University of Illinois Urbana-Champaign

Volcan Reventador's unusual umbrella

Chakraborty, Pinaki; Gioia, Gustavo; Kieffer, Susan

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https://hdl.handle.net/2142/330

Description

Title
Volcan Reventador's unusual umbrella
Author(s)
  • Chakraborty, Pinaki
  • Gioia, Gustavo
  • Kieffer, Susan
Issue Date
2005-09
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.
Publisher
Department of Theoretical and Applied Mechanics (UIUC)
Series/Report Name or Number
TAM Reports 1072, (2005)
ISSN
0073-5264
Type of Resource
text
Language
en
Permalink
http://hdl.handle.net/2142/330

Owning Collections

Technical Reports - Theoretical and Applied Mechanics (TAM) PRIMARY
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.