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Ashley Davies

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4800 Oak Grove Drive
M/S 183-501

Pasadena, CA 91109





Curriculum Vitae:

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Member of:

Planetary Geosciences


Dr. Davies is a Principal Scientist at the Jet Propulsion Laboratory, California Institute of Technology. A geologist and planetary scientist specialising in volcanology, he is an expert in the acquisition, interpretation and modelling (both analytically and numerically) of remote sensing data of volcanic eruption processes, especially on Io (the hyperactive volcanic moon of Jupiter) and at terrestrial analogues of Io’s volcanoes. These investigations have taken Dr. Davies to ongoing volcanic eruptions at the ends of the Earth. His work has led to methodologies for interpreting remote sensing infrared data to identify and quantify the volcanic eruption processes taking place, leading to innovative instrument designs for studying volcanic activity.

Dr. Davies was a member of the Galileo Near Infrared Mapping Spectrometer (NIMS) team and continues to quantitatively analyse the unique NIMS Io dataset. He is a Co-Investigator on the Mapping Imaging Spectrometer for Europa (MISE) instrument on NASA’s new Europa Clipper mission, and is a Co-Investigator on the Io Volcano Observer, a finalist in the NASA Discovery 2019 competition. He has authored or co-authored over 100 refereed papers on modelling and understanding volcanic eruptions on Earth, Io, and elsewhere in the Solar System and is the author of “Volcanism on Io”, published by Cambridge University Press. He was the Science Lead on the successful Autonomous Sciencecraft Experiment that flew on Earth Observing-1; is the Lead Scientist on the JPL Volcano Sensor Web project; and is an associate member of the Terra ASTER Team. He is the manager of the ASTER Volcano Archive, which is based at JPL.

His terrestrial studies provide understanding of distant Io’s eruptions, planetary heat flow, and role within the orbital resonance that ultimately drives Io’s volcanic activity; and the study of Io similarly reveals insights into volcanic eruption processes that helped shape the surface of Earth, the Moon, and the other terrestrial planets in their distant pasts, as they are actively reshaping Io today.


  • B.Sc (Hons.) in Astronomy and Geology, Hatfield Polytechnic, Hatfield, Herts. UK (1984)
  • Ph.D. in Volcanology, Lancaster University, Lancaster, UK (1988)

Professional Experience

  • Jet Propulsion Laboratory (1996 - present)
    • Principal Scientist (2020), Planetary Geophysics
    • Mapping Imaging Spectrometer for Europa (MISE) Co-I (2015-Present)
    • NMP-Autonomous Sciencecraft Experiment Lead Scientist (2001-present)
    • ASTER Team Associate (2004-present)
    • Research Scientist, Comets, Asteroids and Satellites Group (2003 - present)
    • Research Scientist, Galileo NIMS team (2001-2002)
    • Scientist, Galileo NIMS team (1996-2001)
  • National Research Council Resident Research Associate, NASA JPL (1994-1996)
  • UK Meteorological Office: Higher Scientific Officer (1990 - 1994)
    • ARTIFAX Systems Programmer (1990-1991)
    • Short-Range Forecast Division (Research Scientist)

Research Interests

  • Planetary science: in particular, the jovian satellite Io
  • Remote sensing of volcanic activity
  • Hyperspectral and multispectral data analysis
  • Numerical and analytical modelling of volcanic processes on Io, Earth, and icy satellites
  • Autonomous spacecraft and sensor web operations
  • Infrared imager development

Selected Awards

  • JPL Voyager Award (for management of Group 3223) (2020)
  • NASA Software of the Year: Honourable mention: "Sensor Web Toolbox" (2011)
  • NASA Space Act Award: "Autonomous Volcano Sensor Web" (2007)
  • NASA Software of the Year - Autonomous Sciencecraft Experiment (2005)
  • NASA Group Achievement Award for the Autonomous Sciencecraft Experiment Team (2005)
  • NASA Tech Brief award "Software for Onboard Science Analysis" (2003)
  • JPL Team Bonus Award: "Jupiter Icy Moon Orbiter (JIMO) Studies" (2003)
  • NASA Group Achievement Award to the Galileo Project Team (1998)
  • National Research Council Postdoctoral Fellowship (1994-1996)

Selected Publications


  • Davies, A. G. "Volcanism on Io: A Comparison with Earth", Cambridge University Press, 372 pages, 2007.

Journal Articles

  • Davies, A. G. (2022) Cautionary Analysis of Spectral Radiance from Io’s Active Volcanoes Derived from Galileo Near-Infrared Mapping Spectrometer Data. Astro. J., 163, 2, 9 pages.
  • Mura, A. Adriani, F. Tosi, R. Lopes, G. Sindoni, G. Filacchione, D.A. Williams, A. G. Davies, C. Plainaki, S. Bolton, F. Altieri, A. Cicchetti, D. Grassi, A. Migliorini, M. L. Moriconi, R. Noschese, A. Olivieri, G. Piccioni and R. Sordini (2020) Infrared observations of Io from Juno. Icarus, 341, 1 May 2020, 113607.
  • de Kleer, K. I. de Pater, E. Molter, E. Banks, A. G. Davies, C. Alvarez. R. Campbell, J. Aycock, J. Pelletier, G. Puniwai, T. Stickel, D. Eugenio, N. M. Nielsen, D. Stern, and J. Tollefson (2019) Io's Volcanic Activity from Time-Domain Adaptive Optics Observations: 2013-2018, Astron. J., 158, 29, 14 pages
  • Davies, A. G., R. L. Davies, G. J. Veeder, K. de Kleer, I. de Pater, D. L. Matson, T. V. Johnson and L. Wilson (2018) Discovery of a Powerful, Transient, Explosive Thermal Event at Marduk Fluctus, Io, in Galileo NIMS Data, GRL, 45, 2926-2933.
  • Davies, A. G., S. Gunapala, A. Soibel, D. Ting, S. Rafol, M. Blackwell, P. O. Hayne, M. Kelly (2017) A novel technology for measuring the eruption temperature of lavas with remote sensing: application to Io and other planets, JVGR, 343, 1-16. doi: 10.1016/j.jvolgeores.2017.04.016. de Kleer, K, M. Skrutskie, J. Leisening, A. G. Davies, A. Conrad, I. de Pater, A. Resnick, V. Bailey, D. Defrére, P. Hinz, A. Skemer, E. Spalding, A. Vaz, C. Veillet and C.E. Woodward (2017) Multi-phase volcanic resurfacing of Io's Loki Patera, Nature, 545, 199-202. doi:10.1038/nature22339.
  • de Pater, I., K. de Kleer, A. G. Davies and M. Ádámkovics (2017) Three Decades of Loki Patera Observations, Icarus, 297, 265-281 doi: 10.1016/j.icarus.2017.03.016.
  • Davies, A. G., L. P. Keszthelyi and A. S. McEwen (2016) Determination of Eruption Temperature of Io's Lavas Using Lava Tube Skylights, Icarus, 278, 266-278, doi:10.1016/j.icarus.2016.06.003.
  • Davies, A. G., G. J. Veeder, D. L. Matson and T. V. Johnson (2015) Map of Io's Volcanic Heat Flow, Icarus, 262, 67-78. doi:
  • Davies, A. G., Chien, S., Tran, D. and Doubleday, J. (2015) The NASA Volcano Sensor Web, Advanced Autonomy, and the Remote Sensing of Volcanic Eruptions, Chapter in the Geological Society of London-IAVCEI book "Detecting, Modeling and Responding to Effusive Eruptions", eds. A. J. L. Harris, T. De Groove, P. Labazuy and S. Carn, GSA, London, UK.
  • Davies, A. G., G. J. Veeder, S. I. Hill, D. L. Matson and T. V. Johnson (2014) Charting thermal emission variability at Amirani with the Galileo NIMS Io Thermal Emission Database (NITED), Icarus, 241, 190-199. doi: 10.1016/j.icarus.2014.06.034.
  • de Pater, I., Davies, A.G., Ádámkovics, M., Ciardi, D.R (2014) Two New, Rare, High-Effusion Outburst Eruptions at Rarog and Heno Paterae on Io. Icarus, 242, 365-378. doi: 10.1016/j.icarus.2014.06.016.
  • Davies, A. G., S. Chien, J. Doubleday, D. Tran, T. Thordarson, M. T. Gudmundsson, Á. Höskuldsson, S. S. Jakobsdóttir, R. Wright and D. Mandl (2013) Observing Iceland's Eyjafjallajökull 2010 Eruptions with the Autonomous NASA Volcano Sensor Web, JGR-Solid Earth, 118, 1-21, doi:10.1002/jgrb.50141.
  • Davies, A. G., G. J. Veeder, D. L. Matson and T. V. Johnson (2012) Charting thermal emission variability at Pele, Janus Patera and Kanehekili Fluctus with the Galileo NIMS Io Thermal Emission Database (NITED), Icarus, 221, 466-470. doi:10.1016/j.icarus.2012.04.01.
  • Matson, D. L., J. C. Castillo-Rogez, A. G. Davies, T. V. Johnson and J. Lunine (2012) Enceladus: A Hypothesis For Bringing Both Heat And Chemicals To the Surface, Icarus, 221, 53-62.
  • Davies, A. G., G. J. Veeder, D. L. Matson and T. V. Johnson (2012) Charting thermal emission variability at Pele, Janus Patera and Kanehekili Fluctus with the Galileo NIMS Io Thermal Emission Database (NITED), Icarus. In press. doi:10.1016/j.icarus.2012.04.01.
  • Davies, A. G., G. J. Veeder, D. L. Matson and T. V. Johnson (2012) Io: Charting thermal emission variability with the Galileo NIMS Io Thermal Emission Database (NITED): Loki Patera, Geophysical Research Letters, 39, L01201, doi:10.1029/2011GL049999.
  • Davies, A. G., L. Keszthelyi and A. S. McEwen (2011) Estimating Eruption Temperature From Thermal Emission Spectra of Lava Fountain Activity in the Erta'Ale (Ethiopia) Volcano Lava Lake - Implications for Observing Io's Volcanoes, GRL, 38, L21308, doi: 10.1029/2011GL049418.
  • Davies A. G. (2011) Lava lakes on Earth and Io, Planetary Report, vol. XXXI, no. 2, 10-15.
  • Davies A. G. and M. E. Ennis (2011) The variability of volcanic activity at Zamama, Culann, and Tupan Patera on Io as seen by the Galileo Near Infrared Mapping Spectrometer, Icarus, 215, 401-416.
  • Wright, R. H. Garbeil and A. G. Davies (2011) The cooling rate of some active lavas determined using an orbital imaging spectrometer, JGR (Solid Earth), 115, B06205, doi:10.1029/2009JB006536.
  • Davies, A. G., C. Sotin, D. L. Matson, J. C. Castillo-Rogez, T. V. Johnson, M. Choukroun, and K. H. Baines (2010) Atmospheric control of the cooling rate of impact melts and cryolavas on Titan's surface, Icarus, 208, 887-895, doi:10.1016/j.icarus.2010.02.025.
  • Davies, A.G., L. P. Keszthelyi and A. J. L. Harris (2010) The Thermal Signature of Volcanic Eruptions on Io and Earth, JVGR, 194, 75-99, doi:10.1016/j.jvolgeores.2010.04.009.
  • Leone, G., A. G. Davies, L. Wilson, D. A. Williams, L. P. Keszthelyi, W. L. Jaeger and E. P. Turtle (2009) Volcanic history, geologic analysis and map of the Prometheus Patera region on Io, Icarus, 187, 93-105.
  • Davies, A. G., J. Calkins, L. Scharenbroich, R. G. Vaughan, R. Wright, P. Kyle, R. Castańo, S. Chien, and D. Tran (2008) Multi-Instrument Remote and In Situ Observations of the Erebus Volcano (Antarctica) Lava Lake in 2005: a Comparison with the Pele Lava Lake on the Jovian Moon Io, J. Volc. Geotherm. Res., 177, v3, 705-724.
  • Keszthelyi, L. P., W. Jaeger, M. Milazzo, J. Radebaugh, A. G. Davies and K. Mitchell (2007) New estimates for Io eruption temperatures: implications for the interior, Icarus, 192, 491-502.
  • Matson, D. L., A. G. Davies, J. A. Rathbun, G. J. Veeder, T. V. Johnson and J. C. Castillo (2006) Io: Loki Patera as a magma sea, JGR-Planets, 111, E09002, doi:10.1029/2006JE002703.
  • Davies, A. G., L. Wilson, D. L. Matson, G. Leone, L. P. Keszthelyi and W. Jaeger (2006) The pulse of the volcano: discovery of episodic activity at Prometheus on Io, Icarus, 184, 460-477.
  • Davies, A. G., S. Chien, V. Baker, T. Doggett, J. Dohm, R. Greeley, F. Ip, R. Castaňo, B. Cichy, G. Rabideau, D. Tran and R. Sherwood (2006) Monitoring Active Volcanism with the Autonomous Sciencecraft Experiment on EO-1, Rem. Sens. Environ., 101, no. 4, 427-446.
  • Doggett, T., R. Greeley, A. G. Davies, S. Chien, B. Cichy, R. Castano, K. Williams, V. Baker, J. Dohm and F. Ip (2006) Autonomous detection of cryospheric change with Hyperion onboard Earth-Observing 1, Rem. Sens. Environ., 101, no. 4, 447-462.
  • Davies, A. G., S. Chien, R. Wright, A. Miklius, P. R. Kyle, M. Welsh, J. B. Johnson, D. Tran, S. R. Schaffer, and R. Sherwood (2006) Sensor web enables rapid response to volcanic activity, Eos, 87 (1), 1&5.
  • Davies, A. G., D. L. Matson, G. J. Veeder, T. V. Johnson and D. L. Blaney (2005) Post-solidification cooling and the age of Io's lava flows, Icarus, 176, 123-137.
  • Davies, A. G. (2003) Volcanism on Io: estimation of eruption parameters from Galileo NIMS data. J. Geophys. Res., 108, 5106-5120.
  • Davies, A. G., (2003) Temperature, Age and Crust Thickness Distributions of Loki Patera on Io from Galileo NIMS data: Implications for Resurfacing Mechanism. Geophysical Research Letters, 30, 2133-2136.
  • Davies, A. G., L. P. Keszthelyi, D. Williams, C. B. Phillips, A. S. McEwen, R. M. C. Lopes, W.D. Smythe, L. W. Kamp, L. A. Soderblom and R. W. Carlson (2001) Thermal signature, eruption style and eruption evolution at Pele and Pillan on Io. J. Geophys. Res., 106, E12, 33,079-33,104.
  • Williams, D. A., A. G. Davies, L. P. Keszthelyi and R. Greeley (2001) The Summer 1997 eruption at Pillan Patera on Io: implications for ultrabasic lava flow emplacement, J. Geophys. Res., 106, E12, 33,105-33,120.
  • Davies, A. G. (1996) Io's volcanism: thermo-physical models of silicate lavas compared with observations of thermal emission. Icarus, 124, no 1, 45-61