How big do tsumamis get? - video
It took a while but it seems everyone has stopped using the incorrect term 'tidal wave' to describe a tsunami. So, now we're all on the same page, hows about we make a further distinction and categorise tsumani into regular tsunami and mega tsunami.
It all sounds very James Cameron but the difference is simple: regular tsunami are created by earthquakes, while their mega brethren are created by landslides displacing water. They're less common but far more destructive, as this descriptive little vid shows.