A Survey of Ant Species in Three Habitats at Mount St. Helens National Volcanic Monument

Dynamics of seismogenic volcanic extrusion , Mount St . Helens , 2004 - 2005

behaviour characterized by nearly steady extrusion of a solid dacite plug and nearly periodic shallow earthquakes. Diverse data motivate the hypothesis that these earthquakes resulted from stick-slip motion along the margins of the plug as it was forced incrementally upward by ascending, solidifying, gas-poor magma. We formalize this hypothesis with a dynamical model that reveals a strong analo...

Scattering matrices of volcanic ash particles of Mount St. Helens, Redoubt, and Mount Spurr Volcanoes

[1] We present measurements of the whole scattering matrix as a function of the scattering angle at a wavelength of 632.8 nm in the scattering angle range 3 –174 of randomly oriented particles taken from seven samples of volcanic ashes corresponding to four different volcanic eruptions: the 18 May 1980 Mount St. Helens eruption, the 1989–1990 Redoubt eruption, and the 18 August and 17 September...

Petrogenesis of Mount St. Helens Dacitic Magmas

The most frequent and voluminous eruptive Kurasawa, 1983], (4) partial melting of the lower crust products at Mount St. Helens are dacitic in composition, [e.g., Grant et al., 1984; Reid and Cole, 1983], and (5) although a wide variety of magma types (basalt to formation of compositional gradients in response to rhyodacite) is represented. To address the petrogenesis of convective and diffusive...

The origin of Mount St. Helens andesites

Smith, D. R. and Leeman, W. P., 1993. The origin of Mount St. Helens andesites. J. Volcanol. Geotherm. Res., 55: 271-303. Mount St. Helens volcano has intermittently produced mainly dacitic products but occasionally erupted a more diverse suite of lavas including basalts and andesites. Petrogenetic relations between these magmas provide insight into the dynamics of the subjacent magma system. M...

Measurements of the volcanic plumes of mount st. Helens in the stratosphere and troposphere: introduction.