Remove Sandy River from Bird model

[pmpowers-usgs]

Peter Birds geodetic model assigns the Sandy River fault near Portland a very high rate, relative to the geologic model, and was included in a broad deformation zone modeled with gridded seismicity sources with equivalent moment rate to the faults in the zone. It should therefore not have a finite representation in the model.

Need to confirm that the Peter Bird faults were supposed to be removed entirely or just have their slip rate halved.

[pmpowers-usgs]

Removed in f8bfc78