Collaborative Research: Imaging plate boundary processes within the Cascadia subduction zone offshore central Washington with open-access marine seismic data

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Analysis of recently acquired multi-channel seismic (MCS) data will address a series of topics that relate to the structure of the lithosphere and margin evolution along the central WA portion of Cascadia subduction zone and how these relate to current seismicity patterns. Advanced processing of the ~1100 km grid of MCS data is expected to identify the depth and character of the plate boundary and the amount of sediment currently being subducted will be assessed. Deformation of strata within the accretionary wedge will be mapped to track longer-term evolution of the plate interactions. Estimates of crustal hydration will be obtained from assumed seismic velocity - porosity relationships and, along interfaces, reflectivity. Maps showing the distribution of methane hydrates in the region will be produced.Results will provide a framework within which other Cascadia geoscience studies are conducted, both for seismic processes and tectonic evolution, and are likely to have implications for hazard assessment. While this subduction zone currently has less earthquake activity than other zones around the world, onshore evidence of repeated megathrust events is clear over times scales of hundreds of years, so it is important to understand the history of stress buildup (strata deformation) and the extent to which fluids along faults might enable periods of 'lubricated', slow stress release.