I am absolutely certain you are mis-remembering, or the popsci distorted the engineering in their efforts to make it interesting for public consumption. I attend a lot of disaster conferences. I sat in on a policy session at the rock mechanics conference in Vancouver in the fall of 2007? 2008? where at least 100 global experts gathered specifically to discuss earthquake building codes in subduction zones (including the PNW and Japan). Low-frequency, low-intensity earthquake zones have lax codes, yes, but low-frequency high-intensity zones currently have very, very strong codes that at this point are only revised upwards to be more strong. (The iconic image of the Japanese low-rises toppling over prompted a set of revisions for building on sediment.)
Again, not a chance that's an accurate geotechnical assessment of any urban center in Canada or the United States. In part this is because our assessments have more to do with the hypocenter (the actual location of rupture) than the epicenter (the surface projection of the hypocenter). In California, the two are often close-enough to being the same, but in subduction zones the depth of the hypocenter has a huge impact on the type of shaking that will be felt. As I've explained in other comments in this thread, the PNW can get shallower magnitude 7 earthquakes that will cause a devastating amount of surface shaking in a very small area, or deeper magnitude 9 earthquakes that will cause less severe surface shaking over a very wide area. It is geologically not possible to have severe surface shaking over a large region*.
* This is true globally, unless you have local superficial geology that intensifies shaking. Mexico City is located in a sediment-filled basin that amplifies ANY surface waves that go anywhere nearby.