Tsunamis are most likely to appear around tectonic (Tek-ton-ick) plate boundaries, Any type of boundaries from transform, to divergent, to convergent can cause earthquakes. If the earthquake is to happen undersea than the tsunami will occur, The displaced water will be sent in many directions. Coral reefs will be damaged as the tsunami passes over them, but it will slow it down. Tsunami's can also travel at speeds up to 500 mph. And can be up to an hour long.