The fault is roughly 810 miles long and extends to depths of at least 10 miles within the Earth.
The San Andreas Fault is a transform fault which means that the plates are sliding along the fault.
For years the plates will be locked with no movement at all as they push against one another.
Viewed from the ground, however, the features are more subtle.
California suffers thousands of small earthquakes each year but major ones occur only after long intervals.
