A magnitude 5.1 earthquake, which struck La Habra, caused minor damage to buildings, gas and water main breaks and some street flooding in northern Orange County, but no injuries were reported.
The temblor hit at 9:09 p.m. Friday at a depth of five miles, one mile east of La Habra, and was preceded by a magnitude 3.6 quake in the area at 8:03 p.m., according to the U.S. Geological Survey.
The earthquake was felt from the Mexico border to the Central Valley in at least seven Southern California counties, including Los Angeles, Orange, Riverside, San Bernardino, San Diego, Ventura and Kern.
The temblor was followed by about 40 aftershocks, two greater than magnitude 3.0, USGS seismologist Robert Graves said. There were no reports of surface rupture, Graves said.
The shaker was estimated to be about 10 times larger than the March 17 magnitude 4.4 quake near Encino in terms of energy released, says Lucy Jones, a visiting research associate at Caltech's Seismological Laboratory.
The March temblor struck early on a Monday morning. This one, 12 days later, was a reminder to the community, to be prepared Mayor Eric Garcetti said.
"L.A. residents can visit readyla.org for guidance on how to best prepare for the next earthquake, including potential aftershocks," Garcetti said.
L.A County Public Works Department announced this morning that dam operators reported no signs of damage at 14 major dams inside Los Angeles County.
However, the city of Fullerton and nearby communities in northern Orange County did suffer damage to buildings, with 50 residents displaced, according to city officials.
In La Habra, police received multiple reports of broken windows and gas was shut off in the 1200 block of South Beach as a precautionary measure, according to police spokeswoman Cindy Knapp.
Police and city building officials in La Habra were also investigated possible structural damage to apartment complexes in the 2500 block of West Whittier Boulevard, the 400 block of North Idaho Street and 700 block of West First Avenue, Knapp continued. Residents were evacuated from these locations but, so far, no buildings have been red-tagged.
The Red Cross opened a shelter at the La Habra Community Center at 101 W. La Habra Blvd., she said. According to Knapp, about 50 residents came to the center but many have since left.
Knapp also told NBC4 that the city has had three water main breaks, but said no injuries were reported. NBC4 also reported six water main breaks in the city of Fullerton.
In Brea, the quake caused a rock slide which overturned a car and blocked Carbon Canyon Road, according to authorities.
Southern California Edison reported that 1,748 customers in the La Mirada area lost power. Edison spokeswoman Susan Cox said the outage, which occurred at 9:11 p.m., was most likely related to the earthquake.
The Los Angeles County Fire Department received reports of gas leaks in the Rowland Heights area and scattered minor damage, said department supervisor Ed Pickett.
The Los Angeles police and fire departments conducted an assessment and reported no damage in the city, Garcetti said.
Disneyland shut down rides as a precaution, NBC4 reported.
Train services were also affected, with Metrolink announcing that its service from San Bernardino to Union Station was running 150 minutes behind schedule, and its Orange County line 644 to Oceanside 42 minutes late. Those delays were a result of precautionary slowing due to the earthquake, Metrolink said on its website. However, No damage to the Metro Rail system was found following a check of all lines, the agency's Paul Gonzales told City News Service.
USGS's Graves said about 40 aftershocks had followed the initial temblor.
Jones said the most likely time for a follow-up earthquake was over the course of the night.
"Tonight is the most likely time (for an earthquake) and the next hour is the most likely time," Jones said. "Each hour we pass without an earthquake reduces the chances."
The fault that caused the earthquake was close to, but separate from the Puente Hills thrust (fault) that was responsible for the 1987 Whittier Narrows earthquake, says Caltech's Jones.
"There is no definitive information on the fault," Jones said. "There are several active faults in that region that have been mapped."
Jones said her preliminary research said the last recorded activity of this particular fault was recorded on July 8, 1929.
Minor damage was expected from earthquakes the size of tonight's magnitude-5.1, which struck about five miles to the northwest of the magnitude- 5.4 Chino Hills earthquake of 2008, Graves said.
A lieutenant at the Orange County sheriff's office in Silverado Canyon said the shaking lasted nearly 30 seconds.
The earthquake set off car alarms in Anaheim Hills, a resident said.
A lieutenant at the San Diego County Sheriff's Department said residents reported feeling the earthquake in the North County and as far south as Mission Valley.
Hannah Hirzel, 17, said she was home in her room in Placentia, four miles from the epicenter, when she felt a jolt. It was the second earthquake she felt that night, but this one was different. "It was longer and more intense," she said.
"I was home alone and I ran out of the house," Hirzel told CNS. "I was sitting where my bookshelf fell, but I ran really quick."
Her bookshelf and other furniture toppled over onto where she had been moments before. Food also fell out of the pantry, with items breaking on the kitchen floor, and there are cracks in the walls, she said.
Hirzel said she was not hurt, but plans to change the design of her room to make it safer, especially by making the bookshelf more secure.
"My mom says we are going to hook it to the wall and I think I'm going to sleep downstairs tonight," Hirzel said
Jones described the past 20 years since the January 1994 Northridge earthquake as some of the quietest for earthquakes in recent California history.
"We might be getting back to the more normal rate before the Northridge earthquake happened," Graves said. "It means it was quiet, but it's not quiet now."
Graves said the experimental earthquake early warning system being developed by Caltech gave four seconds notice of the impending temblor.
"The system worked as it was supposed to work." Graves said.
—City News Service