This was "only" an earthquake caused tsunami, which for some reason unknown to me has an inherent top limit of 30 feet or so on the shore height of the wave(s) it will produce.
Tsunamis caused by very large landslides or impacting asteroids(mega-tsunamis) have the potential to produce waves that will reach heights of one thousand feet or more when reaching land. There is a volcano on Las Palmas in the Canaries Islands called the Cubres Viejos which has the potential to collapse and produce a 1,000 foot wave hitting the entire eastern seaboard of North America and the Caribbean 6 to 8 hours later - meaning goodbye New York City, Boston, Norfolk, Miami, Jacksonville, Charleston, very possibly Philadelphia, Washington, Baltimore and all other places and people below one thousand feet of elevation and not sheltered behind higher ground or long stretches of land. Archeologists working in Washington State have found evidence of past megatsunamis, possibly caused by big chunks of the Hawaiian Islands falling into the sea. Just a cheery thought for this holiday season.