I've drawn up a set of landmasses for my story, and now there's a tsunami headed for them. I know where the tsunami is coming from, and I could decide how big it is, or any other characteristics of it.

*What parts of the coastline will be devastated and what parts will escape unscathed?*

For example, if the landmasses look like this:

[![caribbean map](https://i.stack.imgur.com/Do50u.gif)](https://i.stack.imgur.com/Do50u.gif)

and a tsunami emanates from Puerto Lempira (Honduras), does Jamaica protect Guantanamo? Is Maracaibo protected by that thumb of Colombia sticking out into the sea? Is Havana safe because it's on the far side of Cuba?

How can I figure this out for my *own* fictional setting?