The project will initiate seafloor geodetic measurements of plate motion in the Cascadia Subduction Zone. The proposal is for a three-year effort to measure plate motion at three sites along an East-West profile at latitude 44.6â—¦ N, offshore Newport Oregon. One site will be located on the incoming plate to measure the present day convergence between the Juan de Fuca and North American plates and two additional sites will be located on the continental slope of NA to measure the elastic deformation due to stick-slip behavior on the megathrust fault. These new seafloor data will constrain existing models of slip behavior that presently are poorly constrained by land geodetic data 100 km from the deformation front.
We will implement for the first time a new autonomous approach to collecting GPS-Acoustic data that will greatly reduce the cost of data collection by no longer relying upon research ships. Similarly, for the first time, permanent seafloor benchmarks for horizontal positioning will be implemented ensuring the time series of positions can be continued into the future.
Study results should better quantify the earthquake and tsunami risk associated with a large rupture of the thrust fault within the Cascadia subduction zone.