Greg A. Valentine

Professor; Director of the Center for GeoHazards Studies

PhD, Geological Sciences, University of California Santa Barbara – 1988

415 Hochstetter Hall
(716) 645-4295


Volcanic risk, phreatomagmatic explosive eruptions, basaltic volcanic fields, pyroclastic deposits, volcano fluid dynamics, volcaniclastic and surface processes

Research Interests

Physical processes associated with basaltic volcanism, from the scale of eruptive styles at individual volcanoes to the dynamics of basaltic fields. Interpretation of pyroclastic deposits including large-volume, widespread ignimbrites and associated calderas. Multiphase fluid dynamics and numerical modeling of explosive eruptions. Consequences of volcanic activity and spatial-temporal behavior of volcanic systems, with application to risk assessment and coupling to infrastructure response models. Evolution of volcanic landforms, particularly in arid environments.

Course Offerings

  • GLY 215 – Sedimentology
  • GLY 407/507 – Geologic Field Training (Field Camp)
  • GLY 428/528 – Geologic Hazards and Risk
  • GLY 431/531 – Volcanology
  • GLY 433/533 – Volcanic Rocks
  • GLY 578 – Advanced Field Methods
  • GLY 499 – Independent Study
  • GLY 599 – Supervised Teaching
  • GLY 633 – Graduate Research
  • GLY 700 – Thesis Guidance

Current Students

  • Kailey DiemKaye - MS - Experimental studies of pyroclastic flow initiation
  • Andrew Harp – PhD - Plumbing of mafic-intermediate stratovolcanoes.
  • Peter Johnson – PhD - Causes of dewatering events at composite volcanoes as precursors to eruptive episodes.
  • Matthew Sweeney – PhD - Numerical models of magma-water interaction and maar-diatreme eruptions.
  • Scott Borchardt - MS - Basal layer of the upper Bandelier Tuff ignimbrite.
  • Zachary Younger - MS - Emplacement of aa lava at Marcath volcano, Nevada, using LiDAR data.

Recent Former Students

  • Élodie Macorps – MS – “Experimental and field study of host-substrate influence on phreatomagmatic eruptions and the formation of maar-diatremes” – currently pursuing PhD at Univ. South Florida
  • Matthew R. Sweeney – MS – “A numerical determination of debris jet length scales and depositional structures in diatremes” – currently pursuing PhD at UB
  • Andrew Harp – MS - “Shallow plumbing geometry and eruptive processes of a monogenetic volcano, Lunar Crater Volcanic Field, Nevada” – currently pursuing PhD at UB
  • Peter Johnson – MS – “The ~38 ka Marcath eruption at Lunar Crater Volcanic Field, Nevada:  Characteristics of a monogenetic basaltic tephra fall deposit” – currently pursuing PhD at UB
  • Jamal Amin – MS – “Lateral variations in strata competence and alternating eruption styles in space and time as morphological controls on a maar crater in the Lunar Crater Volcanic Field, Nevada, USA” – currently self-employed in start-up business focused on remote sensing.
  • Pascale Bion – MS – “Conception of a method for the creation of volcanic risk index maps”  – currently employed in the Auvergne Department regional government (France)
  • Sonja Melander – MS – “Breccias of the Sovana Eruptive Unit, Latera Caldera, Vulsini Volcanic District, Italy” – currently employed by the Craters of the Moon National Monument and Preserve as the education and outreach coordinator
  • Missti Brown – MS – “Vulnerability assessment for the Mijitayo Creek water treatment facility, Pasto, Colombia” – currently employed by PML Exploration Services LLC


  • Dr. Pranabendu Moitra - 2015 to 2017 - Experimental magma-water interaction.
  • Dr. Alison Graettinger - 2013 to 2016 - Research focus on experimental studies of phreatomagmatic explosive eruptions.

Recent Publications

Valentine GA, White JDL, Ross P-S, Graettinger AH, Sonder I (2017) Updates to concepts on phreatomagmatic maar-diatremes and their pyroclastic deposits.  Frontiers in Earth Science 5:68, doi:10.2289/feart.2017.00068

Amin J, Valentine GA (2017) Compound maar crater and co-eruptive scoria cone in the Lunar Crater Volcanic Field (Nevada, USA).  Journal of Volcanology and Geothermal Research 339: 41-51, doi:10.1016/jvolgeores.2017.05.002

Tadini A, Bevilacqua A, Neri A, Cioni R, Aspinall WP, Bisson M, Isaia R, Mazzarini F, Valentine GA, Vitale S, Baxter PJ, Bertagnini A, Cerminara M, De Michieli Vitturi M, Di Roberto A, Engwell S, Esposti Ongaro T, Flandoli F, Pistolesi M (2017) Assessing future vent opening locations at the Somma-Vesuvio volcanic complex: 2. Probability maps of the caldera for a future Plinian/sub-Plinian event with uncertainty quantification.  Journal of Geophysical Research 122, doi:10.1002/2016JB013858.

Valentine GA, Cortés JA, Widom E, Smith EI, Rasoazanamparany C, Johnsen R, Briner JP, Harp AG, Turrin B (2017) Lunar Crater Volcanic Field (Reveille and Pancake Ranges, Basin and Range Province, Nevada, USA).  Geosphere 13: 391-438, doi:10.1130/GES01428.1

C Bonadonna, R Cioni, A Costa, T Druitt, J Phillips, L Pioli, D Andronico, A Harris, S Scollo, O Bachmann, G Bagheri, S Biass, F Brogi, K Cashman, L Dominguez, T Durig, O Galland, G Giordano, M Gudmundsson, M Hort, A Hoskuldsson, B Houghton, JC Komorowski, U Kueppers, G La Canna, JL Le Pennec, G Macedonio, M Manga, I Manzella, M de’ Michieli Vitturi, A Neri, M Pistolesi, M Polacci, M Ripepe, E Rossi, B Scheu, R Sulpizio, B Tripoli, S Valade, GA Valentine, C Vidal, N Wallenstein (2016) MiMoVolc report on classification and dynamics of volcanic explosive eruptions.  Bulletin of Volcanology 78: 84, doi:10.1007/200445-016-1071-y.

Breard ECP, Lube G, Jones JR, Dufek J, Cronin SJ, Valentine GA, Moebis A (2016) Coupling of turbulent and non-turbulent flow regimes within pyroclastic density currents. Nature Geoscience 9: 767-771, doi:10.1038/NGEO2794

Graettinger AH, Valentine GA, Sonder I (2016) Recycling in debris-filled volcanic vents. Geology 44: 811-814, doi:10.1130/G38081.1

White JDL, Valentine GA (2016) Magmatic versus phreatomagmatic fragmentation: absence of evidence is not evidence of absence. Geosphere 12: 1478-1488, doi:10.1130/GES01337.1

Macorps É, Graettinger AH, Valentine GA, Ross P-S, White JDL, Sonder I (2016) The effects of host-substrate properties on maar-diatreme volcanoes: experimental evidence.  Bulletin of Volcanology 78:26, doi:10.1007/s00445-016-1013-8

Roche O, Buesch DC, Valentine GA (2016) Slow-moving, far-travelled dense pyroclastic flows during the Peach Spring super-eruption. Nature Communications 7: 10890, doi:10.1038/NCOMMS10890

Ball JL, Stauffer PJ, Calder ES, Valentine GA (2015) The hydrothermal alteration of cooling lava domes.  Bulletin of Volcanology 77:102, doi:10.1007/s00445-015-0986-z

Valentine GA, Sottili G, Palladino DM, Taddeucci J (2015) Tephra ring interpretation in light of evolving maar-diatreme concepts:  Stracciacappa maar (central Italy).  Journal of Volcanology and Geothermal Research 308: 19-29, doi:10.1016/j.jvolgeores.2015.10.010

Graettinger AH, Valentine GA, Sonder I (2015) Circum-crater variability of deposits from discrete, laterally and vertically migrating volcanic explosions: experimental evidence and field implications.  Journal of Volcanology and Geothermal Research 308:61-69, doi: 10.1016/j.jvolgeores.2015.10.019

Breard ECP, Lube G, Cronin SJ, Valentine GA (2015) Hydrothermal blast-produced pyroclastic density currents:  dynamics and deposition models.  Bulletin of Volcanology 77:100, doi:10.1007/s00445-015-0980-5

Sonder I, Graettinger AH, Valentine GA (2015) Scaling multiblast craters:  general approach and application to volcanic craters.  Journal of Geophysical Research 120, doi:10.1002/2015JB012018

Palladino DM, Valentine GA, Sottili G, Taddeucci J (2015) Maars to calderas:  end-members on a spectrum of explosive volcanic depressions.  Frontiers in Earth Science 3:36, doi: 10.3389/feart.2015.00036

Graettinger AH, Valentine GA, Sonder I, Ross P-S, White JDL (2015) Facies distribution of ejecta in analog tephra rings from experiments with single and multiple subsurface explosions.  Bulletin of Volcanology 77:66, doi:10.1007/s00445-015-0951-x

Valentine GA, Connor CB (2015) Basaltic volcanic fields.  In:  The Encyclopedia of Volcanoes, 2 Edition, H. Sigurdsson (ed.), Elsevier, 423-439, doi: 10.1016/B978-0-12-385938-9.00023-7

Sweeney MR, Valentine GA (2015) Transport and mixing dynamics from explosions in debris-filled volcanic conduits: Numerical results and implications for maar-diatreme volcanoes.  Earth and Planetary Science Letters 425: 64-76, doi:10.1016/j.epsl.2015.05.038

Harp AG, Valentine GA (2015) Shallow plumbing and eruptive processes of a scoria cone built on steep terrain.  Journal of Volcanology and Geothermal Research 294:37-55, doi:10.1016/j.jvolgeores.2015.02.008

Cortés JA, Smith EI, Valentine GA, Johnsen R, Rasoazanamparany C, Widom E, Sas M, Ruth D (2015) Intrinsic conditions of magmas from the Lunar Crater Volcanic Field (Nevada): Implications for internal plumbing and magma ascent.  American Mineralogist 100: 396-413, doi:10.2138/am-2015-4812

Valentine GA, Graettinger AH, Macorps E, Ross P-S, White JDL, Döhring E, Sonder I (2015) Experiments with vertically- and laterally-migrating subsurface explosions with applications to the geology of phreatomagmatic and hydrothermal explosion craters and diatremes. Bulletin of Volcanology 77:15, doi: 10.1007/s00445-015-0901-7

Rasoazanamparany C, Widom E, Valentine GA, Smith EI, Cortés JA, Kuentz D, Johnsen R (2015) Origin of chemical and isotopic heterogeneity in a mafic, monogenetic volcanic Field: a case study of the Lunar Crater Volcanic Field, Nevada.  Chemical Geology 397: 76-93, doi:10.1016/j.chemgeo.2015.01.004.

Tadini A, Bonali FL, Corazzato C, Cortés JA, Tibaldi A, Valentine GA (2014) Spatial distribution and structural analysis of vents in the Lunar Crater Volcanic Field (Nevada, USA).  Bulletin of Volcanology 76:877, doi:10.1007/s00445-014-0877-8

Johnson PJ, Valentine GA, Cortés JA, Tadini A (2014) Basaltic tephra from monogenetic Marcath Volcano, central Nevada. Journal of Volcanology and Geothermal Research 281: 27-33, doi: 10.1016/j.volgeores.2014.05.007

Valentine GA, Graettinger AH, Sonder I (2014) Explosion depths for phreatomagmatic eruptions.  Geophysical Research Letters 41: 3045-3051, doi: 10.1002/2014GL060096

Bowman DC, Taddeucci J, Kim K, Anderson JF, Lees JM, Graettinger AH, Sonder I, Valentine GA (2014) The acoustic signatures of ground acceleration, gas expansion, and spall fallback in experimental volcanic explosions.  Geophysical Research Letters 41: 1916-1922, doi:10.1002/2014GL059324

Graettinger AH, Valentine GA, Sonder I, Ross P-S, White JDL, Taddeucci J (2014) Maar-diatreme geometry and deposits:  subsurface blast experiments with variable explosion depth.  G – Geochemistry, Geophysics, Geosystems, doi: 10.1002/2013GC005198

Valentine GA, van Wyk de Vries B (2014) Unconventional maar-diatreme and associated intrusions in the soft sediment-hosted Mardoux structure (Gergovie, France).  Bulletin of Volcanology 76:807, doi: 10.1007/s00445-014-0807-9

Palma JL, Courtland L, Charbonnier S, Tortini R, Valentine GA (2014) Vhub:  a knowledge management system to facilitate online collaborative volcano modeling and research.  Journal of Applied Volcanology 3:2, doi: 10.1186/2191-5040-3-2

Roche O, Niño Y, Mangeney A, Brand B, Pollock N, Valentine GA (2013) Dynamic pore pressure variations induce substrate erosion by pyroclastic flows.  Geology 41:1107-1110, doi:10.1130/G34668.1

Valentine GA, Cortés JA (2013) Time and space variations in magmatic and phreatomagmatic eruptive processes at Easy Chair (Lunar Crater Volcanic Field, Nevada, USA).  Bulletin of Volcanology 75:752, doi:10.1007/s00445-013-0752-z.

Ross P-S, White JDL, Valentine GA, Taddeucci J, Sonder I, Andrews RG (2013) Experimental birth of a maar-diatreme volcano.  Journal of Volcanology and Geothermal Research 260: 1-12, doi:10.1016/j.jvolgeores.2013.05.005

Brown RJ, Valentine GA (2013) Physical characteristics of kimberlite and basaltic intraplate volcanism, and implications of a biased kimberlite record.  Geological Society of America Bulletin 125: 1224-1238, doi:10.1130/B30749.1

Taddeucci J, Valentine GA, Sonder I, White JDL, Ross P-S, Scarlato P (2013) The effect of pre-existing craters on the initial development of explosive volcanic eruptions:  an experimental investigation.  Geophysical Research Letters 40: 507-510, doi:10.1002/grl.50176

Valentine GA, White JDL (2012) Revised conceptual model for maar-diatremes: subsurface processes, energetics, and eruptive products. Geology 40:  1111-1114, doi:10.1130/G33411.1

Valentine GA, White JDL, Ross P-S, Amin J, Taddeucci J, Sonder I, Johnson PJ (2012) Experimental craters formed by single and multiple buried explosions and implications for volcanic craters with emphasis on maars.  Geophysical Research Letters 39, L20301, doi:10.1029/2012GL053716

Hintz AR, Valentine GA (2012) Complex plumbing of monogenetic scoria cones: New insights from the Lunar Crater Volcanic Field (Nevada, USA).  Journal of Volcanology and Geothermal Research 239-240: 19-32, doi:10.1016/j.jvolgeores.2012.06.008.

Valentine GA (2012) Shallow plumbing systems for small-volume basaltic volcanoes, 2:  Evidence from crustal xenoliths at scoria cones and maars.  Journal of Volcanology and Geothermal Research 223-224:  47-63, doi:10.1016/j.jvolgeores.2012.01.012