July 21, 1952 Earthquake: Kern County, California, United States

Reference #45:

13 killed and many injured. $20 million property damage by main shock and total of 60 million for series of shocks. Severe structural damage in Tehachapi and Arvin. Many tunnels severely damaged. Agricultural section of Kern County suffered heavy crop losses due to irrigation system failures. Mag 7.7

Reference #3684:

The earthquake with the greatest magnitude (7.7) occurred on July 21, 1952. There were six additional earthquakes of magnitude 5 or greater on July 21. he epicenters were in the vicinity of a triangle formed by Bakersfield, Tehachapi, and Wheeler Ridge. The July 21 shock was the highest magnitude earthquake in California since 1906 (San Francisco). Thirty-seven schools were sampled, representing about three-fourths of the school damage in the area. The 1952 value of the schools sampled was about $14 million. There were 14 deaths in Kern County communities resulting from these earthquakes.

Reference #1128:

This was the main shock of the Kern County series and the largest earthquake in the United States since 1906. Damage to property was estimated at $50 million.

Twelve persons were killed, nine of these at Tehachapi in the collapse of a brick wall. Eighteen persons were hospitalized and several hundred were given first-aid treatment.

At Arvin, Bakersfield, and Tehachapi, old and poorly built masonry and adobe buildings were cracked; many collapsed.

Reference #542:

This earthquake was the largest in the conterminous United States since the San Francisco shock of 1906. It claimed 12 lives and caused property damage estimated at $60 million.

Reference #11909:

The 1952 Kern County earthquake is the second-largest earthquake in California in the twentieth century; it was preceded by other events in the region, including a Mw 4.6 earthquake on 23 Feb. 1939.

The precise magnitude, epicenter, and hypocentral depth, however, remain uncertain due to data limitations. Ben-Menahem (1978) estimated Mw 7.3 based on analysis of teleseismic surface waves. Gutenberg (1955b) estimated ML7.7. The current US Geological Survey catalog estimate is Mw7.5. Our preferred epicenter is 34.977N, 119.033W (Gutenberg 1955a; Ishida and Kanamori 1980; Felzer 2013; Hutton et al. 2010; Hutton, pers. comm. 2016; see electronic supplement for details).

Although we cannot rule out the possibility that the 1952 earthquake was purely tectonic in origin, the proximity of the rupture zone for this event to the producing reservoir and the short time lapse between onset of deep production and the occurrence of the 1952 earthquake (98 days) supports the hypothesis that this event was triggered by stress changes associated with oil production.