I’ve no background in this sort of thing but don’t you need a certain time of topography for the water to encounter as it reaches the shore? It has to draw water from the land and build itself on top of the water that is drawn out? Also, I think, it’s impossible for water to climb that high. It just doesn’t seem possible to have a wall of water that high in the middle of the ocean.
Yes. The famous Maverick's surf spot off of Half Moon Bay, Ca gets its enormous waves from a deep offshore trench. When the waves make landfall, all that big water has to go somewhere -- and that somewhere is UP.
The wave will start sounding when the depth equals half of the wavelength. For tsunamis, that wavelength is pretty long, and the wave might only be a meter or two at most in the deeper ocean. In the shallows, it is a question of how high the water can pile up. No one really knows what, if any, maximum height there is, but heights in excess of 100 ft. have been recorded.