What controls the speed of a tidal wave?

Answer 1

Think of it this way, water moves because of the underwater current, and the slow moving tectonic plates. Depending on the strength of a storm, the current can be amplified to a tremendous amount and make the movement of water faster. As is the tectonic plates can send an enormous thrust to make tsunamis travel hundreds of miles.

Answer 2

The wave equation (mathematically-speaking).