@18 - You're basically correct; the hazard to Seattle from a Cascadia Subduction Zone-generated tsunami is small, especially compared to the outer coast. The relatively narrow, shallow entrances to Puget Sound mean not much wave energy will reach us here.
But the Seattle fault that stretches from near the stadiums to southern Bainbridge Island has generated tsunamis as well, and could do so again:
http://www.pmel.noaa.gov/pubs/PDF/wals27… [pdf]
WA DNR has tons of research-based information:
http://www.dnr.wa.gov/ResearchScience/To…