California

Near California the Pacific Plate is moving north relative to the North American Plate.

Implications of this model:

• It's not so easy to move rock on rock!
• It sticks for a long time, then the fault breaks and one side moves relative to the other all at once.
• Result: an earthquake.

Here is a more detailed view, near San Francisco. There are several faults. The main one is the San Andreas Fault.

ASTR 121 Home