Journal
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
Volume 203, Issue 3-4, Pages 168-174Publisher
ELSEVIER
DOI: 10.1016/j.jvolgeores.2011.04.006
Keywords
magma porosity; porosity distribution histogram; eruption styles; Volcanic Explosivity Index; field density measurements
Categories
Funding
- German Ministry of Education and Research (BMBF) [GEOTECH-1528]
- German Research Foundation (DFG) [PTJ MGS/03G584A-SUNDAARC-DEVACOM]
- NERC [NE/G014426/1] Funding Source: UKRI
- Natural Environment Research Council [NE/G014426/1] Funding Source: researchfish
Ask authors/readers for more resources
The porosity of pyroclasts is a valuable indicator of the character of a volcanic eruption. Here, we analyse the porosity distribution of deposits of 17 different volcanic eruptions, covering a broad range of inferred magma properties and observed eruption styles. Histograms of porosity versus pyroclast frequency show distinctive features in terms of the mean, variance, modality, and skewness. We present characteristic porosity distributions for five different eruption-style categories: dome-forming, explosive basaltic, cryptodome forming, Subplinian/Plinian/Ultraplinian, and phreatomagmatic. We find that the mean porosity values of the deposits correlate positively with the Volcanic Explosivity Index (VEI) of Newhall and Self (1982), regardless of the degree of complexity of the individual distributions. We then propose causes of the deviations from a general trend in terms of magma viscosity, degassing efficiency, and cap-rock confinement. Finally, a generalised correlation between clast porosity and explosivity of an eruption is developed that should help, together with conventional field techniques, facilitate the interpretation of pyroclastic sequences, even in cases where no direct observation of the eruption exists. (C) 2011 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available