Brodsky, Emily E. and Kanamori, Hiroo and Sturtevant, Bradford
(1999)
A seismically constrained mass discharge rate for the initiation of the May 18, 1980 Mount St. Helens eruption.
Journal of Geophysical Research B, 104
(B12).
pp. 29387-29400.
ISSN 2169-9313.
doi:10.1029/1999JB900308.
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Abstract
We calculate the vertical mass discharge rate from Mount St. Helens for the first few minutes of the May 18, 1980 cataclysmic eruption using a new method based on seismic constraints. The observed seismic waves indicate that the seismic source is a series of single forces. We model these forces as thrusts due to a combination of the momentum flux of the erupted products and the pressure of the eruptive jet. The momentum discharge rate is converted to a mass discharge rate based on estimates of the velocity and jet pressure as constrained by a simple fluid dynamical model. Only two parameters are necessary for the calculation: Mach number and sound velocity. The calculated mass ejected in the first 100 s is 1.6×10^(11) −4.6×10^(11) kg. Since the total blast deposit is ∼3.2×10(^11) − 4.1×10^(11) kg, one possible interpretation is that the directed blast had a significant (>30%) vertical component.
Item Type: | Article |
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Additional Information: | © 1999 The American Geophysical Union.
Paper number 1999JB900308.
Received January 5, 1999; Revised July 22, 1999; Accepted September 7, 1999.
Correspondence and conversations
with S. Kieffer, S. Malone, R. Waitt and R. Hoblitt have
been valuable in understanding the geological and observational
records. This paper is based on work supported under
the National Science Foundation grant EAR-9903085 and is
contribution 8678 of the Division of Geological and Planetary
Sciences, California Institute of Technology. |
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Funders: | Funding Agency | Grant Number |
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NSF | EAR-9903085 |
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Other Numbering System: | Other Numbering System Name | Other Numbering System ID |
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Caltech Division of Geological and Planetary Sciences | 8678 |
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Issue or Number: | B12 |
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DOI: | 10.1029/1999JB900308 |
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Record Number: | CaltechAUTHORS:20141031-120101243 |
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Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20141031-120101243 |
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Official Citation: | Brodsky, E. E., Kanamori, H., & Sturtevant, B. (1999). A seismically constrained mass discharge rate for the initiation of the May 18, 1980 Mount St. Helens eruption. Journal of Geophysical Research: Solid Earth, 104(B12), 29387-29400. doi: 10.1029/1999jb900308 |
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Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. |
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ID Code: | 51123 |
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Collection: | CaltechAUTHORS |
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Deposited By: | INVALID USER |
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Deposited On: | 31 Oct 2014 19:59 |
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Last Modified: | 10 Nov 2021 19:06 |
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