California could be hit by another, even more powerful earthquake within days after southern California was rocked by its worst tremor in 20 years on Thursday, experts believe.
Geologists say yesterday’s 6.4-magnitude quake is likely to produce a forceful 5.5-strength aftershock and a series of smaller tremors – and could even prompt a larger one.
In addition, officials admitted that a new Los Angeles earthquake warning app had not sent out a public alert despite the most powerful Southern California quake since 1999.
The ShakeAlert system detected the quake but did not trigger a public warning because the magnitude was less than 5.0 in Los Angeles, city bosses said.
The Fourth of July quake cracked roads, caused fires and broke power lines, although there were no serious injuries reported.
Today residents in the small desert city of Ridgecrest were set to begin the clean-up while two houses were damaged by fire from broken gas pipes.
The quake also drew the attention of a series of California-based celebrities, including Trevor Noah, Ashley Tisdale, and Ava DuVernay, who said: ‘That was the longest earthquake I’ve ever experienced.’
Speaking to SFGate, U.S. Geological Survey expert Susan Hough said: ‘For a 6.5 quake you’d expect a lot of aftershocks. You’d expect the biggest to be 5.5 and so far the biggest has been 4.7.
‘With any earthquake, there is a 5 percent chance something even bigger will happen within the next three days. If it did, it would be in the same remote area.’
Los Angeles city bosses have promised to revamp the ShakeAlert system after residents did not receive a notification about the quake.
‘The ShakeAlert app only sends alerts if shaking is 5.0+ in LA County. Epicenter was 6.4 in Kern County, USGS confirms LA’s shaking was 4.5,’ a statement said.
‘We hear you and will lower the alert threshold.’
ShakeAlert detected the quake, giving 48 seconds of warning to the seismology lab before the shaking arrived in Pasadena.
Officials in San Bernardino County said the quake caused water mains to break, downed power lines, cracked buildings and caused rock slides on roads.
At least four large aftershocks have been recorded, measuring 4.7, 3.5, 3.8 and 4.2 magnitude, officials said.
President Donald Trump said he was fully briefed on the earthquake and that it ‘all seems to be very much under control’.
Several celebrities also tweeted about the quake.
Actress Gabrielle Union tweeted that the she was using the bathroom at the time of the earthquake.
‘The fact that I experienced that longa** earthquake while on the toilet at the gym…and immediately blamed the celery juice, is about right. Lordt,’ she joked.
Ava DuVernay also tweeted: ‘Been living in Los Angeles all my life. That was the longest earthquake I’ve ever experienced. Not jerky. Smooth and rolling. But it was loooong.
‘It was so long I thought for the first time ever ‘Is this the big one?’ Damn. Respect Mother Nature. She’s the boss.’
Trevor Noah said: ‘That earthquake was not fun…’
‘6.6 is strong. We felt a lil’ movement here in the valley, but all good. Prayers to those in D valley, Bakersfield, S Valley, Kern etc. Be safe, stay prepared,’ Dwayne ‘The Rock’ Johnson tweeted.
The Los Angeles Airport said that all of their ‘runways have been inspected with no reported damage to the airfield or the Sepulveda tunnel. Operations remain normal’.
Video posted online of a liquor store in Ridgecrest showed the aisles filled with broken wine and liquor bottles, knocked down boxes and other groceries strewn on the floor. Flames were seen shooting out of one home in the community.
Another video shows the moment the quake even created waves in a resident’s swimming pool.
Cora Burke, a waitress at Midway Cafe in Ridgecrest, said: ‘It almost gave me a heart attack.’
‘It’s just a rolling feeling inside the building, inside the cafe and all of a sudden everything started falling off the shelf, glasses, the refrigerator and everything in the small refrigerator fell over.’
Ashleigh Chandler, a helicopter rescue EMT at Fort Irwin, California, said the quake happened as she was getting ready for a July 4th party.
‘I was just in the living room getting everything ready, we start to feel the shaking, so then I look up and then the wine bottles start rattling and I thought, ‘They’re going to fall.’
‘My sister was in the house and my dog, so we just got everyone outside and then it ended. It was like 15, 20 seconds, maybe. It was pretty good shaking, so I’m out of breath.
Lucy Jones, a seismologist with the California Institute of Technology’s seismology lab, said the earthquake was the strongest since a 7.1 quake struck in the area on October 16, 1999.
‘This has been an extremely quiet abnormal time,’ Jones said. ‘This type of earthquake is much more normal … The long term average is probably once every five or 10 years somewhere in Southern California.’