Personally I think it will dissipate in the ocean to negligible hight before reaching land, like the wiki article suggests
You make a good point, on the dissipation, However if you, look at the pictures of Lituya Bay (wiki reference), you can understand why the force and the height was what it was, there is no lateral movement for the water, and when it did reach the mouth of the bay, one can see why it simply dissipated.
http://www.alaskacruise.com/Places/LituyaBay.html
Lituya Bay Tsunami:
http://www.extremescience.com/BiggestWave.htm
This was an above sea event, (mountain collapsing into water), same as Krakatoa, which caused substantial damage, but the resulting Tsunamis (damage wise) was localised, the effects, were recorded further afield as swells.
http://vulcan.wr.usgs.gov/Volcanoes/Indonesia/description_krakatau_1883_eruption.html
http://en.wikipedia.org/wiki/Krakatoa
http://www.drgeorgepc.com/Tsunami1883Krakatoa.html
The last article above, had an interesting bit in it:
The speed of the waves was limited by the relatively shallow depth of the sea in the area.
Which led me to find this article, about Tsunami speeds and depth of water:
Physics of the tsunami :
Hence in very deep water, a tsunami will travel at high speeds and travel great distances with limited energy loss. For example, when the ocean is more than 5000 metres deep, unnoticed tsunami travel about 890 km per hour, the speed of a jet airplane.
And in another article (very nice PDF) of Cumbre Vieja:
(worst case) a 500km cube block 25 km long 15km wide and 1400m thick slides into the ocean and down the steep offshore slope for about 60km to a depth of 4000m
http://www.es.ucsc.edu/~ward/papers/La_Palma_grl.pdf
That would displace millions of litres of deep water, making it more of an undersea event, therefore making it possible to reach the distances mentioned.
The Tsunami we witnessed a few years back was also an undersea event, (minor one), yet the damage it did was enormous and the death toll horrific.
So i agree with the idea of dissipation when it is a shallow and above sea event, but would have to disagree with the undersea event scenario.
