IRIS and the USGS released a video last summer about how the various faults interact in the Pacific Northwest region, including the Juan de Fuca plate, the Cascadia Subduction Zone, the San Andreas fault, as well as the deeper and shallower faults in Oregon and Washington. If you’re interested in the complexity of the seismic risk to the Pacific Northwest, this video is definitely a worth a few minutes to watch and get a better understanding of the whole picture.