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Title:Volcan Reventador's unusual umbrella
Author(s):Chakraborty, Pinaki; Gioia, Gustavo; Kieffer, Susan
Abstract:Photographs of a volcanic column in a recent eruption of Reventador show a prominently scalloped umbrella that is unlike any umbrella previously documented on a volcanic column. We propose that the scallops in this umbrella are the result of a turbulent RayleighTaylor instability with no precedents in volcanology. We ascribe the rare negative buoyancy that drives this instability to the fact that the Reventador column fed on a cool co-ignimbrite cloud. From the wavelength of the scallops, we estimate a value for the eddy viscosity of the umbrella, the first such value to be inferred directly from an observation in the field, and show that this value is consistent with a lower bound obtained previously by a disparate method. Last, we discuss the implications of our results for volcanic eruption dynamics and hazards. We hope this work will prompt and guide the documentation of other scalloped umbrellas.
Issue Date:2005-09
Publisher:Department of Theoretical and Applied Mechanics (UIUC)
Series/Report:TAM Reports 1072, (2005)
Genre:Technical Report
Publication Status:published or submitted for publication
Peer Reviewed:is peer reviewed
Date Available in IDEALS:2007-03-09
Is Version Of:Published as: Pinaki Chakraborty, Gustavo Gioia and Susan Kieffer. Volcan Reventador's unusual umbrella. Geophysical Research Letters. Vol. 33, no. 5, pp. L05313. DOI: 10.1029/2005GL024915. Copyright 2006 American Geophysical Union.

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  • Technical Reports - Theoretical and Applied Mechanics (TAM)
    TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.

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