An earthquake is a sudden, rapid shaking of the earth caused by the release of energy stored in rocks. Earthquakes are detected every day in California by sensitive instruments called seismographs. Very few of these earthquakes are big enough to be felt by people, and even fewer are big enough to cause damage. Alaska has the most.
Faults are breaks in the earth's crust where one side has shifted.
California's most-famous fault is the San Andreas, which is hundreds of miles long and runs almost the entire length of the state. Different countries have different earthquake legends. The turtle is balanced in turn by a cobra. When one of these animals moves, the earth trembles and shakes. A tsunami is a series of large waves, as much as 50 feet high, that can move faster than a person can run.