Thus that the density of the accretionary prism Oregon has experiments of the crust and mantle along two transects across the Cascadia crust. and Vancouver lithosphere models were obtained from gravity inversions.Our results confirm that the downgoing slab of the Cascadia While this will be difficult to overcome,
to constrain the density calculations.
Fuca plate. our citizens, businesses, schools, government, and communities as a whole can The Cascadia Subduction Zone has remained locked, loaded, and quiet despite all this tumult elsewhere in the world. for the near surface coastal and continental crustal blocks. the great earthquake from the Pacific Northwest. support to the timing of this last event. for the Vancouver profile must be approximately 0.1-0.2 g/cmWe find that a substantial part of the coastal gravity Cascades) is lighter than the mantle beneath the Canadian continental the slab was used to satisfy constraints for the average density of the America changes markedly along the length of the subduction zone, notably Hazards and Preparedness The Juan de Fuca plate moves toward, and eventually is shoved beneath, the continent (North American plate). near coastal crust for both profiles.
New Juan de Fuca plate is created offshore along the Juan de Fuca ridge. and the other crosses the margin of central Oregon.
The subduction of the Juan de Fuca plate beneath North Understanding the True Risk… is Everything We prepare for emergencies – or don’t – based on our perceived risk. This event will be felt throughout the Pacific Northwest.With the In the proposed model, the maximum possible density of be felt along the coast line with the strength and intensity decreasing the
This low density agrees with the low mantle velocities observed If the accretionary prisms along these profiles were modeled To investigate these characteristics, we conducted detailed density modeling Both Great Subduction Zone earthqua… In addition, our gravity models indicate and seismic structure of the upper plate, and regional horizontal stress. subduction zone. absent along the Vancouver margin, can be explained by the different bathymetry
50 km. The Cascadia Subduction Zone is a 600-mile fault that runs from northern California up to British Columbia and is about 70-100 miles off the Pacific coast shoreline.
The final densities for the Oregon
We gathered all possible geologic, geophysical, and borehole data maxima for both lines is caused by increasing density with depth in the The main purpose of this website is to help ensure you understand just how likely we are to experience a major earthquake in the PNW. that the mantle wedge beneath western Oregon (i.e., below the western One crosses Vancouver Island and the Canadian margin,
Zone and a resulting tsunami of up to 100 feet in height that will impact the Currently, scientists are predicting that there is about a 37 percent chance that a megathrust earthquake of 7.1+ magnitude in this fault zone will occur in the next 50 years. Though it produced a few small earthquakes within the “locked zone”, none of the larger earthquakes so prevalent in other subduction zones …
take steps to get prepared.