You lost me on the math! But one thing - the tsunami (either due to submarine EQ or landslide) doesn’t show much if anything on the water surface mid-ocean. But it is the shallowing of the water at the shelf that concentrates the energy. Is your math more for waves at the surface?
EQ’s have only been shown to show maximum waves of about 30 meters iirc - due to the “limited” amount of uplift in any one event (on the order of tens of meters). Whereas a landslide can fall from hundreds of meters. Of course the landslide is a pinpoint as you say, and a fault can run for miles.
The following paper gives a rebutal against the huge landslide tsunami. The probablity is that a landslide would occur over a period of time, rather than one huge single block of rock.
http://blogs.agu.org/landslideblog/2013/12/13/canary-islands-tsunami/
I have read of the Alaskan wave - a man and his son rode it out in a boat. Got swept over a pennisula that was hundred+ feet tall iirc!! Quite the ride. And yes - it was a fairly tight fjiord. I think they also said the natives had stories of this happening in this fjiord - and so their camps were around a bend near the ocean.
I think that's correct, since a wavelength much less than the depth is what defines this term ( i.e. surface wave.) Tsunamis originate from broad upheavals of the ocean floor, and have a long wavelength and high speed of propagation.
A landslide can produce a high amplitude, but not a long wavelength, as far as I understand it.
That was it.