Earthquakes in San Francisco
San Francisco is built on one of the world's most seismically complex urban landscapes, crisscrossed by the San Andreas, Hayward, Calaveras, and numerous other active faults. The 1906 earthquake destroyed the city; the 1989 Loma Prieta earthquake killed 63 people. A major earthquake on the Hayward Fault beneath the East Bay is considered by many seismologists to be the most likely near-term catastrophic earthquake in California.
Why Does San Francisco Face Earthquake Risk?
The San Andreas Fault passes 30 km west of downtown San Francisco, while the Hayward Fault cuts directly through the densely populated East Bay. Berkeley, Oakland, and Fremont all sit directly atop the Hayward Fault. Scientists give a 33% probability of an M6.7+ Hayward Fault earthquake within 30 years.
Active Fault Systems
- San Andreas Fault
- Hayward Fault
- Calaveras Fault
- Rogers Creek Fault
Safety Advice
San Francisco's Earthquake Early Warning system (ShakeAlert) provides seconds of advance notice via Wireless Emergency Alerts. Know your neighborhood's liquefaction and landslide hazard zone from USGS maps. Older unreinforced masonry buildings (URM) and "soft story" apartment buildings carry higher collapse risk.
Historical Earthquake Context
The April 18, 1906 earthquake (M7.9) leveled San Francisco, triggering fires that burned for three days and killed an estimated 3,000 people. The October 17, 1989 Loma Prieta earthquake (M6.9) collapsed a section of the Bay Bridge and the Cypress Freeway, killing 63 people.
Significant Earthquakes Near San Francisco
| Year | Magnitude | Event | Deaths |
|---|---|---|---|
| 1989 | M6.9 | California, USA | 63 |
Fault Maps & Tectonic Setting
Tectonic and seismic hazard maps from Wikimedia Commons, USGS, and NASA — open licenses (CC / Public Domain)
Maps sourced from Wikimedia Commons, USGS, and NASA under open licenses. Attribution required where specified. Click any map to enlarge.
FAQ
Frequently Asked Questions
What is the Hayward Fault threat to San Francisco?
The Hayward Fault, which runs through Berkeley, Oakland, and other East Bay cities, has a 33% probability of generating an M6.7+ earthquake within 30 years. This event would likely cause greater destruction in the Bay Area than the 1989 Loma Prieta earthquake due to the Hayward Fault's direct path through densely populated urban areas.
Which buildings in San Francisco are most at risk?
Unreinforced masonry (URM) buildings, soft-story wood-frame apartments, and buildings on liquefaction-prone fill in areas like the Marina District and South of Market are among the most vulnerable. San Francisco has a mandatory seismic retrofit program for the highest-risk building types.
How seismically active is San Francisco?
The San Francisco Bay Area experiences roughly 1,000 earthquakes per year. The Hayward Fault runs through the East Bay and is considered overdue for a major rupture — USGS estimates a 33% probability of a M6.7+ Hayward Fault event within 30 years. The San Andreas Fault also passes within kilometers of the city.
What should I do during an earthquake in San Francisco?
Drop, Cover, and Hold On under a sturdy table or against an interior wall. Do not run outside during shaking. After shaking stops, expect aftershocks, check for gas leaks, and exit using stairs. Enable ShakeAlert on your phone for advance earthquake warnings that cover the Bay Area.
Where can I see live earthquake data for San Francisco?
Track earthquakes near San Francisco on the Earthquake Globe app or at earthquakes.site/map?country=california. USGS provides real-time Bay Area seismic data at earthquake.usgs.gov. The Berkeley Seismological Laboratory also publishes Bay Area earthquake data at seismo.berkeley.edu.
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Get Earthquake Alerts for San Francisco
Earthquake Globe sends real-time push notifications filtered by magnitude and location. Free on the App Store.
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