The typical velocity of a tsunami is around 500 kilometers per hour (310 miles per hour) in the deep ocean.

However, this speed can vary significantly depending on the depth of the ocean:

* Deep ocean: As mentioned above, a tsunami can travel at speeds of 500 km/h or more.

* Shallow water: When a tsunami approaches the shore and enters shallower water, it slows down to speeds of 30-50 km/h (19-31 mph).

It's important to remember that even though the speed decreases, the tsunami's height increases due to the conservation of energy. This is what causes the devastating flooding and destruction associated with these waves.