COMBINED ACTIVE AND PASSIVE SOURCE EXPERIMENT IN THE HIGH LAVA PLAINS
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The High Lava Plains Project in eastern Oregon is a multi-institutional, multi-disciplinary project to understand why the Pacific Northwest is the most volcanically active areas of the continental United States. A four-year deployment of 104 broadband PASSCAL instruments located at 118
sites observed hundreds of global and regional events that are being analyzed using a variety of techniques to study three-dimensional crustal and upper mantle structure, including thermal and compositional heterogeneity, as well as anisotropy to better understand the tectonic evolution of this complex region. An active-source experiment
using the entire PASSCAL and USArray inventory of ~3,000 Texan instruments recorded at 15 shot points is providing complementary high-resolution images of the crust. The
seismic results are currently being jointly interpreted with the results of geologic, geochemical, and petrolog-
ical studies to provide the first holistic model of tectonomagmatic evolution of the region. USArray magnetotelluric data are augmenting this effort.
Shown are maps of locations of broadband PASSCAL and TA stations(red squares) and active source reflection/refraction lines (black); an E-W cross section; and Moho depth. Details can be found in one-pagers
included in the Accomplishments volume. (Figure courtesy Kevin Eagar and Matt Fouch, Arizona State University)</p>