Interesting, thanks. The odds they give are in in 400 in the next 2 weeks. Is not just BC; would be from northern California (Mendocino) through Washington state. But, the odds must be based on some stress model: I don't think they've seen tremor actually immediately preceed a Great quake....yet. Also, I don't know the latest research, but I doubt the whole subduction zone goes in one M9 everytime. It may have in 1700, but other times it may go over a longer period of time in a series of M8+ quakes, which would normally have smaller tsunami, and which might not too much affect buildings at the opposite end of the subduction zone.

qualification on these comments: I do not read the seismology journals on this sort of stuff: I encounter some of it at talks/posters/meetings.

Chris