Title: A Model for Dome Eruptions at Mount St. Helens, Washington Based on Subcritical Crack Growth
Abstract: A model that idealizes the Mt. St. Helens lava dome as a brittle shell enclosing a pressurized, ductile interior (Iverson, this Vol.) is utilized here to interpret accelerating deformation during episodic dome growth. This approach assumes that the brittle exterior of the dome represents the most significant obstacle to lava extrusion, and that lava extrusion begins when the shell ruptures. With this model, the accelerating growth of the dome prior to each extrusion in 1981 and 1982 may be interpreted to be due either to a nonlinear increase in pressure within the dome with time or to slow crack growth that progressively weakens the domes’ brittle shell. Comparison with the deformation data for the May 14, 1982, extrusion suggests that slow crack growth within the dome is the most likely factor contributing to the deformation. If this conclusion is supported by future studies, then the increase in the likelihood of an eruption with increasing time between eruptions may be calculated based upon the rate of pressurization of the dome and the crack growth characteristics of its brittle exterior.
Publication Year: 1990
Publication Date: 1990-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 17
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