An earthquake east of downtown Los Angeles rippled across Southern California before dawn Tuesday, jolting millions of people awake and putting first-responders on alert.
There are no reports of damage, injuries or power outages linked to the temblor.
"All is calm in the city of Los Angeles," Los Angeles Fire Department Capt. Steve Ruda said.
Nearly an hour after the quake, the California Highway Patrol got reports of a buckled 10-foot stretch of concrete in a center lane of southbound Interstate 5 south of downtown in the Downey area, The Associated Press reported.
According to Reuters, it hit at 4:04 a.m. local time (1104 GMT) and lasted a few seconds, rousing many from their beds and prompting local television stations to issue bulletins. The quake was at a depth of nearly 11 miles on the Whittier fault.
Home to 10 million people, Los Angeles County had its last strong earthquake in Northridge in 1994, which killed some 60 people.
According to a report in Inland Empire News, seismologist Dr. Kate Hutton at Cal Tech says it’s all in the numbers.
"The 5 percent probability is based on statistics of past earthquakes. If we look at all the earthquake we’ve ever had in Southern California, 5 percent of them are followed by something larger."