<> "The repository administrator has not yet configured an RDF license."^^ . <> . . . "Eruption dynamics at Mount St. Helens imaged from broadband seismic waveforms: Interaction of the shallow magmatic and hydrothermal systems"^^ . "The current eruption at Mount St. Helens is characterized by dome building and shallow, repetitive, long-period (LP) earthquakes. Waveform cross-correlation reveals remarkable similarity for a majority of the earthquakes over periods of several weeks. Stacked spectra of these events display multiple peaks between 0.5 and 2 Hz that are common to most stations. Lower-amplitude very-long-period (VLP) events commonly accompany the LP events. We model the source mechanisms of LP and VLP events in the 0.5–4 s and 8–40 s bands, respectively, using data recorded in July 2005 with a 19-station temporary broadband network. The source mechanism of the LP events includes: 1) a volumetric component modeled as resonance of a gently NNW-dipping, steam-filled crack located directly beneath the actively extruding part of the new dome and within 100 m of the crater floor and 2) a vertical single force attributed to movement of the overlying dome. The VLP source, which also includes volumetric and single-force components, is 250 m deeper and NNW of the LP source, at the SW edge of the 1980s lava dome. The volumetric component points to the compression and expansion of a shallow, magma-filled sill, which is subparallel to the hydrothermal crack imaged at the LP source, coupled with a smaller component of expansion and compression of a dike. The single-force components are due to mass advection in the magma conduit. The location, geometry and timing of the sources suggest the VLP and LP events are caused by perturbations of a common crack system."^^ . "2008-02" . . "113" . "B2" . . "American Geophysical Union"^^ . . . "Journal of Geophysical Research"^^ . . . "01480227" . . . . . . . . . . . "Gregory P."^^ . "Waite"^^ . "Gregory P. Waite"^^ . . "Bernard A."^^ . "Chouet"^^ . "Bernard A. Chouet"^^ . . "Phillip B."^^ . "Dawson"^^ . "Phillip B. Dawson"^^ . . "U.S. Geological Survey, Volcano Hazards, Menlo Park, California, USA Now at Geol. & Mining Eng. & Sci., Michigan Technological University, Houghton, Michigan, USA."^^ . . . "U.S. Geological Survey, Volcano Hazards, Menlo Park, California, USA"^^ . . . "U.S. Geological Survey, Volcano Hazards, Menlo Park, California, USA"^^ . . . . . . "HTML Summary of #1738 \n\nEruption dynamics at Mount St. Helens imaged from broadband seismic waveforms: Interaction of the shallow magmatic and hydrothermal systems\n\n" . "text/html" . . . "Other-additional study" . . . "USA" . . . "Method and procesing" . .