Chapter 1:

The Basics

First of all, it turns out, that the Earth is not solid. I mean, it’s as solid as it needs to be. We’re not going to fall through it or anything, but it is not actually solid all the way through. Even the Earth’s crust, the actual land we walk on, is not one solid piece.

This means the correct answer to “Does the ground move?” is: “Yes.” (You may remember that my answer was “Only when a bus goes by.”) In fact, pieces of the Earth are always moving. They move toward each other and they move away from each other. When they collide or rub up against each other — even at very slow speeds — they can cause earthquakes, create or destroy mountains, cause volcanoes to erupt, and overall make dramatic changes to the Earth, very quickly.

The good news is that all this moving and changing of the Earth’s surface is what makes the Earth such a great place for animals, people, and plants to live. The destruction caused by earthquakes, volcanoes and tsunamis actually renews the land and makes the soil fertile.