Earthquakes in California today: live seismic activity across the state

California sits along the boundary between the Pacific and North American tectonic plates, making it the most seismically active state in the contiguous United States. The San Andreas Fault stretches 800 miles from the Salton Sea to Cape Mendocino and is the most famous fault in the world, but it is far from the only one — California has hundreds of active faults including the Hayward, San Jacinto, Garlock, and Elsinore faults.

On average, California experiences two to three magnitude 5+ earthquakes per year and thousands of smaller events. The southern section of the San Andreas has not produced a major rupture since 1857, building stress that seismologists say will eventually release in a magnitude 7.5+ event — the scenario known as "The Big One." Track live California seismic data alongside global activity on our earthquake tracker.

California's earthquake history includes some of the most studied seismic events in history. The 1906 San Francisco earthquake (M7.9) and subsequent fire destroyed most of the city and killed over 3,000 people. The 1994 Northridge earthquake (M6.7) caused $20 billion in damage and killed 57 people in the Los Angeles area. The 1989 Loma Prieta earthquake (M6.9) collapsed a section of the Bay Bridge during the World Series.

The 2019 Ridgecrest sequence (M6.4 and M7.1) in the Mojave Desert was the largest California earthquake in 20 years and caused surface rupture visible from satellite imagery. Each major event has led to updated building codes and improved early warning capabilities.

California operates the ShakeAlert earthquake early warning system, which sends alerts to smartphones via the MyShake app and Wireless Emergency Alerts seconds before shaking arrives. The system detects P-waves at seismic stations and calculates the expected intensity and location of the earthquake before the more damaging S-waves and surface waves reach populated areas.

California's building codes, updated after each major earthquake, require new buildings to meet strict seismic design standards. However, millions of older buildings — particularly unreinforced masonry and soft-story apartment buildings — remain vulnerable. Retrofit programs are underway in Los Angeles and San Francisco, but progress is slow against the scale of the problem. Check the disaster tracker for how California seismicity fits into the broader natural hazard picture.