Why might waves from the same earthquake cause more damage in one area than another?

A tsunami can send a wave in multiple directions. Over time a wave will not have as much energy as did when the wave was first started. So when the tsunami hits land it will not be as strong as another wave generated from that same earthquake. EX: When the tsunami hit Japan it knocked over buildings, meanwhile America was hit with a wave from the same earthquake. However the damage was much less.