Landslip / glacierslip 'tsunamis' in confined waters are not really the same as those from subsea earthquakes. The landslips just slop the water along the fjord or bay. The volume of water is tiny compared to big 9.0 oceanic quakes, like those for the Indian Ocean (2004) or Japanese (2011) tsunamis. We really need a different word for the local landslip type.

Here is a famous landslip-tsunami event with one eyewitness account:

https://en.wikipedia.org/wiki/1958_Lituya_Bay_earthquake_and...

See the book Wildest Alaska: Journeys of Great Peril in Lituya Bay by Philip Fradkin.

P.S. Yes, an earthquake triggered the landslip, but the earthquake did not displace the water.