California’s earthquake yesterday was the strongest to hit the region in 20 years. The intense 6.4 magnitude quake struck just after 10.30am local time (6.30pm BST) on Thursday, July 4, near the town Ridgecrest in California, around 150 miles northeast of Los Angeles. A wave of fires and dozens of aftershocks have since occurred in the area, but experts have now warned than an even bigger seismic event may strike the USA state in the next few days. Now, a massive 5.4 magnitude aftershock has jusr hit the region – but how many more quakes have hit California since the big one and how many aftershocks are expected?
The massive earthquake with a magnitude of 6.4 hit southern California at 10.34am yesterday.
The epicenter of the quake was located in a remote area of the Mojave Desert, but the shakes were felt by residents across much of Southern California.
The nearest largely populated area is Ridgecrest with a population of circa 28,000 people.
Millions of the members of the public in Southern California, including Ridgecrest, Los Angeles and Las Vegas areas reported feeling the temblors.
California earthquake today: Have more earthquakes hit California today? (Image: MARIO TAMA/GETTY/USGS)
It was even felt in Mexico, where buildings were evacuated in Tijuana and Mexicali.
According to European earthquake agency EMSC, around 20 million people who live in the area were impacted by the quake.
This event has triggered a number of aftershocks, which will typically decrease in frequency over time.
On average, a 6.4 magnitude earthquake will produce an aftershock as large as 5.4 followed by around 10 aftershocks with a magnitude of 4.4 or higher.
California earthquake today: USGS Map shows shaking from the July 4 southern California quake (Image: USGS)
According to USGS Seismologist Robert Graves, at least 180 aftershocks of magnitude 2.5 or greater were recorded after the earthquake.
This figure is higher than the usual number, but is not unprecedented according to Mr Graves.
The largest that was recorded was a magnitude of 4.6.
Earthquakes of this size can cause damage, particularly close to the rupture and those above a magnitude of 3 can be felt near the epicenter.
California earthquake today: Temblor map of the main shock and its first two hours of aftershocks (Image: TEMBLOR)
USGS estimates a nine percent chance of one or more aftershocks of magnitude 6.4 or larger in the next week.
The Californian earthquake caused multiple injuries and two house fires which were reported in town, with emergency services dispatched to deal with gas leaks and reports of cracked roads.
A state of emergency was yesterday declared in California’s Kern County and people in Ridgecrest Regional Hospital were evacuated.
Seismologist Lucy Jones said the quake was on a “strike-slip fault” about 10 miles from Ridgecrest and not on the dangerous San Andreas fault.
California earthquake today: Seismologist Lucy Jones speaks at a media briefing after the 6.4 quake (Image: ROBYN BECK/AFP/GETTY)
But she warned that more earthquakes, including potentially larger and more intense ones, were likely.
Dr Jones told the LA Times: “This does not make [the big one] less likely.
“There is about a one in 20 chance that this location will be having an even bigger earthquake in the next few days, that we have not yet seen the biggest earthquake of the sequence.”
According to the USGS, 173 earthquakes, including the 6.4 magnitude quake, were recording throughout the day in California.
California earthquake today: California earthquake forces hospitals to evacuate patients (Image: IRFAN KHAN/LOS ANGELES TIMES/GETTY)
Out of those, 170 of them occurred in the vicinity of Ridgecrest and 167 occurred after the 6.4 magnitude earthquake.
US President Donald Trump tweeted after the quake hit.
He wrote: “Been fully briefed on earthquake in Southern California. All seems to be very much under control.”
The quake was the strongest in southern California since a 7.1-magnitude event, dubbed the Hector Mine quake, in 1999.
Fears of a large earthquake had grown recently after 1,000 small tremors were recorded in Southern California over a period of three weeks.