Experimental investigations on the explosivity of steam‐driven eruptions: A case study of Solfatara volcano (Campi Flegrei)

Autor: Donald B. Dingwell, Klaus F. X. Mayer, Roberto Moretti, Roberto Isaia, Cristian Montanaro, Giovanni Orsi, Bettina Scheu
Přispěvatelé: Montanaro, Cristian, Scheu, Bettina, Mayer, Klau, Orsi, Giovanni, Moretti, Roberto, Isaia, Roberto, Dingwell, Donald B.
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Work (thermodynamics)
Atmospheric Science
explosive energy
010504 meteorology & atmospheric sciences
experimental
liquid fraction
steam‐driven eruptions
Volcanic explosivity index
Hydrothermal Systems
010502 geochemistry & geophysics
Oceanography
Biogeosciences
01 natural sciences
steam-driven eruption
Oceanography: Biological and Chemical
Earth and Planetary Sciences (miscellaneous)
Phreatic
Experimental Volcanism
Research Articles
Water Science and Technology
geography.geographical_feature_category
Ecology
food and beverages
Forestry
Marine Geology and Geophysics
Geophysics
Explosive Volcanism
Thermodynamics
Cryosphere
Geology
Research Article
Explosive material
Mineralogy
chemistry.chemical_element
Soil Science
Volcanology
Aquatic Science
Geochemistry and Petrology
Caldera
Solfatara
Geophysic
0105 earth and related environmental sciences
Mineralogy and Petrology
geography
Argon
Geological
Paleontology
Flashing
Geochemistry
Tectonophysics
chemistry
Volcano
13. Climate action
Space and Planetary Science
Earth-Surface Processe
Chemistry and Physics of Minerals and Rocks/Volcanology
Natural Hazards
petrophysical
Zdroj: Journal of Geophysical Research. Solid Earth
ISSN: 2169-9356
2169-9313
Popis: Steam‐driven eruptions, both phreatic and hydrothermal, expel exclusively fragments of non‐juvenile rocks disintegrated by the expansion of water as liquid or gas phase. As their violence is related to the magnitude of the decompression work that can be performed by fluid expansion, these eruptions may occur with variable degrees of explosivity. In this study we investigate the influence of liquid fraction and rock petrophysical properties on the steam‐driven explosive energy. A series of fine‐grained heterogeneous tuffs from the Campi Flegrei caldera were investigated for their petrophysical properties. The rapid depressurization of various amounts of liquid water within the rock pore space can yield highly variable fragmentation and ejection behaviors for the investigated tuffs. Our results suggest that the pore liquid fraction controls the stored explosive energy with an increasing liquid fraction within the pore space increasing the explosive energy. Overall, the energy released by steam flashing can be estimated to be 1 order of magnitude higher than for simple (Argon) gas expansion and may produce a higher amount of fine material even under partially saturated conditions. The energy surplus in the presence of steam flashing leads to a faster fragmentation with respect to gas expansion and to higher ejection velocities imparted to the fragmented particles. Moreover, weak and low permeability rocks yield a maximum fine fraction. Using experiments to unravel the energetics of steam‐driven eruptions has yielded estimates for several parameters controlling their explosivity. These findings should be considered for both modeling and evaluation of the hazards associated with steam‐driven eruptions.
Key Points Experimental studies to unravel the steam‐driven eruption energeticsInfluence of liquid fraction and rock petrophysical properties on the explosive energySteam flashing results in a faster fragmentation with respect to gas expansion and into higher ejection velocities of fragmented material
Databáze: OpenAIRE
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