People don't prepare for events that happen every 300 years. Even if every building in Portland (and Oregon) were built and/or retrofitted to the strictest codes there are to supposedly survive an earthquake, the reality is if and when the big one hits it is going to destroy all of the infrastructure (roads, bridges, utilities, etc.).

There is no way to prevent the mass destruction that will occur and people, no matter how well they may or may not have prepared, are not able to comprehend what it will be like when it occurs.

I live on the coast in the tsunami zone. Renters' insurance does not cover floods either. The town I live in will be wiped off the face of the earth if and when the big one hits. The city talks a lot about shoring up bridges so people can get to higher ground and they're building a brand new school facility on that higher ground which would be the place people will run to in order to try to survive the tsunami. But there is no guarantee that facility would even survive a 9.0 earthquake, then what?

Each individual has to make a decision about what kind of risk they are willing to live with and whether it is worth it to them. My mom (nearly 70) and me (disabled) know full well that we don't even remotely stand a chance of surviving in the event of a catastrophic earthquake and tsunami here. Given her age and my illness and the odds (could happen in the next 30 years or 50 years or ?) we choose to live here and have made our peace with it. I think anyone living in the Cascadia Zone (or whatever they call it) has done or has to do the same.