Interseismic locking of the plate interface in the northern Cascadia subduction zone, inferred from inversion of GPS data

We inverted GPS velocities from 20 continuous and 53 campaign sites in the northern Cascadia subduction zone using a Bayesian inverse method to estimate the locking state of the plate interface. The results are consistent with previous estimates based on thermal arguments and forward modeling. They suggest that the completely locked segment of the plate interface is offshore and that the degree of locking gradually decreases landward. The very gradual transition from full locking to full slip approximates the effect of stress relaxation that is not included by the elastic model assumed for the inversion.