Earthquake Facts

Every year, approximately 500 earthquakes occur in the state of California that are large enough to be felt. San Diego County, in comparison to other southern California areas, has sparse seismicity. However, since 1984, earthquake activity in San Diego County has doubled over that of the preceding 50 years. 

Ongoing field and laboratory studies suggest the largest credible earthquake predicted for the coastal and metropolitan areas is a M7.2 on the Rose Canyon Fault and a M7.6 from either the Elsinore Fault or the San Jacinto Fault in the north and east county areas. 

The US Geological Survey has simulated the effects of the next big Californian earthquake and one of their computer models assumes that the next big event on the San Andreas fault will be magnitude M7.8, with a single event in which a rupture starts in Southern California near the Salton Sea and then shoots north along the fault to hit Los Angeles.

In addition, studies suggest the following maximum likely magnitudes for local faults: La Nacion (M6.2 to 6.6), Coronado Bank (M6.0 to 7.7), San Diego Trough (M6.1 to 7.7), San Clemente (M6.6 to 7.7).

It should also be noted that some faults are hidden beneath unperturbed sediments (blind fault) and only discovered after an earthquake occurs.

In the event of an earthquake, the City of Oceanside may utilize its Reverse-911 system (Alert San Diego) and phone calls would be made to residents and businesses with emergency information. Phone calls are made to landlines or to cell phone numbers that are registered with Alert San Diego. Cell phones may be registered free of charge; Click Here to register your cell phone. There is no need to register landlines, for they are automatically in the Alert San Diego system. 

Seven Steps to Earthquake Safety

1. Fix potential hazards
2. Create a Family Disaster Plan and Personal Survival Guide
3. Create a Disaster Supplies Kit
4. Fix your building's potential weaknesses
5. During earthquakes and aftershocks: Drop, Cover, and Hold On
6. After the earthquake, check for injuries and damage7. When safe, continue to follow your disaster plan

Earthquake Preparedness

For more information on how to prepare for an earthquake disaster please download the following information guides: