GPS vectors and surface tilt and uplift rates from northwestern Oregon and southwestern Washington are inverted to estimate rates of stress changes along the Cascadia thrust fault and base of the overriding plate using a finite thickness elastic plate model. The data are fit by elevated shear stress and Coulomb Failure Function (CFF) rates within 80 km of the trench. By contrast, an elastic half-space dislocation model does not fit as well and predicts significant amounts of locking and elevated CFF rates near the coast. ¿ 2001 American Geophysical Union