answer:Here‘s an article about the aftermath of the tsunami in Sumatra. Apparently toads are among the animals that can predict earthquakes! I would think that there would be some pretty strongly-felt effects underwater as well as on land. It’s tough to find information online about it – maybe there haven’t been a whole lot of studies, maybe I’m just not much of a Googler. But it would make sense for coral reefs to be affected greatly depending on the magnitude, which in turn would change the underwater ecosystem at least somewhat.