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Experiments on deaerating granular flows and implications for pyroclastic flow mobility
Author(s) -
Roche O.,
Gilbertson M.,
Phillips J. C.,
Sparks R. S. J.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl014819
Subject(s) - pyroclastic rock , fluidization , flow (mathematics) , geology , volume (thermodynamics) , mechanics , granular material , fluidized bed , materials science , geotechnical engineering , thermodynamics , physics , geochemistry , volcano
Granular flows were generated by the release of beds of particles in various fluidized states, which then deaerated in a horizontal channel. We describe characteristics of the flows and their deposits. Morphological similarities between deposits in experiments and in the field suggest that pyroclastic flow deposits form from a fluidized mixture. The experiments show that slightly expanded, fluidized flows are more mobile than non‐fluidized flows of equivalent volume and material composition. They travel to a fixed distance from their source, which depends only weakly on their initial degree of fluidization. Flows of fine particles (<100 μm) deaerate slowly and are highly mobile. Pyroclastic flows commonly have large amounts of fine ash, which may have a controlling influence on their high mobility.