March 29, 2014 Earthquake: La Habra, Brea, Fullerton, California, United States

At least 20 buildings damaged, seiches, power outages, gas leaks and water mains damaged in the Brea-Fullerton area. A landslide occurred in Carbon Canyon. Felt (VI) at Brea, Buena Park, Fullerton, La Habra, La Mirada, La Puente, Midway City, Placentia, Rowland Heights, Walnut, West Covina and Whittier. Felt in much of Los Angeles, Orange, Riverside, western San Bernardino, San Diego and Ventura Counties and in parts of Imperial, Inyo, Kern, San Luis Obispo and Santa Barbara Counties. Also felt at Las Vegas, Nevada and in the Ensenada-Tijuana area, Baja California.

Tectonic Summary

A M5.1 earthquake occurred at 9:09pm on March 28, 2014, located 1 km (1 mile) east of La Habra, CA, 5 km (3 miles) north of Fullerton, CA and 33 km (21 miles) ESE of Los Angeles. The depth of the event is 7.5 km.

The event was felt widely throughout Orange, Los Angeles, Ventura, Riverside, and San Bernardino counties. It was preceded by two foreshocks, a M3.6 at 8:03pm and a M2.1 at 8:16 pm. There have been 38 aftershocks as of 10:45pm, the largest of which was a M3.6 at 9:30pm, and was felt locally near the epicenter. The aftershock sequence may continue for several days to weeks, but will likely decay in frequency and magnitude as time goes by. The maximum observed instrumental intensity was VII, recorded in the La Habra and Brea areas, although the ShakeMap shows a wide area of maximum intensity of VI. The maximum reported intensity for the Community Internet Intensity Map (Did You Feel It?) was reported at VI in the epicentral area.

This sequence could be associated with the Puente Hills thrust (PHT). The PHT is a blind thrust fault that extends from this region to the north and west towards the City of Los Angeles. It caused the M5.9 1987 Oct. 1 Whittier Narrows earthquake. Previously, the M5.4 2008 Chino Hills earthquake occurred in this region. It caused somewhat stronger shaking in Orange County and across the Los Angeles Basin. The moment tensor shows oblique faulting, with a north dipping plane that approximately aligns with the Puente Hills thrust.

The demonstration earthquake early warning system provided 4 second warning in Pasadena.

(above from reference #1053)

The Orange County Register reported the quake caused $2 million in damage in La Habra, Brea and Fullerton.

In Fullerton, 13 water mains broke and about 70 residents were displaced from their homes when they were declared temporarily uninhabitable. "Immediately after the earthquake, we activated our Emergency Operations Center which led to our quick responses to repair water leaks and ensure the safety of buildings in our city," said Fullerton Mayor Doug Chaffee in a statement released last week. "Thankfully, there were no injuries reported as a result of the earthquake." (reference #10884)

Orange County sustained about $10.8 million in public property damage after a 5.1 earthquake shook the region on March 28, according to the latest estimates.

On Tuesday, the O.C. Board of Supervisors officially declared the earthquake a local emergency, and asked Governor Jerry Brown to declare a state of emergency in the county. That declaration could open the door for federal aid, if federal damage surveyors agree with the estimate.

The initial damage estimates for the quake were considerably smaller. Last week, the three cities closest to the epicenter - La Habra, Fullerton, and Brea - totaled their damage to public and private property at about $2.6 million. Much of the bump came from issues on the campus of California State University-Fullerton, which reported $6.5 million in damage. The school's initial tally was about $500,000. (reference #10899)

In Brea, several people suffered minor injuries during a rock slide that overturned their car. (reference #10905)