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Accueil > Documents > Pages personnelles > GAREL Fanny

Research : lava flows


Publications


  • Cordonnier B., Lev E., Garel F., Benchmarking lava-flow models, 2016, in Detecting, Modelling and Responding to Effusive Eruptions, Geological Society, London, Special Publications 426, p.425-445, doi:10.1144/SP426.7
  • Garel F., Kaminski E., Tait S., Limare A., A fluid dynamics perspective on the interpretation of the surface thermal signal of lava flows, 2016, in Detecting, Modelling and Responding to Effusive Eruptions, Geological Society, London, Special Publications 426, p. 243-256, doi:10.1144/SP426.6
  • F. Garel, E. Kaminski, S. Tait, and A. Limare, An analogue study of the influence of solidification on the advance and surface thermal signature of lava flows, Earth and Planetary Science Letters, 396, pp. 46-55, doi:10.1016/j.epsl.2014.03.061, 2014.
  • F. Garel, E. Kaminski, S. Tait, and A. Limare, The influence of wind on the estimation of lava effusion rate from thermal remote-sensing, Journal of Volcanology and Geothermal Research, 264, pp. 223-230, doi:10.1016/j.jvolgeores.2013.08.006, 2013.
  • F. Garel, E. Kaminski, S. Tait, and A. Limare, An experimental study of the surface thermal signature of hot subaerial isoviscous gravity currents : Implications for thermal monitoring of lava flows and domes , Journal of Geophysical Research, 117, B02205 doi:10.1029/2011JB008698, 2012.
  • G. Hetényi, B. Taisne, F. Garel, E. Médard, S. Bosshard and H. B. Mattsson, Scales of columnar jointing in igneous rocks : field measurements and controlling factors, Bulletin of Volcanology, 74, pp. 457-482, DOI : 10.1007/s00445-011-0534-4, 2012.





My PhD thesis focused on the cooling of lava flows, through a simple theoretical model and analogue experiments. I then continued to work on this subject to provide simple benchmarks that can be reproduced to test the validity of complex numerical models of lava flow inundation hazard.


An issue in operational volcanology is the possibility to predict lava flow advance using remote-sensed thermal images.


This problem involves a study of the physical coupling between the spreading and the cooling of a lava flow, to understand how the thermal heat flux can be used to assess the effusion rate, and how the effusion rate controls the advance of a flow with a complex rheology.

The issue is to understand the temporal evolution of the surface thermal signal of a flow depending on its input rate and rheology.



We first study the evolution of an axisymmetric horizontal viscous gravity current (silicone oil), injected with a constant supply rate at a hot temperature and cooling while spreading into the air. The images below display the visible photograph (top) and the thermal IR image (bottom) taken during one experiment.

PNG - 488.7 ko

The surface thermal signature of the current becomes constant after a certain time. Scaling this simple model for basaltic lava flows, we obtain that the effusion rate could be retrieved from one single thermal survey after a few days. See the published article for further details.



I then studied the deviation from this ideal newtonian behaviour using PEG wax undergoing solidification away from the source. We observe periodic overflowing of the liquid wax over the solidified material, associated with renewed surface thermal signals (see the published article).





I also focus on the inertia of the surface thermal signal compare to instantaneous change in the supply rates. The images below present the evolution of hot glucose syrup (temperature-dependent viscosity) injected where the supply rate is divided by three in the middle of the experiment (top to bottom, left column to right column).