Seattle is protected toward the southern end of the enclosed Puget Sound.
Coastal areas, not so much, but then this potential volcano is over three miles down.
Years ago a scientist predicted that should an earthquake cause a tidal wave in Puget Sound, the wave would move so fast that it would pass by Seattle and then pass by Tacoma to crash up into Olympia where Puget Sound ends.
It is really flat in that part of Olympia so likely the wave could travel a fair distance. Maybe get as far as the Capitol Builiding!