There have been seven large Cascadia subduction zone earthquakes in the last 3500 yrs or so. About a 500 year repeat interval. The last one was in precisely 170

There have been seven large Cascadia subduction zone earthquakes in the last 3500 yrs or so. About a 500 year repeat interval. The last one was in precisely 1700, known from historical records. So, on average, the next one would be in 200 yrs (but could come tomorrow or even further into the future). Building new construction to survive such a quake is probably a good idea, but tearing down old ones seems like not the best investment in resources given such a low probability event.