thumbnail

Improved constraints on the estimated size and volatile content of the Mount St. Helens magma system from the 2004-2008 history of dome growth and deformation

Geophysical Research Letters

By:
, , , and

Links

Abstract

The history of dome growth and geodetic deflation during the 2004-2008 Mount St. Helens eruption can be fit to theoretical curves with parameters such as reservoir volume, bubble content, initial overpressure, and magma rheology, here assumed to be Newtonian viscous, with or without a solid plug in the conduit center. Data from 2004-2008 are consistent with eruption from a 10-25 km3 reservoir containing 0.5-2% bubbles, an initial overpressure of 10-20 MPa, and no significant, sustained recharge. During the eruption we used curve fits to project the eruption's final duration and volume. Early projections predicted a final volume only about half of the actual value; but projections increased with each measurement, implying a temporal increase in reservoir volume or compressibility. A simple interpretation is that early effusion was driven by a 5-10 km3, integrated core of fluid magma. This core expanded with time through creep of semi-solid magma and host rock.

Study Area

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Improved constraints on the estimated size and volatile content of the Mount St. Helens magma system from the 2004-2008 history of dome growth and deformation
Series title:
Geophysical Research Letters
Volume
36
Issue:
20
Year Published:
2009
Language:
English
Publisher:
American Geophysical Union
Publisher location:
Washington D.C.
Contributing office(s):
Volcano Science Center
Description:
4 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geophysical Research Letters
First page:
1
Last page:
4
Country:
United States
State:
Washington
Other Geospatial:
Mount St. Helens