3-D high-speed imaging of volcanic bomb trajectory in basaltic explosive eruptions

Geochemistry, Geophysics, Geosystems
By: , and 

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Abstract

Imaging, in general, and high speed imaging in particular are important emerging tools for the study of explosive volcanic eruptions. However, traditional 2-D video observations cannot measure volcanic ejecta motion toward and away from the camera, strongly hindering our capability to fully determine crucial hazard-related parameters such as explosion directionality and pyroclasts' absolute velocity. In this paper, we use up to three synchronized high-speed cameras to reconstruct pyroclasts trajectories in three dimensions. Classical stereographic techniques are adapted to overcome the difficult observation conditions of active volcanic vents, including the large number of overlapping pyroclasts which may change shape in flight, variable lighting and clouding conditions, and lack of direct access to the target. In particular, we use a laser rangefinder to measure the geometry of the filming setup and manually track pyroclasts on the videos. This method reduces uncertainties to 10° in azimuth and dip angle of the pyroclasts, and down to 20% in the absolute velocity estimation. We demonstrate the potential of this approach by three examples: the development of an explosion at Stromboli, a bubble burst at Halema'uma'u lava lake, and an in-flight collision between two bombs at Stromboli.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title 3-D high-speed imaging of volcanic bomb trajectory in basaltic explosive eruptions
Series title Geochemistry, Geophysics, Geosystems
DOI 10.1002/2016GC006560
Volume 17
Issue 10
Year Published 2016
Language English
Publisher American Geophysical Union
Contributing office(s) Volcano Science Center
Description 8 p.
First page 4268
Last page 4275