have also been alluded to, although not tested. 

Project Summary:

Here, we propose an exciting new project aiming to combine laboratory testing, geophysical monitoring and analysis of volcano seismicity to study the links between seismicity and the state of magma during ascent and eruption. 

The study will focus on different volcanic systems such as Mount Etna (Italy), Volcán de Colima (Mexico), for which we have a basic understanding of the magma rheology and geophysical data to develop our model. In the laboratory, targeted experiments will be conducted using novel experimental facility in the Volcanology laboratory at the University of Liverpool. These will aim to widen the range of pressure-temperature-strain rate conditions in our models. 

In addition, a volcano observatory will be set up, and a monitoring campaign will be undertaken to describe the signals of volcanic activity at a volcano (to be determined based on activity level at the time of the project). This proximal investigation will be used to increase the clarity of proximal signals related to magma ascent. 

The successful candidate will enjoy working in a dynamic, international research team aiming to understand the link between rheology and seismicity. 

We encourage applications from students holding a first-class degree in Geology or Geophysics, with aptitudes in computation (a knowledge of MatLab and or Python would be advantageous) and a keen interest in learning to employ laboratory and field techniques. This multidisciplinary work will provide the selected candidate with a strong and varied set of skills to undertake a wide range of frontier research following their doctoral study. 

References:

Bean, C. J., De Barros, L., Lokmer, I., Metaxian, J.-P., O'Brien, G., and Murphy, S., 2014, Long-period seismicity in the shallow volcanic edifice formed from slow-rupture earthquakes: Nature Geosci, v. 7, no. 1, p. 71-75. 

Chouet, B. A., and Matoza, R. S., 2013, A multi-decadal view of seismic methods for detecting precursors of magma movement and eruption: Journal of Volcanology and Geothermal Research, v. 252, p. 108-175. 

Dingwell, D. B., 1996, Volcanic dilemma: flow or blow?: Science, v. 273, no. 5278, p. 1054-1055.

Lavallée, Y., Hess, K.-U., Cordonnier, B., and Dingwell, D. B., 2007, Non-Newtonian rheological law for highly crystalline dome lavas: Geology, v. 35, no. 9, p. 843-846. 

Lavallée, Y., Meredith, P. G., Dingwell, D. B., Hess, K. U., Wassermann, J., Cordonnier, B., Gerik, A., and Kruhl, J. H., 2008, Seismogenic lavas and explosive eruption forecasting: Nature, v. 453, no. 7194, p. 507-510. 

Papale, P., 1999, Strain-induced magma fragmentation in explosive eruptions: Nature, v. 397, no. 6718, p. 425-428.

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