Morphology and rheology of pyroclastic (of Mount St. Helens) flows and their deposits and guidelines for future observations

Wilson, L. and Head, J. W. (1981) Morphology and rheology of pyroclastic (of Mount St. Helens) flows and their deposits and guidelines for future observations. U.S. Geological Survey Professional Paper, 1250. pp. 513-524.

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Abstract

Morphological and rheological measurements were made on some of the deposits of the pyroclastic flows of July 22 and August 7. Evidence indicates that the flows moved as non-Newtonian fluids most readily modeled as Bingham fluids. Values are given for yield strengths of the flows: at the time of emplacement, after a few days, and after a few weeks. Average values are about 600, 1500 and 10 000 N/m2, respectively. Extensive reverse grading of coarse, low-density pumice clasts in the levee deposits was the result of interaction between the flow and the atmosphere, which increased the degree of fluidization of the levees at the time of their emplacement.-from Authors

Item Type:
Journal Article
Journal or Publication Title:
U.S. Geological Survey Professional Paper
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1907
Subjects:
ID Code:
149055
Deposited By:
Deposited On:
16 Nov 2020 14:30
Refereed?:
Yes
Published?:
Published
Last Modified:
23 Nov 2020 14:56