Magma fragmentation in highly explosive basaltic eruptions induced by rapid crystallization
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
Basaltic eruptions are the most common form of volcanism on Earth and planetary bodies. The low viscosity of basaltic magmas inhibits fragmentation, which favours effusive and lava-fountaining activity, yet highly explosive, hazardous basaltic eruptions occur. The processes that promote fragmentation of basaltic magma remain unclear and are subject to debate. Here we used a numerical conduit model to show that a rapid magma ascent during explosive eruptions produces a large undercooling. In situ experiments revealed that undercooling drives exceptionally rapid (in minutes) crystallization, which induces a step change in viscosity that triggers magma fragmentation. The experimentally produced textures are consistent with basaltic Plinian eruption products. We applied a numerical model to investigate basaltic magma fragmentation over a wide parameter space and found that all basaltic volcanoes have the potential to produce highly explosive eruptions. The critical requirements are initial magma temperatures lower than 1,100 °C to reach a syn-eruptive crystal content of over 30 vol%, and thus a magma viscosity around 105 Pa s, which our results suggest is the minimum viscosity required for the fragmentation of fast ascending basaltic magmas. These temperature, crystal content and viscosity requirements reveal how typically effusive basaltic volcanoes can produce unexpected highly explosive and hazardous eruptions.
Date Issued
2019-12-01
Date Acceptance
2019-09-10
Citation
Nature Geoscience, 2019, 12 (12), pp.1023-1028
ISSN
1752-0894
Publisher
Nature Research
Start Page
1023
End Page
1028
Journal / Book Title
Nature Geoscience
Volume
12
Issue
12
Copyright Statement
© The Author(s), under exclusive licence to Springer Nature Limited 2019. The final publication is available at Springer via https://doi.org/10.1038/s41561-019-0468-6
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000499653700014&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Geosciences, Multidisciplinary
Geology
PLINIAN ERUPTION
VOLCANIC-ERUPTIONS
ETNA
STROMBOLI
KINETICS
ASCENT
VISCOSITY
CONSTRAINTS
STYLE
MORPHOLOGIES
Publication Status
Published
Date Publish Online
2019-10-21