Major International Tectonic Plates

Plates in General:

The earth is divided into sections, better known as plates. There are seven main plates and many small plates that make up the earth. Each plate is about 50 miles thick and they move a few inches annually. The direction of the plate's movement is determined by its size and the interaction of the surrounding plates.

Plate Boundaries:

There are three types of plate movements found on each of their boundaries. Convergent, divergent, and transform-fault are the three types of boundaries. These types of boundaries produce sometimes deadly earthquakes and volcanoes.

On a Convergent boundary the plates move toward each other and collide to form such land formations as mountains and volcanoes. On divergent boundaries plates move away from other plates. This creates sea-floor spreading, or the production of new material to the ends of the plates. On a transform-fault boundary plates move horizontally past another plate. An example is the San Andreas fault in California.

(All images on this page provided by United States Geological Survey)