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High-speed imaging of Strombolian explosions: The ejection velocity of pyroclasts
Author(s)
Language
English
Obiettivo Specifico
3V. Dinamiche e scenari eruttivi
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
/39 (2012)
ISSN
0094-8276
Electronic ISSN
1944-8007
Publisher
American Geophysical Union
Pages (printed)
L02301
Issued date
January 18, 2012
Alternative Location
Subjects
Abstract
Explosive volcanic eruptions are defined as the violent ejection of gas and hot fragments from a vent in the Earth's crust. Knowledge of ejection velocity is crucial for understanding and modeling relevant physical processes of an eruption, and yet direct measurements are still a difficult task with largely variable results. Here we apply pioneering high-speed imaging to measure the ejection velocity of pyroclasts from Strombolian explosive eruptions with an unparalleled temporal resolution. Measured supersonic velocities, up to 405 m/s, are twice higher than previously reported for such eruptions. Individual Strombolian explosions include multiple, sub-second-lasting ejection pulses characterized by an exponential decay of velocity. When fitted with an empirical model from shock-tube experiments literature, this decay allows constraining the length of the pressurized gas pockets responsible for the ejection pulses. These results directly impact eruption modeling and related hazard assessment, as well as the interpretation of geophysical signals from monitoring networks.
Sponsors
INGV-DPC “V2” and “Paroxysm”, FIRB-MIUR “Research and Development of New Technologies for Protection and Defense of Territory from Natural Risks”, and FP7-PEOPLE-IEF-2008 – 235328 Projects
Type
article
File(s)
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Name
2011GL050404.pdf
Description
Main article
Size
1.67 MB
Format
Adobe PDF
Checksum (MD5)
697ef023d7b218013920034fa0b5c320