Putting on my "general geohazards communicator" hat here for a moment: In all but the *very* most extreme earthquake-generated tsunami events, locations more than ~100ft above sea level are generally safe. In vast majority of such events, "vertical evacuation" is the way to go!

That said, there have been a handful of recorded contemporary quake-generated tsunami events--arising from megathrust subduction zone events--where maximum tsunami height has been in 100-150 foot range (including devastating 2011 Tōhoku event east of Japan @ ~133ft max height).

Some estimates suggest that, in a plausible worst case scenario, a ~M9 quake within Cascadia Subduction Zone off Pacific NW coast could conceivably generate tsunami inundation up to ~100ft above local sea level--though "lesser" inundations in the dozens of feet are more likely.

Much larger "megatsunamis" have occurred in Earth's history, though these have generally caused by events other than earthquakes involving extremely large & sudden displacements of water--like massive undersea landslides or "extraterrestrial impactors" (comets or meteorites).

But for majority of tsunami events, it's usually enough to get 20-30 feet above sea level; even in largest quake-generated events, 100-150 feet is a good bet. If there's ever a major comet or meteorite impact, well...I suppose that's a different story. Tough then we might have bigger problems...