Plate Tectonics

Earth's tectonic plates. Plate boundaries are shown in red. Learn more about the geologic features related to Earth's tectonic plates at This Dynamic Planet Modified from USGS

Many forces change the surface of the Earth over time. The largest force that changes our planet’s surface is movement of Earth's outer layer in a process called plate tectonics.

As shown in this picture, the Earth’s outer layer, called the lithosphere, is broken into plates which fit together like a jigsaw puzzle. These plates move very slowly (2 inches per year).

Plates crash into each other at subduction zones.
Plates pull apart at spreading ridges.
Plates slide past each other along large faults.