Some Facts about Earthquakes

1. In 1769, the earliest reported earthquake was felt by Spanish explorers. It took place about 30 miles southeast of Los Angeles.

2. The magnitude of an earthquake is the measure of how big an earthquake is. It does not vary with location. However, the intensity of an earthquake is how much shaking is generated by an earthquake. The intensity does vary with location.

3. Every year, southern California has an average of about 10,000 earthquakes. The majority of these quakes are minor and go unnoticed by the general public. Only a few hundred of these quakes are above an M3.0, and about 15-20 are greater than M4.0. If a large earthquake takes place, the aftershocks will continue for many months.

5. The typical depth of an earthquake is about 50 miles below the earth's surface.

5. European settlers first experienced an earthquake in America in 1663.