Moving PlatesThe surface of the Earth moves all the time. This may not be obvious. Usually the plates of the Earth slide past each other at a rate of two centimeters per year. But sometimes they get stuck. Then we have an earthquake. During an earthquake it is obvious that the Earth can move. Earthquakes move sections of a plate several feet at once.
The picture to the left shows an example of a typical scar left in the crust from the motion of the earth. Such a scar, along which plates slide against each other is called a fault .