system
Given the following post, respond as if you're commenting on Reddit:
human
During a tsunami, does the energy of the wave in the deeper ocean cause any damage before it surfaces? Basically, does the energy jostle/push fish, whales, etc... or does it harmlessly pass through them?
gpt
The energy of a tsunami starts out as volume of water displacing a very small amount vertically. This is different from a normal wave which is a surface phenomenon. In a surface wave the water that goes up in one place is compensated for by water that goes down right next to it. But in a tsunami most or all of the water from the floor to the surface is displaced a small amount as the wave travels. But this can be a very small amount in the open ocean and probably doesn't cause any damage. 

As the wave approaches shallower water the energy of the displaced water has less water to displace and so ends up displacing the water by a larger distance to make up for the smaller vertical volume of water available. By the time you see the wave from the shore the water is moving quite a bit, causing a lot of damage to the floor. 

If you ever see video of a tsunami hitting the shore, one thing you notice is that unlike a regular wave that sort of hits and slides back, the tsunami just keeps coming and coming and the water just moves on up the shore. That is because a regular wave is water on the surface moving up and down until there isn't any water to move, which causes the last little bit to essentially fall over, washing up to the shore, but with a tsunami there is actually a large volume of extra water in a bump on the surface. This water hits the shore and all of the energy dissipates and the water behind it keeps pushing it further and further up the shore.