Volcanic risk, phreatomagmatic explosive eruptions, basaltic volcanic fields, pyroclastic deposits, volcano fluid dynamics, volcaniclastic and surface processes
PhD, Geological Sciences, University of California Santa Barbara – 1988
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.
Zarazúa-Carbajal MC, Valentine GA, De la Cruz-Reyna S (2024) Scoria cone erosional degradation by incision: different behaviors in three volcanic fields reflect environmental conditions. Geology 52:565-569, doi:10.1130/G52113.1
Valentine GA, (2023) Effects of debris entrainment and recycling on explosive volcanic eruption jets and columns. Bulletin of Volcanology 85:57, doi:10.1007/s00445-023-01675-8
Valentine GA, Fierstein J, White JDL (2022) Lateral extent of pyroclastic surge deposits at Ubehebe Crater (Death Valley, CA) and implications for hazards in monogenetic volcanic fields. Geophysical Research Letters, doi:10.1029/2022GL100561.
Valentine GA, Fierstein J, White JDL (2022) Pyroclastic deposits of Ubehebe Crater (Death Valley, California): ballistics, pyroclastic surges, and dry granular flows. Geosphere, doi:10.1130/GES02526.1
Sonder I, Graettinger A, Neilsen T, Matoza R, Taddeucci J, Oppenheimer J, Lev E, Tsunematsu K, Waite G, Valentine GA, Befus K (2022) Experimental multiblast craters and ejecta - seismo-acoustics, jet characteristics, craters, and ejecta deposits and implications for volcanic explosions. Journal of Geophysical Research Solid Earth, 127, e2022JB023952, doi:10.1029/2022JB023952
Valentine GA, Ort MH, Cortés JA (2021) Quaternary basaltic volcanic fields of the American Southwest. Geosphere, doi: 10.1130/GES02405.1
Valentine GA, Cole MA* (2021) Explosive caldera-forming eruptions and debris-filled vents: gargle dynamics. Geology 49:1240-1244, doi: 10.1130/G48995.1
Valentine GA, Fierstein J, White JDL (2021) Soft sediment deformation in dry pyroclastic deposits at Ubehebe Crater. Death Valley, California. Geology, doi:10.1130/G48147.1
Esposti Ongaro T, Cerminara M, Charbonnier SJ, Lube G, Valentine GA (2020) A framework for validation and benchmarking of pyroclastic current models. Bulletin of Volcanology 82:51
Moitra P, Sonder I, Valentine GA (2020) The role of external water on rapid cooling and fragmentation of magma. Earth and Planetary Sciences 537:116194, doi:10.1016/j.epsl.2020.116194
Valentine GA (2020) Initiation of dilute and concentrated pyroclastic currents from collapsing mixtures and origin of their proximal deposits. Bulletin of Volcanology 82:20, doi:10.1007/s00445-020-1366-x
Younger ZP, Valentine GA, Gregg TKP (2019) 'A'ā lava emplacement and the significance of rafted pyroclastic material: Marcath volcano (Nevada, USA). Bulletin of Volcanology 81:50, doi:10.1007/200445-019-1309-6
Valentine GA, Palladino DM, DiemKaye K, Fletcher C (2019) Lithic-rich and lithic-poor ignimbrites and their basal deposits: Sovana and Sorano formations (Latera caldera, Italy). Bulletin of Volcanology 81:29, doi:10.1007/s00445-019-1288-7
Valentine GA, Briner JP, van Wyk de Vries B, Macorps É, Gump D (2019) 10Be exposure ages for the Late Pleistocene Gour de Tazenat maar (Chaîne des Puys volcanic field, Auvergne, France). Quaternary Geochronology 50:8-13, doi:10.1016/j.quageo.2018.11.002
Sonder I, Harp AG, Graettinger AH, Moitra P, Valentine GA, Büttner R, Zimanowski B (2018) Meter-scale experiments on magma-water interaction. Journal of Geophysical Research Solid Earth 123, doi:10.1029/2018JB015682
Moitra P, Sonder I, Valentine GA (2018) Effects of size and temperature-dependent thermal conductivity on the cooling of pyroclasts in air. G3 – Geochemistry, Geophysics, Geosystems 19: doi: 10.1029/2018GC007510
Tierz P, Stefanescu ER, Sandri L, Sulpizio R, Valentine GA, Marzocchi W, Patra A (2018) Towards quantitative volcanic risk of pyroclastic density currents: probabilistic hazard curves and maps around Somma-Vesuvius (Italy). Journal of Geophysical Research Solid Earth 123:6299-6317, doi:10.1029/2017JB015383
Sweeney MR, Grosso Z, Valentine GA (2018) Topographic controls on a phreatomagmatic maar-diatreme eruption (Holocene Dotsero volcano, Colorado, USA): field and numerical results. Bulletin of Volcanology 80:78, doi:10.1007/s00445-018-1253-x
Johnson, PJ, Valentine GA, Stauffer PH, Lowry CS, Sonder I, Pulgarín CC, Agudelo A (2018) Groundwater drainage from fissures as a source for lahars. Bulletin of Volcanology 80:39, doi:10.1007/s00445-018-1214-4
Valentine GA, Sweeney MR (2018) Compressible flow phenomena at inception of lateral density currents fed by collapsing gas-particle mixtures. Journal of Geophysical Research Solid Earth 123, doi:10.1002/2017JB015129
Harp AG, Valentine GA (2018) Emplacement controls for the basaltic-andesitic radial dikes of Summer Coon volcano and implications for flank vents at stratovolcanoes. Bulletin of Volcanology 80: 16, doi:10.1007/s00445-018-1194-4
Graettinger AH, Valentine GA (2017) Evidence for the relative depths and energies of phreatomagmatic explosions recorded in tephra rings. Bulletin of Volcanology 79: 88, doi:10.1007/s00445-017-1177-x
Sweeney MR, Valentine GA (2017) Impact zone dynamics of dilute mono-and polydisperse jets and their implications for initial conditions of pyroclastic density currents. Physics of Fluids 29: 093304, doi:10.1063/1/5004197.
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