There is a subduction zone right off the Oregon/Washington coastlines that every few centuries lets rip with earthquakes. These type of earthquakes tend to be very powerful, around seismic level 8 or 9, with the shorelines dropping about 15 to 20 feet, and the tsunamis expected up to 100 feet high.
Frankly I think they’re exagerating on the estimated heights of the tsunamis, but I’m not an expert.
There was a certain cove in Alaska that had a tsunami wave travel up it during the 1964 quake, google it and tell everyone how far the water was pushed in height.
Three guesses, it was more than 10 feet, more than 50 feet, more than 100 feet.
“There is a subduction zone right off the Oregon/Washington coastlines”
The Pacific Northwest is the only region on the Pacific ring of fire not to have had an major earthquake in the last 50 years. Its only a matter of time. The Juan de Fuca plate last had a major quake in 1700, also a 9.1