There is much we still don't understand about how volcanoes work and these are some of the questions I'm seeking to answer in my research:
  • How do volcanoes interact with ice?
  • What makes volcanic eruptions explosive?
  • How are lava domes emplaced?
  • How are volcanic earthquakes triggered?

    More detailed information about my research interests is given below:

    Volcano-ice interactions

    What controls the mechanisms of subglacial eruptions? How can we reconstruct palaeo-ice thicknesses during subglacial eruptions? How will current climate change affect hazards at ice-covered volcanoes?

    To address these and other questions I am involved in collaborative projects with AXA Fellow Jacqui Owen, as well as collaborators including Dave McGarvie, Jon Castro, Magnus Gudmundsson and others. Techniques used include field study of subglacial volcanic deposits, geochemical analysis and mathematical modelling.

    To date the fieldwork has primarily focussed on the products of subglacial rhyolite eruptions at Torfajokull and Krafla volcanoes in Iceland. My initial studies focussed on the volcanic facies formed in different styles of rhyolitic eruptions under ice. More recently Jacqui Owen has characterised chamber-to-surface degassing in eruptions at Torfajokull and discovered that explosive eruptions are driven by gas, rather than interactions with meltwater. We have used volatile contents and fracture patterns in subglacially-erupted lavas to reconstruct Quaternary palaeo-environments in Iceland and Chile.

    I have also developed mathematical models that simulate how ice melts and deforms during subglacial eruptions and explore the feedbacks between eruption mechanisms and the response of the ice.

    More recently I have looked at the use of degassing to reconstruct palaeo-ice thicknesses, with early techniques being greatly refined in a series of papers from Jacqui Owen's PhD thesis. Finally, I have written a paper assessing how melting of ice on volcanoes may affect their future activity.

    [modelling eruptions under ice]

    [fieldwork in the Chilean Andes]

    Selected relevant publications:
    --Forbes, A.E.S., Blake, S., McGarvie, D.W., Tuffen, H. (2014) Entablature: fracture types and mechanisms. Bulletin of Volcanology 76: 820, DOI 10.1007/s00445-014-0820-z.
    --Owen, J., Tuffen, H., McGarvie, D.W. (2013) Pre-eruptive volatile content, degassing paths and depressurisation explaining the transition in style at the subglacial rhyolitic eruption of Dalakvísl, South Iceland. Journal of Volcanology and Geothermal Research 258, 143–162. doi:10.1016/j.jvolgeores.2013.03.021.
    --Owen, J., Tuffen, H., McGarvie, D.W. (2013) Explosive subglacial rhyolitic eruptions in Iceland are fuelled by high magmatic H2O and closed system degassing. Geology, doi:10.1130/G33647.1.
    --Owen. J., Tuffen, H., McGarvie, D.W. (2012) Using dissolved H2O in rhyolitic glasses to estimate palaeo-ice thickness during a subglacial eruption at Bláhnúkur (Torfajökull, Iceland). Bulletin of Volcanology 74, 1355-1378, doi: 10.1007/s00445-012-0601-5.
    --Forbes, A.E.S., Blake, S., McGarvie, D.W., Tuffen, H., (2012) Pseudopillow fracture systems in lavas: Insights into cooling mechanisms and environments from lava flow fractures. Journal of Volcanology and Geothermal Research, 245–246, 68–80, doi: 10.1016/j.jvolgeores.2012.07.007.
    Tuffen, H., Owen J, Denton JS. (2010) Magma degassing during subglacial eruptions and its use to reconstruct palaeo-ice thicknesses. Earth Science Reviews, doi: 10.1016/j.earscirev.2010.01.001.
    --Tuffen, H. Will melting of ice affect volcanic hazards in the 21st century? Philosophical Transactions of the Royal Society A, in review.
    --Tuffen, H., Castro, J.M. (2009) The emplacement of an obsidian dyke through thin ice: Hrafntinnuhryggur, Krafla, Iceland. Journal of Volcanology and Geothermal Research, doi:10.1016/j.jvolgeores.2008.10.021.
    --Tuffen, H., McGarvie, D.W., Pinkerton, H., Gilbert, J.S., Brooker R. (2008) An explosive-intrusive subglacial rhyolite eruption at Dalakvísl, Torfajökull, Iceland. Bulletin of Volcanology, 70, 841–860, DOI:10.1007/s00445-007-0174-x.
    --Tuffen, H. (2007) Models of ice melting and edifice growth during subglacial basaltic eruptions. Journal of Geophysical Research 112, B03203, doi:10.1029/2006JB004523.
    --Tuffen, H., McGarvie, D.W., Pinkerton, H., Gilbert, J.S., Brooker R. (2007) An explosive-intrusive subglacial rhyolite eruption at Dalakvísl, Torfajökull, Iceland. Bulletin of Volcanology, DOI:10.1007/s00445-007-0174-x.
    --Mee, K., Tuffen, H., Gilbert, J.S. (2006) Snow-contact volcanic facies at Nevados de Chillan volcano, Chile, and implications for reconstructing past eruptive environments. Bulletin of Volcanology, 68, 363-376.
    --Schopka, H.H., Guðmundsson, M.T., Tuffen, (2006) The formation of Helgafell, SW-Iceland, a monogenetic subglacial hyaloclastite ridge: Sedimentology, hydrology and ice-volcano interaction. Journal of Volcanology and Geophysical Research, 152, 359-377.
    --Tuffen, H., Gilbert J.S., McGarvie D.W. (2001) Products of an effusive subglacial rhyolite eruption: Bláhnúkur, Torfajökull, Iceland. Bulletin of Volcanology 63, 179-190.

    What controls the explosivity of volcanic eruptions?

    In this NERC-funded fellowship project I am investigating to what extent degassing controls the explosivity of rhyolitic eruptions. The patterns of degassing during two important eruptions, at Taupo (New Zealand) and Mono Craters (California) are studied by analysing the dissolved volatile concentrations in fragments of pumice and ash from different layers. State-of-the-art micro-analytical techniques will be used to shed new light on the timescale of gas loss and will allow volatiles in pumiceous material to be analysed for the first time.

    [bubbles in Taupo ash]

    [modelling diffusion in magma]

    Selected relevant publications:
    --Castro, J.M., Beck, P., Tuffen, H., Nichols, A., Dingwell, D.B. (2008) Timescales of spherulite crystallization in obsidian inferred from water concentration profiles. American Mineralogist.
    --Tuffen, H., McGarvie, D.W., Pinkerton, H., Gilbert, J.S., Brooker R. (2008) An explosive-intrusive subglacial rhyolite eruption at Dalakvísl, Torfajökull, Iceland. Bulletin of Volcanology, 70, 841–860, DOI:10.1007/s00445-007-0174-x.
    --Tuffen, H., Castro, J.M., Wilson L. The thermal effects of spherulite growth in rhyolitic lava.

    Volcanic earthquakes and fracture of hot lava

    My research addresses how fractures and faults develop in highly-viscous silicic lavas such as lava domes or obsidian flows. One part of this research involves high-temperature deformation experiments on lava from Mt St Helens, in collaboration with colleagues at UCL. We are measuring the fracture mechanics properties of hot lava and comparing the micro-earthquakes given off during experiments with seismicity recorded at Mt St Helens. I am also looking at the geological record of fracturing and faulting in lava from a number of volcanoes and exploring links between fracturing, degassing and seismicity.

    [a high-T fault in obsidian]

    [results of a high-T fracture experiment]

    Selected relevant publications:
    --Tuffen, H., Smith, R., Sammonds, P. (2008) Evidence for seismogenic fracture of silicic magma. Nature 253, 511-514, DOI:10.1038/nature06989.
    --Neuberg J.W., Tuffen, H., Collier L., Green D., Powell T. and Dingwell D.B. (2006) The trigger mechanism of low-frequency earthquakes on Montserrat. Journal of Volcanology and Geothermal Research, 153, 37–50.
    --Tuffen, H., Dingwell, D.B. (2005) Fault textures in volcanic conduits: evidence for seismic trigger mechanisms during silicic eruptions. Bulletin of Volcanology, 67, 370–387.
    --Tuffen, H., Dingwell, D.B., and Pinkerton, H. (2003) Repeated fracture and healing of silicic magma generate flow banding and earthquakes? Geology 31, 1089-1092.

    Volcanoes and people

    I'm involved in "Erupting Conversations", a Lancaster-based collaboration between natural and social scientists that explores tensions between traditional and western worldviews amongst the volcanoes of Ecuador.
    In a collaboration with archaeologists at Manchester I have helped to investigate the provenance of Neolithic obsidian artefacts in eastern Turkey through studies of the texture of obsidian artefacts and source lava flows.

    [Neolithic obsidian knife]

    [volcano mural, Banos, Ecuador (Z. Young)]

    Dr. Hugh Tuffen
    Royal Society University Research Fellow