The very biggest require proximity and geography. But you can get to many times larger than normal ones just by proximity to the thing that is causing the tsun

The very biggest require proximity and geography. But you can get to many times larger than normal ones just by proximity to the thing that is causing the tsunami. See https://www.youtube.com/watch?v=k-DJkj5yr9E https://www.youtube.com/watch?v=k-DJkj5yr9E for a computer simulation of the Etna megatsunami that hit the Mediterranean 8,000 years ago. See https://www.youtube.com/watch?v=PQcpys0QHmA https://www.youtube.com/watch?v=PQcpys0QHmA for a different simulation that focuses on just the hardest hit areas. (The two simulations are of different models of the event with very different wave sizes. I have no idea which one is closer to what happened.)