Modeling ash fall distribution from a Yellowstone supereruption

Geochemistry, Geophysics, Geosystems
By: , and 

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Abstract

We used the volcanic ash transport and dispersion model Ash3d to estimate the distribution of ashfall that would result from a modern-day Plinian supereruption at Yellowstone volcano. The simulations required modifying Ash3d to consider growth of a continent-scale umbrella cloud and its interaction with ambient wind fields. We simulated eruptions lasting 3 days, 1 week, and 1 month, each producing 330 km3 of volcanic ash, dense-rock equivalent (DRE). Results demonstrate that radial expansion of the umbrella cloud is capable of driving ash upwind (westward) and crosswind (N-S) in excess of 1500 km, producing more-or-less radially symmetric isopachs that are only secondarily modified by ambient wind. Deposit thicknesses are decimeters to meters in the northern Rocky Mountains, centimeters to decimeters in the northern Midwest, and millimeters to centimeters on the East, West, and Gulf Coasts. Umbrella cloud growth may explain the extremely widespread dispersal of the ∼640 ka and 2.1 Ma Yellowstone tephra deposits in the eastern Pacific, northeastern California, southern California, and South Texas.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Modeling ash fall distribution from a Yellowstone supereruption
Series title Geochemistry, Geophysics, Geosystems
DOI 10.1002/2014GC005469
Volume 15
Issue 8
Year Published 2014
Language English
Publisher American Geophysical Union
Contributing office(s) Volcano Hazards Program, Volcano Science Center
Description 17 p.
First page 3459
Last page 3475
Country United States
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