This page details some of my past research projects. If you’re interested to find out more then check out the associated publication(s) or contact me. If you have ideas and/or would like to collaborate on these projects please also get in touch (they’re all fantastic projects I would happily resurrect!).
Flank stability and deformation at Tungurahua volcano, Ecuador
Tungurahua is a steep stratovolcano in Ecuador, South America, that has been in a sequence of eruptive activity since 1999. This volcano has a history of catastrophic flank collapse, the latest of which destroyed the west flank 3000 years ago. Volcanic unrest in 2015 included significant rapid surface deformation restricted to the same west flank. This project aimed to link these two phenomena using remote sensing, field work and numerical modelling, to establish any potential relationships and develop a hazard assessment. It was conducted in collaboration with the University of Bristol, Instituto Geofísico in Ecuador, and the NERC Centre for Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET). Results found that the deformation was likely being driven by shallow magma storage beneath the west flank that could potentially promote future flank instability.
Paper (Open-access): Hickey, J., Lloyd, R., Biggs, J., Arnold, D., Mothes, P. & Muller, C. (2020) Rapid localized flank inflation and implications for potential slope instability at Tungurahua volcano, Ecuador, Earth and Planetary Science Letters, 534, 116104.
My postdoctoral research was funded by the STREVA and COMET projects. STREVA was an inter-disciplinary project working to increase the resilience of local communities to volcanic activity. COMET is an integrated Earth observation working group aiming to significantly improve the understanding of tectonic and volcanic processes and the hazards they present. My work also came under the CEOS volcanic pilot program which focused on Latin America to highlight the applicability of Earth observation (satellite) data in monitoring volcanic regions.
The operational and National Capability responsibilities of my postdoc role extended to processing InSAR data and monitoring any ongoing or new volcanic deformation episodes. This predominantly applied to Latin American countries. Results were communicated to local volcano observatories and the British government (through the British Geological Survey). The majority of the data feeding these efforts were acquired by the European Space Agency (ESA) Sentinel-1 satellite, which captures images of the majority of the world’s volcanoes with 12 day repeat intervals.
Volcano Deformation Database
Another component of this role was the initial development of a global volcano deformation database, hosted online. The site and project is still in progress. The end goal is to have a two-stage entry for every volcano. The first will outline any archived data about previous deformation studies and interpretations. The second will use ESA Sentinel-1 data to provide near-real-time interferograms that show any potential deformation. To assist with this the COMET project has developed an automated InSAR processing facility.
Paper (Open-access): Ebmeier, S. K., Andrews, B., Araya, M. C., Arnold, D., Biggs, J., Cooper, C., Cottrell, E. Furtney, M., Hickey, J., Jay, J., Lloyd, R., Parker, A., Pritchard, M., Robertson, E., Venzke, E., Williamson, J. (2018) Synthesis of global satellite observations of magmatic and volcanic deformation: implications for volcano monitoring & the lateral extent of magmatic domains, Journal of Applied Volcanology, 7, 2.
InSAR and Volcano Deformation Research
A particular focus of my InSAR postdoc research was Tungurahua volcano in Ecuador. This volcano has a history of localised inflation on its west flank, as well as destructive sector collapses, as detailed above and now published in EPSL.
My PhD (and a subsequent short-term postdoctoral position) was funded by the VUELCO project, whose main aim was to improve the understanding of the origin, nature and significance of volcanic unrest. This should lead to enhanced monitoring and better interpretation of geophysical and geochemical signals, to enable more reliable identification of eruption precursors. Such information is essential for decision makers and civil authorities during volcanic crises to allow for improved eruption forecasting, risk reduction and hazard management.
Modelling Volcanic Deformation
The specific focus of my work was examining the mechanical processes that cause and contribute to volcanic deformation during unrest periods. I developed and tested numerical models that incorporate more subsurface complexities than the typical analytical models which are often used (e.g., the Mogi model). This allowed me to analyse the effects of:
- Crustal layering
- Inelastic rheology
- Gravitational loading
- Coupled heat-transfer
- Temperature-dependent rheology
- Coupled fluid-flow
- Surface loading
Paper (Open-access): Hickey, J., & Gottsmann, J. (2014) Benchmarking and developing numerical Finite Element models of volcanic deformation. Journal of Volcanology and Geothermal Research, 280, 126–130.
Book chapter (Open-access): Hickey, J.,Gottsmann, J., Mothes, P., Odbert, H., Prutkin, I., & Vajda, P. (2017) The ups and downs of volcanic unrest: insights from integrated geodesy and numerical modelling. In: Advances in Volcanology. Springer, Berlin, Heidelberg.
To assess the importance of these various features I applied the models to three case-study volcanoes.
This study focused on the driving mechanism behind a 70 km wide region of ground uplift centred on Uturuncu volcano, in the Altiplano-Puna region of southern Bolivia. It was carried out as a joint part of the PLUTONS project. I conducted a series of forward models using finite element analysis to test for first-order parameters to constrain a viable model for the observed maximum line of sight uplift rate of 1–2 cm/yr between 1992 and 2006. The preferred model suggests that pressurisation of a magma source extending upward from the Altiplano-Puna magma body (like a magmatic diapir) caused the observed surface uplift.
Paper: Hickey, J., Gottsmann, J., & del Potro, R. (2013) The large-scale surface uplift in the Altiplano-Puna region of Bolivia: A parametric study of source characteristics and crustal rheology using finite element analysis. Geochemistry, Geophysics, Geosystems, 14(3), 540–555.
Paper (Open access): Muir, D., Blundy, J., Rust, A., & Hickey, J. (2014) Experimental constraints on dacite pre-eruptive magma storage conditions beneath Uturuncu volcano, Journal of Petrology, 55(4), 749–767.
This work was conducted in collaboration with the Instituto Geofisico in Ecuador. It was focused on a period of unrest in 2001 and 2002 that did not lead to an eruption. I used the patterns of deformation and seismicity to constrain the cause of the unrest. I then used these results to elucidate the signals that might be expected in the future if the volcano transitions into another unrest period that might be a prelude to a forthcoming eruption.
Paper (open access): Hickey, J., Gottsmann, J., & Mothes, P. (2015) Estimating volcanic deformation source parameters with a finite element inversion: The 2001–2002 unrest at Cotopaxi volcano, Ecuador. Journal of Geophysical Research: Solid Earth, 120(3), 1473-1486.
Sakurajima Volcano & Aira Caldera
After seeing this volcano erupt while in attendance at the IAVCEI conference in July of 2013 I knew it was always going to be one of my favourites. It soon became a case study for the models I was developing. In collaboration with the Sakurajima Volcano Research Centre in Japan, I tested how the incremental addition of extra model complexities can alter model results. The results were clear: the incorporation of additional geophysical and geological data massively improved the model results. Interpretation of the results showed that Sakurajima might be building towards a large eruption – similar in scale to an eruption there in 1914 that killed 58 people.
Paper (open-access): Hickey, J., Gottsmann, J., Nakamichi, H., & Iguchi, M. (2016) Thermomechanical controls on magma supply and volcanic deformation: application to Aira caldera, Japan. Scientific Reports, 6, 32691.