A tsunami is defined as a long and high sea wave that is usually caused by a disturbance like an earthquake. A tsunami can affect the earth in a number of ways. When it comes onto the shore it can crash over the land and destroy the landscape of the land. A tsunami puts a lot of salt water on the land which can erode it. The salt can kill the organisms, ruin plants and vegetation for the future, and destroy things that are built on the land.