A series of earthquakes has shaken Southern California, with the latest tremor marking the fourteenth in less than 24 hours. Experts caution that additional seismic activity could be forthcoming.

The most recent earthquake occurred just a few miles from Indio in the Coachella Valley, situated approximately 100 miles east of Los Angeles and San Diego.

According to the US Geological Survey (USGS), this quake registered a magnitude of 3.6 and struck at 1:48 PM ET on Tuesday. It happened along the Mission Creek strand, a segment of the notorious San Andreas Fault.

The seismic swarm began shortly before 9 PM ET on Monday, when a more powerful 4.9 magnitude earthquake was recorded in the same vicinity.

Tuesday afternoon’s quake was among over a dozen perceptible aftershocks that have impacted this densely populated region within a span of just 16 hours.

The initial earthquake reportedly produced significant shaking at its epicenter near Indio. Thousands of residents, from the epicenter to the US coastline, reported the tremors to the USGS, affecting more than five million people across Los Angeles and San Diego.

The day-long swarm has been taking place just 15miles from the site of the annual Coachella music and arts festival, which brings roughly 250,000 people to the area in April.

USGS officials have warned that there is a 98percent chance of more earthquakes stronger than 3.0 in magnitude hitting the region over the next seven days, and a 39percent chance those aftershocks will exceed magnitude 4.0.

A magnitude 4.9 earthquake struck Southern California at 9pm ET on Monday, starting a swarm of over a dozen tremors in less than a day

The earthquake swarm broke just over 100 miles from Los Angeles, home to nearly four million people (Stock Image)

Since Monday night’s magnitude 4.9 quake, USGS has registered over 150 seismic disturbances in the Coachella Valley.

The majority of those tremors registered under magnitude 2.0, making them almost too weak for people to feel at ground level.

However, over 12 have fallen between magnitude 2.5 and 4.9, meaning residents likely felt some considerable shaking during the quakes but no severe damage was caused. No injuries have been reported.

While this week’s swarm has spared locals from any major damage, fears continue to grow about the future stability of the San Andreas and other major fault lines in California.

The San Andreas is an 800-mile-long fault line running from Southern California, through the Bay Area, and all the way into the northern part of the state and Pacific Ocean.

A recent 2021 study in Science Advances concluded that the southern part of the fault has been quietly storing a huge amount of stress for centuries.

When it finally snaps, just like a rubber band breaking, scientists have theorized it could release all that built-up energy in one major event, potentially causing a very large earthquake on the Mission Creek strand.

According to a 2015 report by USGS scientists, there is a 95percent probability that at least one major quake, stronger than magnitude 6.7, will strike somewhere in the region by 2043. 

The earthquake swarm in Southern California broke out along a section of the San Andreas Fault called the Mission Creek strand

USGS’s earthquake forecast predicted that this impending earthquake had a 72percent chance of striking right in the San Francisco Bay Area, home to approximately eight million people.

Overall, the grim report estimated that there was more than a 99percent certainty that a major quake over magnitude 6.7 would erupt somewhere in the state, including Southern California, closer to Los Angeles and San Diego.

Scientists previously believed most of the sliding action in Southern California, where the two huge pieces of Earth’s crust grind past each other, was happening along other branches of the San Andreas, like the Banning strand. 

However, the 2021 report discovered that the Mission Creek strand, the section running through the Coachella Valley, was actually the main driver of seismic activity in this part of Southern California.

Researchers in California found Mission Creek handles most of the sideways sliding between the Pacific Plate and the North American Plate, covering about 90percent of the total sliding movement in this part of California.

In 2008, officials with USGS conducted a simulation of what a 7.8 magnitude quake would do if it erupted along the San Andreas fault under Los Angeles.

This hypothetical ‘Big One’ would cause roughly 1,800 deaths, 50,000 injuries, and $200 billion in damages, according to the Great California ShakeOut.

It would also cause a surface rupture of up to 13 feet, causing significant damage to infrastructure crossing the fault line, such as roads, pipelines, and rail lines.

As for buildings, roughly two million buildings would be affected, with 50,000 buildings completely destroyed or red-tagged, meaning they couldn’t house people again.

The report also warned that older, unreinforced structures and high-rises with brittle welds were particularly vulnerable.