Southern California’s Five Biggest Earthquakes Ever

Southern California is no stranger to seismic activity, but the recent spate of over 200 earthquakes has everyone on edge. The latest notable tremor was a moderately strong 5.2-magnitude quake that struck Kern County on Tuesday, August 7. This recent activity has raised eyebrows and renewed concerns about seismic stability in the area. To get a better understanding of the current seismic swarm, let’s look at the five largest earthquakes that have shaped California’s seismic history.

Fort Tejon (1857)

On January 9, 1857, the Fort Tejon earthquake, with a massive magnitude of 7.9, struck Southern California at 8:20 a.m. This colossal quake ruptured the San Andreas Fault for 225 miles, shaking with such intensity that it was rated IX – Violent. Adobe buildings at Fort Tejon were severely damaged, injuring several people, while a twenty-mile stretch from Fort Tejon to Elizabeth Lake was left in ruins. 

San Francisco (1906)

A 7.9-magnitude earthquake struck San Francisco in 1906, wreaking unparalleled havoc with a Mercalli intensity of XI (extreme). The city was engulfed in devastating fires that burned for days, destroying over 80% of San Francisco and resulting in more than 3,000 deaths. This disaster stands as the deadliest earthquake in US history, deeply shaping California’s approach to disaster management and urban resilience.

Owens Valley (1872)

Also known as the Lone Pine earthquake, the 1872 Owens Valley quake hit with immense power on March 26. With a magnitude of 7.4, it was comparable in strength to the 1906 San Francisco quake. Nearly all buildings in Lone Pine and surrounding areas were leveled, leaving 27 people dead and 56 injured. With only seven houses remaining out of 59, this powerful tremor remains one of California’s most formidable earthquakes.

Eureka (1980)

This one on the list hit with a magnitude of 7.3 and a Mercalli intensity of VII. It was the largest quake California had seen in 28 years. Though the damage was relatively minor, the partial collapse of a highway overpass on US 101 in Fields Landing resulted in six injuries and significant repair costs exceeding $2 million. The Eureka tremor underscored the seismic risks in the region and the potential impact of even moderate earthquakes.

Kern County (1952)

The Kern County earthquake hit Southern California with a bang, registering a hefty 7.3 on the magnitude scale. The town of Tehachapi took the brunt of the quake, suffering the most damage and loss of life. The initial quake was just the beginning; aftershocks kept rolling in through July and August, including a particularly nasty one on August 22 that clocked in at 5.8. This added another $10 million in damage and claimed two more lives.