Portland is ill-prepared for the very likely 9.0 magnitude earthquake from the Cascadia subduction zone. In fact, we’re very badly/not at all prepared. It’s predicted all the city’s bridges (save one brand new one) would likely collapse. That on top the fact major regions of the city would be leveled due to being on fill dirt that would liquefy during such a quake.
This, however, is a good animation of what it would look like based on projections and engineering analysis of such earthquakes. Skip along to 1:37 for the animation.