How does the shape of the beach affect the amplitude of the waves of a tsunami?
The wave generated by a tsunami is really a large swell. Swells continue along until they meet the resistance of shallowing water. When the depth of the water can no longer handle the volume of water, the wave will rise up on top of the sand in shallower water and break. If the land form creates a gentle slope then the tsunami will appear as a very strong tidal flow. If the shore is steep then the swell will rise up and break against the beach. Most damage is not done by a large crashing wave, but by the sheer volume of water that is flowing onto the land and carrying debris along with it.
