If you live in California, sooner or later you will feel an earthquake, and depending on what part of the state you are in, earthquakes could be a regular thing.

California registers hundreds of earthquakes per year, but the majority of these are of low magnitudes and may not even be felt by anybody. Only the state of Alaska has more -and larger- earthquakes.

The Golden State generally gets two or three large earthquakes every year that are strong enough to cause moderate damage, according to the California Department of Conservation.

Earthquakes are considered “moderate” if they are between magnitude 5.0 – 5.9, “large” if they are between 6.0 – 6.9, “major” means between 7.0 – 7.9, and “great” if they are above 8.0, according to the DOC. 

The so-called “Big One” that is talked about in California is a hypothetical magnitude 7.8 or stronger earthquake that would likely happen in Southern California and cause upwards of 1,800 deaths and more than $200 billion in damages, according to the U.S. Geological Survey.

How many faults are in California? 

Faults are fractures in the crust of the Earth where one side can move relative to the other side, and these can be as long as several hundred miles.

There are more than 500 active faults and 15,700 known faults in the state, according to the California Earthquake Authority, an independent organization created by the state to manage earthquake-related insurance policies. 

Most Californians live within 30 miles of an active fault, the CEA said. 

The faults are located across two plates in California, which are the Pacific Plate and the North American Plate.

The primary boundary between those two plates is the San Andreas Fault, which runs north to south along the Northern California coast and then moves inland in the southern part of the state and on to Baja California.

What is the San Andreas Fault? 

The “Big One” would happen along the San Andreas fault, and it would be so destructive because of the large population that lives along it.

The San Andreas Fault runs for more than 800 miles in California, where it goes from the interior of the state in the south, somewhat parallel to the coast until it reaches the Pacific just south of San Francisco.

From this point north, it meanders along the coast before heading west just south of Eureka.

Many Californians live and work on the west side of the fault, in the Los Angeles area, the central coast and part of the Bay Area.  

To see where if you live here a fault line, click or tap here

What causes earthquakes? 

According to the U.S. Geological Survey, an earthquake is caused by movement on a fault. The tectonic plates are always slowly moving, but they get stuck at their edges due to friction, the USGS said. 

“When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earth’s crust and cause the shaking that we feel,” the USGS website reads.