The Cascadia fault in the Pacific Northwest coast of the US has been extensivly studied.
Ample evidence in the geological record that it has produced large quakes and tsunamis.
So it is likely that it will do so again.
As to when and how big, we don't know enough about tectonics to know.
Too many variables.
Don't remember the exact date, but it produced a substantial quake in the 1700's.
The area had a low population density then, so little effect on human infrastructure.
Now cities and more people mean quakes equivilent to past events are of more consequence.
It is a subduction fault.
These are the type that can produce megathrust quakes and tsunamis.
Whatever works, use it.
A good idea stands on its own value independent of authorship.
If it stands or falls on the credibility of the author, maybe it isn't such a good idea.