HR: 16:45h
AN: V24B-04    [Abstracts]
TI: Mount Pinatubo's starfish umbrella plume
AU: * Chakraborty, P
EM: chakrabo@uiuc.edu
AF: University of Illinois, Department of Geology, 1301 W. Green St, Urbana, IL 61801, United States
AU: Kieffer, S W
EM: skieffer@uiuc.edu
AF: University of Illinois, Department of Geology, 1301 W. Green St, Urbana, IL 61801, United States
AU: Gioia, G
EM: ggioia@uiuc.edu
AF: University of Illinois, Department of Mechanical Science and Engineering, 1206 W. Green St, Urbana, IL 61801, United States
AB: Satellite images of the umbrella plume that topped the column of Mount Pinatubo's climactic eruption of June 15, 1991, reveal that in the course of expanding radially the edge of the umbrella plume became wavy, so that in plan view the umbrella plume took the shape of a starfish. Simultaneous with this development, tropical typhoon Yunya made a close approach to Mount Pinatubo. Here we propose that the starfish-shaped umbrella plume was induced by typhoon Yunya. In this scenario the umbrella plume, originally circular in plan view, was centrifuged out of its axis by the typhoon. The attendant centrifugal forces triggered a turbulent variant of the Rayleigh--Taylor instability of the same wavelength as the observed starfish-shaped umbrella plume.
DE: 3215 Instability analysis
DE: 3379 Turbulence (4490)
DE: 8400 VOLCANOLOGY
DE: 8409 Atmospheric effects (0370)
DE: 8428 Explosive volcanism
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting