Research Fellow - Volcanology / Director (Montserrat Volcano Observatory)
MPhys (Physics with Technological Physics)
PhD (Physical Volcanology)
17 years’ experience in volcanology and geothermal geophysics. Using geophysics to better understand the nature and behaviour of magmatic systems and fluid flow through geothermal systems.
My interest in volcanology was first piqued by the eruption of the Soufrière Hills Volcano in Montserrat, W.I. when I started out as a volunteer at the volcano observatory in 1996. Following my undergraduate studies in Physics I completed a PhD in volcanology. During my PhD research I performed controlled explosions in the laboratory to simulate repetitive volcanic explosions and magma flow in volcanic conduits.
After my PhD I returned to the Montserrat Volcano Observatory and where I worked as a volcanologist for five years combining volcano monitoring with research. My research covered remote gas sensing, ground deformation associated with the magmatic system and dome volume estimation.
Following my time at the MVO I worked for six years at the University of Auckland in New Zealand. At Auckland my primary focus was determining fluid flow pathways in geothermal systems, particularly with an eye to targeting geothermal wells for energy production. Whilst based in New Zealand I worked on systems in several countries including Montserrat, New Zealand, Rwanda, Chile and the USA. I developed novel methodologies for modelling subsurface geothermal systems using joint interpretation of data sets. I also developed expertise in electromagnetic induction, particularly the magnetotelluric technique, a useful technique for imaging systems deep within the Earth’s crust. I also taught short courses in both general geothermal technology and magnetotellurics.
My current interests include ground deformation associated with the volcanic systems of the Eastern Caribbean and the use of joint interpretation and inversion to determine the architecture of geothermal and magmatic systems in the region. I have published over 20 articles and book chapters in peer-reviewed international publications.
- Ground deformation associated with active magmatic systems
- Volcano geophysics
- Geothermal geophysics
- Geothermal exploration and monitoring
- Joint interpretation and inversion to determine the structure of magmatic and geothermal systems
- Seismic velocity as a proxy for temperature in geothermal systems
- Magnetotellurics for imaging magmatic and geothermal systems
Book sections (peer-reviewed)
- Odbert, H. M., G. A. Ryan, G. S. Mattioli, S. Hautmann, J. Gottsmann, N. Fournier, and R. Herd (2014), Volcano geodesy at Soufrière Hills Volcano: A review, in The Eruption of Soufriere Hills Volcano, Montserrat from 2000 to 2010, edited by G. Wadge, R. Robertson and B. Voight, pp. 195-217, Geological Society of London.
- Voight, B., R. S. J. Sparks, E. Shalev, T. Minshull, M. Paulatto, C. Annen, C. Kenedi, J. Hammond, T. Henstock, L. Brown, E. Kiddle, P. Malin, G. Mattioli, L. Carothers, A. Belousov, A. Clarke, L. Ellett, D. Elsworth, D. Hidayat, R. Herd, A. Johnson, A. Lee, A. Miller, B. Murphy, C. Pierce, G. Ryan, S. Saldana, C. Snelson, R. Stewart, R. Syers, C. Widiwijayanti, S. R. Young and W. Zamora (2013), The SEA-CALIPSO volcano imaging experiment at Montserrat: plans, campaigns at sea and on land, scientific results, and lessons learned, in The Eruption of Soufrière Hills Volcano, Montserrat from 2000 to 2010, edited by G. Wadge, R. E. A. Robertson and B. Voight, pp. 253-289, Geological Society, London.
- Lane, S. J., J. C. Phillips, and G. A. Ryan (2008), Dome-building eruptions: insights from analogue experiments, in Fluid motions in Volcanic conduits: A Source of Seismic and Acoustic Signals, edited by S. J. Lane and J. S. Gilbert, pp. 207-237, Geological society, London.
- Bonadonna, C., Mayberry, G.C., Calder, E.S., Sparks, R.S.J., Choux, C., Jackson. P., Lejeune, A.M., Loughlin, S.C., Norton, G.E., Rose, W.I., Ryan G. & Young, S.R. (2002). Tephra fallout in the eruption of Soufrière Hills Volcano, Montserrat. In The eruption of the Soufrière Hills Volcano, Montserrat, from 1995 to 1999, T.H. Druitt & B.P. Kokelaar (eds.), pp. 483-516, Geological Society, London, Memoirs, 21.
- Druitt, T.H., Young, S.R., Baptie, B., Bonadonna, C., Calder, E.S., Clarke, A.B., Cole P.D., Harford, C.L., Herd, R.A., Luckett, R., Ryan G. & Voight, B. (2002). Episodes of cyclic vulcanian explosive activity at Soufrière Hills Volcano, Montserrat. In: T.H. Druitt and B.P. Kokelaar (eds), pp. 281-306, The eruption of the Soufrière Hills Volcano, Montserrat, from 1995 to 1999, Geological Society, London, Memoirs, 21.
- Ryan, G. A. (2002). The flow of rapidly decompressed gum rosin di-ethyl ether and implications for volcanic eruption mechanisms. PhD, Lancaster University.
Journal articles (peer-reviewed)
- Neuberg, J.W., Taisne, B., Burton, M., Ryan, G.A., Calder, E., Fournier, N., Collinson, A.S.D. (May 2022). A review of tectonic, elastic and visco-elastic models exploring the deformation patterns throughout the eruption of Soufrière Hills volcano on Montserrat, West Indies. Journal of Volcanology and Geothermal Research. Volume 425. https://doi.org/10.1016/j.jvolgeores.2022.107518
- Basant, Racine, Lynne, Bridget Y., Ramsook, Ryan., Ryan, Graham A., Blake, Oshaine O., Utley, James E.P. (March 2022) Utilizing cores for characterising the temperature and permeability regimes in a litho-stratigraphic model of the Montserrat geothermal system, Montserrat (Lesser Antilles arc, West Indies). Geothermics. https://doi.org/10.1016/j.geothermics.2021.102341
- E. P. Joseph, M. Camejo-Harry, T. Christopher, R. Contreras-Arratia, S. Edwards, O. Graham, M. Johnson, A. Juman, J. L. Latchman, L. Lynch, V. L. Miller, I. Papadopoulos, K. Pascal, R. Robertson, G. A. Ryan, A. Stinton, R. Grandin, I. Hamling, M-J. Jo, J. Barclay, P. Cole, B. V. Davies & R. S. J. Sparks (2022): Responding to eruptive transitions during the 2020-2021 eruption of La Soufrière volcano, St. Vincent. Nature Communications 13 (4129 (2022)), 10.1038/s41467-022-31901-4
- Ryan, G. A., and E. Shalev (2014.), Seismic velocity / temperature correlations and a possible new geothermometer: insights from exploration of a high-temperature geothermal system on Montserrat, West Indies, Energies, 7(10), 6689-6720. (invited article for special issue “Geothermal Energy: Delivering on the Global Potential”)
- Ryan, G.A., S.A., Peacock, J., Rugis, J., Shalev, E. (2013) Montserrat geothermal system: a 3D conceptual model, Geophysical Research Letters, 40, 2038-2043, doi: 10.1002/grl.50489.
- Bertrand, E. A., T. G. Caldwell, G. J. Hill, E. L. Wallin, S. L. Bennie, N. Cozens, S. A. Onacha, G. A. Ryan, C. Walter, A. Zaino, and P. Wameyo (2012), Magnetotelluric imaging of upper-crustal convection plumes beneath the Taupo Volcanic Zone, New Zealand, Geophysical Research Letters, 39, pp. 6, L02304, DOI:10.1029/2011GL050177.
- Ryan, G. A., S. C. Loughlin, M. R. James, L. D. Jones, E. S. Calder, T. Christopher, M. H. Strutt, and G. Wadge (2010), Growth of the lava dome and extrusion rates at Soufrière Hills Volcano, Montserrat, West Indies: 2005-2008, Geophysical Research Letters, 37, pp. 5, L00E08, DOI: 10.1029/2009GL041477.
- Loughlin, S. C., R. Luckett, G. Ryan, T. Christopher, V. Hards, S. De Angelis, L. Jones, and M. Strutt (2010), An overview of lava dome evolution, dome collapse and cyclicity at Soufrière Hills Volcano, Montserrat, 2005-2007, Geophysical Research Letters, 37, pp. 6, L00E16, DOI: 10.1029/2009GL041477.
- Mattioli, G. S., R. A. Herd, M. H. Strutt, G. Ryan, C. Widiwijayanti, and B. Voight (2010), Long term surface deformation of Soufrière Hills Volcano, Montserrat from GPS geodesy: Inferences from simple elastic inverse models, Geophysical Research Letters, 37, pp. 6, L00E13, doi:10.1029/2009GL042268.
- Le Friant, A., C. Deplus, G. Boudon, N. Feuillet, J. Trofimovs, J. C. Komorowski, R. S. J. Sparks, P. Talling, S. Loughlin, M. Palmer, and G. Ryan (2010), Eruption of Soufrière Hills (1995-2009) from an offshore perspective: Insights from repeated swath bathymetry surveys, Geophysical Research Letters, 37(11), pp. 6, L11307, doi:10.1029/2010GL043580.
- Paulatto, M., T. A. Minshull, B. Baptie, S. Dean, J. O. S. Hammond, T. Henstock, C. L. Kenedi, E. J. Kiddle, P. Malin, C. Peirce, G. Ryan, E. Shalev, R. S. J. Sparks, and B. Voight (2010), Upper crustal structure of an active volcano from refraction/reflection tomography, Montserrat, Lesser Antilles, Geophysical Journal International, 180(2), 685-696.
- Wadge, G., G. Ryan, and E. S. Calder (2009), Clastic and core lava components of a silicic lava dome, Geology, 37, 551-554, DOI: 10.1130/G25747A.1.
- Wadge, G., R. Herd, G. Ryan, E. S. Calder, and J. C. Komorowski (2009), Lava production at Soufrière Hills Volcano, Montserrat: 1995-2009, Geophysical Research Letters, 37, pp. 5, L00E03, doi: 10.1029/2009GL041466.
- Hale, A. J., E. S. Calder, S. C. Loughlin, G. Wadge, and G. A. Ryan (2009), Modelling the lava dome extruded at Soufrière Hills Volcano, Montserrat, August 2005-May 2006. Part II: Rockfall activity and talus deformation, Journal of Volcanology and Geothermal Research, 187, 69-84.
- Hale, A. J., E. S. Calder, G. Wadge, S. C. Loughlin, and G. A. Ryan (2009), Modelling the lava dome extruded at Soufrière Volcano, Montserrat, August 2005-May 2006. Part I: Dome shape and internal structure, Journal of Volcanology and Geothermal Research, 187, 53-68.
- Wadge, G., Macfarlane, D. G., Odbert, H. M., James, M. R., Hole, J. K., Ryan, G., Bass, V., De Angelis, S., Pinkerton, H., Robertson, D. A. & Loughlin, S. C. (2008) Lava dome growth and mass wasting measured by a time series of ground-based radar and seismicity observations. Journal of Geophysical Research, 113, pp. 15, B08210, doi:10.1029/2007JB005466.
- Luckett, R., Loughlin, S., De Angelis, S. and Ryan, G. (2008) Volcanic seismicity at Montserrat, a comparison between the 2005 dome growth episode and earlier dome growth. Journal of Volcanology and Geothermal Research, 177(4): 894-902.
- Rodríguez, L. A., Watson, I. M., Edmonds, M., Ryan, G., Hards, V., Oppenheimer, C. M. M. and Bluth, G. J. S. (2008) SO2 loss rates in the plume emitted by Soufrière Hills volcano, Montserrat. Journal of Volcanology and Geothermal Research, 173, 135-147.
- De Angelis S., Bass V., Hards V., Ryan G. (2007). Seismic characterization of pyroclastic flow activity at Soufrière Hills Volcano, Montserrat, 08 January 2007. Natural hazards and Earth System Sciences, 7(4), 467-472.
- Trofimovs J., Amy L., Boudon G., Deplus C., Doyle E., Fournier N., Hart M.B., Komorowski J.C., Le Friant A., Lock E.J., Pudsey C., Ryan G., Sparks R.S.J., Talling P.J. (2006). Submarine pyroclastic deposits formed at the Soufrière Hills Volcano, Montserrat (1995-2003): What happens when pyroclastic flows enter the ocean? Geology, 34 (7), 549-552.
- Lane, S.J., Chouet, B.A., Phillips, J.C., Dawson, P., Ryan, G.A., Hurst, E. (2001). Experimental observations of pressure oscillations and flow regimes in an analogue volcanic system. Journal of Geophysical Research, 106(B4), 6461-6476.
- Koros, W., J. O’Sullivan, J. Pogacnik, M. O’Sullivan, and G. A. Ryan (2015), Comparison of coupled one-dimensional subsidence models, in World Geothermal Congress., pp. 10
- Brophy, P., B. Poux, G. Suemnicht, P. Hirtz, and G. Ryan (2014), Preliminary Results of Deep Geothermal Drilling and Testing on the Island of Montserrat, Stanford Geothermal Workshop, Stanford, California, USA, pp. 11
- Walter, C., A. G. Jones, and G. A. Ryan (2013), Three-dimensional magnetotelluric imaging of the Reporoa/Waiotapu geothermal system, New Zealand, Proceedings of the New Zealand Geothermal Workshop, Rotorua, New Zealand., pp. 9
- Leary, P., P. Malin, G. A. Ryan, C. Lorenzo, and M. Flores (2013), Lognormally Distributed K/Th/U Concentrations – Evidence for GeoCritical Fracture Flow, Los Azufres Geothermal Field, MX, GRC Transactions, 37, pp. 8
- Ryan, G. A. (2017) The University of the West Indies, Seismic Research Centre, GW4+ Applied Volcanology workshop, Bristol, U.K.
- Walter, C., A. Jones, G. A. Ryan (2014) The importance of smoothing parameters and starting models in 3D inverse modelling: An example from the Taupo volcanic zone, New Zealand, Electromagnetic Induction Workshop, Weimar, Germany.
- Walter, C., A. Jones, G. A. Ryan (2013) Magnetotelluric imaging of the Reporoa geothermal system in New Zealand, vol. 15, EGU2013-3572-1, European Geophysical Union General Assembly, Vienna, Austria.
- Walter, C., A. G. Jones, and G. A. Ryan (2013), Three-dimensional magnetotelluric imaging of the Taupo volcanic zone: an example of the Reporoa/Waiotapu geothermal system, New Zealand, IAGA, Merida, Mexico.
- Voight, B., R. S. J. Sparks, J. Hammond, C. Annen, E. J. Kiddle, T. Minshull, M. Paulatto, T. Henstock, S. Dean, E. Shalev, P. Malin, C. Kenedi, G. A. Ryan, G. S. Mattioli, L. Brown, K. Byerly, C. J. Ammon, D. Elsworth, V. Miller, W. Sevilla, D. Hidayat, C. Widiwijayanti, A. Belousov, L. Carothers, M. R. Johnson, W. Zamora, B. Murphy, L. Ellett, C. M. Snelson, S. Saldana, B. Christensen, C. Pierce, R. A. Herd, A. B. Clarke, A. Linde, S. Sacks, V. Bass, T. Christopher, S. De Angelis, V. Hards, S. C. Loughlin, M. H. Strutt, and R. Syers (2011), The SEA-CALIPSO active-source seismic experiment finds magma chamber and crustal structure under Soufriere Hills Volcano., Soufrière Hills: 15 years on conference, Montserrat, W. I.
- Mattioli, G. S., D. Elsworth, R. Foroozan, R. A. Herd, G. A. Ryan, M. H. Strutt, B. Voight, and C. Widiwijayanti (2011), Geodetic imaging of Soufriere Hills Volcano, Montserrat from 1995-2009., Soufrière Hills Volcano: 15 years on conference, Montserrat, W. I.
- Kenedi, C. L., and G. Ryan (2010), Evidence for a Fracture Dominated Hydrothermal System at St. George’s Hill, Montserrat, 2010AGUFM.V21E2360K, American Geophysical Union, Fall Meeting, San Francisco, CA.
- Loughlin, S.C., R. Luckett, B. Baptie, T. Christopher, L. Jones, G. A. Ryan, T. H. Druitt, V. Hards, S. A. Carn (2011). Unprecedented gas release from a large volume and rapid, total dome collapse at Soufrière Hills Volcano, Montserrat on 20 May 2006. Soufrière Hills Volcano: 15 years on conference, Montserrat, W.I.
- Odbert, H. M., G. A. Ryan, R.A. herd, G. S. Mattioli, B. Voight, M. H. Strutt, R. Syers, N. Fournier (2011). Ground Deformation of the Soufrière Hills Volcano: past, present and future. Soufrière Hills Volcano: 15 years on conference, Montserrat, W.I.
- Ryan, G. A., S. A. Onacha, E. Shalev and P.E. Malin (2010). The use of magnetotellurics and time domain electromagnetic methods in the geothermal surveys of Montserrat, W.I., GeoNZ, Auckland, New Zealand.
- Bertrand, E. A., T. G. Caldwell, G. J. Hill, E. Wallin, S. L. Bennie, N. Cozens, S. Onacha, G. Ryan, C. Walter, A. Zaino, and R. Malin (2010), Deep geothermal exploration with an array of magnetotelluric data, paper presented at GeoNZ, Auckland, New Zealand.
- Bromley, C. J., Jolly, S., Allis, R. G., Samsonov, S. & Ryan, G. (2008) Update on subsidence at Ohaaki Geothermal Field. Proceedings of the New Zealand Geothermal Workshop, Taupo, New Zealand.
- Mann, C.P., Hards, V., Ryan, G. and Stix J. (2007). Nature of magma recharge at Soufrière Hills volcano, Montserrat, West Indies, 2006AGUFM.V11A0555B, American Geophysical Union, Fall Meeting, San Francisco, CA.
- Wadge, G., Macfarlane, D.G., Odbert, H.M., James, M.R., Hole, J.K, Ryan, G., Bass, V., De Angelis, S., Pinkerton, H., Robertson, D.A., Loughlin, S.C. (2007), 2007AFUFM.V21A0390W, Time Series Radar Observations of a Growing Lava Dome, American Geophysical Union Fall meeting, San Francisco, CA.
- Ryan, G.A., James, M.R., Strutt, M.H., Applegarth. L.J. (2006). A photogrammetric method for monitoring lava extrusion rates during dome forming eruptions. Garavolcan 2006, Tenerife.
- Lane, S.J., Ryan, G.A., and Phillips, J.C. (2003). Long time-scale pressure fluctuations in a degassing laboratory fluid with comparison to volcanic tilt cycles, International Union of Geodesy and Geophysics conference, Sapporo, Japan.
- Ryan, G.A., Lane, S.J., Phillips, J.C., Chouet, B.A., Dawson P.P. (1999). Pressure oscillations in experimental foam flows, European Seismological Commission Annual workshop. Santorini, Greece
- Ryan, G. A., S. A. Onacha, E. Shalev, and P. E. Malin (2012), The use of Magnetotelluric and Time domain electromagnetic methods in the geothermal survey of Montserrat, W.I., EM Induction Workshop, Darwin, Australia (poster)
- Ryan, G.A., Lane, S.J., Phillips, J.C. (1999). Fragmentation behaviour of a laboratory analogue to explosive magmatic flows, International Union of Geodesy and Geophysics conference (poster presentation), Birmingham, U.K.