The M_w 7.3 1952 Kern County earthquake was one of California’s biggest earthquakes to date. Seventy years after the main event on July 21st, 1952, it has been forgotten by many, but still remains a significant event in the history of seismology.

The earthquake occurred on the White Wolf fault near Bakersfield, California, close to the intersection of the San Andreas fault and the Garlock fault. The epicenter of the quake was near Lebec, but the greatest impacts were felt in the city of Tehachapi, where the earthquake was responsible for more than 30 casualties in a town with less than 2000 residents.

The effects of the quake were felt all over California and Nevada, from San Francisco to Los Angeles to Reno. Power outages occurred in Los Angeles and high-rises shook in San Francisco. In the Owens Valley, it disturbed salt beds and broke a pipeline.

It was the largest earthquake in the state since the 1906 San Francisco earthquake and the first major earthquake in Southern California after the 1857 Fort Tejon earthquake.

In Tehachapi, the earthquake caused at least $50 million in property damage, which amounts to $559 million in today’s dollars. More than a hundred buildings had to be torn down as a result. 

Main Street, Tehachapi, after the earthquake of July 21, 1952. (Credit: World Wide Photo)

Before the 1952 mainshock, the White Wolf fault (a reverse fault with a left lateral component) was believed to be a small fault that could not produce a big earthquake. And therefore, the 1952 Kern County earthquake came as a shock to a community completely unprepared for the event.

After the event, seismologists found that the displacement seen on the surface was smaller than expected from an event of such magnitude, which meant that most of the movement on the fault happened beneath the surface and the slip was much deeper.

Vertical fracture on the northeast side of Bear Mountain, along the White Wolf fault. (Credit: University of California, Seismological Station)

While the earthquake itself caused a lot of damage, its aftershocks caused additional harm and destruction. Within two months of the mainshock, Caltech had recorded 188 aftershocks of magnitude 4 or higher. 

The most significant of the aftershocks was the M_w 5.8 1952 Bakersfield earthquake, which occurred just a month after the main event on August 22, 1952. In this instance, the damage was confined to downtown Bakersfield. 

Two people died, 35 were injured, and $10 million worth of damages occured ($111.8 million in today’s dollars). The Bakersfield aftershock was not the biggest aftershock in the Kern County sequence (there was a Mw 6.3 earthquake on July 29), but it was the most impactful due to its location.

The 18 aftershocks that occurred between the main event and the 1952 Bakersfield earthquake had already weakened the existing structures in Bakersfield. Additionally, the seismic waves generated in this aftershock had a higher frequency, which specifically targeted smaller buildings.

The 1952 Kern County earthquake and its aftershocks showed the importance of having better building codes and making buildings stronger and safer.

At the time of the 65th anniversary of the 1952 Kern County earthquake, Glenn Pomeroy of the California Earthquake Authority said, “History shows that damaging earthquakes can happen across California at any time. This anniversary serves as a reminder that it’s wise to take steps to be prepared for quakes, which come with no warning.”

Additional Reading:

1952 Kern County Earthquake Information: SCEDC
Memories of the 1952 Kern County Earthquake
Mighty '52 earthquake took toll in Tehachapi
C-SPAN Cities Tour: 1952 Bakersfield Earthquake
 

About the Author

Shreya Agrawal is an earth scientist and a journalist focusing on climate change, environmental and social issues and politics. She graduates from USC in 2023 with a dual bachelor's degree in Geological Sciences and English, and a masters degree in journalism. She hopes to better communicate science to the public and bridge gaps in science communication.