What controls the speed of a tsunami wave?

Try this Earthlearningidea to find out what does control the speed of a tsunami wave In this activity, pupils look at the relationship between the depth of the water in the tank and the velocity of a water wave generated by lifting and then dropping one end of the tank.
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Try counting the number of waves which hit the end of the tank in both water depths shown in this video clip. Which is faster - shallow or deep water?
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