Kate, I did not mean that this Sumatra quake would make significant seiches near Seattle...I meant it would be worth someone looking into what would happen if there was a nearby great quake. I think the Seattle fault is a steep fault that comes to or close to the surface. It would probably not be capable of a great (M8+) quake, but it is possible that it could break at the same time as the underlying subduction zone. I do not know whether the paleoseismologic research has shown this to be the case ever, or when the last quake on the Seattle fault was (although I have an article on this buried somewhere here). A quake just on the Seattle fault would not cause a large tsunami, unless it triggered a large submarine landslide. It is highly unlikely that an earthquake that only ruptured the Seattle fault would cause a large tsunami that could cross the Pacific. These are my opinions...I don't study those faults.
Chris