What Are Tectonic Plates?
1. Different Layers
From our viewpoint on Earths surface, it seems as though Earth is a single solid rock, but that is not entirely true. It is actually made up of a number of layers and each layer has different characteristics. The outer layer, the layer that we walk and live on every day, is known as the crust. Earths crust is very thin, relatively speaking. It is as thin as 3 miles deep in some places, whereas it can be as much as 15 miles deep in others. The crust is thinner beneath the oceans (oceanic crusts) and thicker when on dry land (continental crusts).
