In California, the fifth earthquake was reported in just 48 hours, raising concerns about the cause of the series of quakes.
The magnitude 3.3 quake struck about 1:39 a.m. PST on Sunday, 32 miles (51 kilometers) southeast of Coachella.
All five quakes struck in Salton City, California, where a swarm of quakes measuring about 3.0 on the Richter scale was created, reaching El Centro, the largest city in the Imperial Valley, 42 miles away.
The area lies on the southern side of the San Andreas Fault, which poses the greatest seismic hazard in the state.
Southern California alone experiences about 10,000 earthquakes each year, and the Los Angeles area is expected to experience a magnitude 6.7 or greater earthquake within the next 30 years, according to a report from the U.S. Geological Survey (USGS).
The USGS recorded a 3.3 magnitude earthquake in Southern California on Sunday, just days after Salton City residents experienced four other quakes since Friday
In California, a 3.3 magnitude earthquake was announced, hitting Salton City and also affecting residents of Ocotillo Wells, Oasis and Borrego Springs.
Just one day earlier, the area had been hit by a 2.6 magnitude earthquake. On the same day, August 2, there were earthquakes measuring 3.4, 2.6 and 2.8 on the Richter scale.
There have reportedly been no direct damage or injuries reported as a result of the earthquakes.
This follows reports of 16 earthquakes with a magnitude of three or greater hitting the region in May.
“The current earthquakes in the Imperial Valley are called a swarm,” says seismologist Lucy Jones wrote on X. ‘These were common in the Imperial Valley.’
The Geological Survey (USGS) confirmed that the earthquake began just 3.5 kilometers below the Earth’s surface.
Normally, people only feel earthquakes with a magnitude of 3.0 or greater, but this also depends on the depth and location of the quake.
At their deepest, earthquakes can occur as much as 640 kilometers underground.
Earthquakes that reach a distance of 69 kilometers or less are considered shallow and cause only minor to moderate damage.
Scientists previously believed the quakes were caused by the Salton Sea Basin filling with water, which filled Lake Cahuilla. Both lakes are in Imperial Valley.
Researchers from San Diego State University said in a 2023 report study that as the water level in the lake rose, more pressure was put on the surrounding crust and the water retreated underground, causing the fault line to rupture and seismic activity.
Since the early 20th century, however, the basin and Lake Cahuilla have been drying up. However, a 2023 study found that while the earthquakes are smaller in magnitude, pressure on the tectonic plates continues to build, and another large earthquake could occur in the region.
Earthquakes occur when fault lines beneath the Earth’s crust shift, releasing seismic waves that shake the ground
“While the factors of the drying of the Salton Sea contribute somewhat to the stabilization of the southern San Andreas Fault, the tectonic stress caused by plate movement is considerably greater and continues to build up along the fault,” said Ryley Hill, a doctoral candidate in geophysics who studied the connection between the basin and the fault. UC San Diego.
The connection between the lake and the earthquake is caused by induced seismicity: an earthquake is caused by forces outside the normal stress interactions between the tectonic plates.
This usually happens when large reservoirs fill with water. It is also associated with hydraulic fracturing, also known as fracking, where wastewater is injected into the earth to release natural gas for energy.
“Earthquakes are more likely to occur when water is involved,” said Thomas Rockwell, a geologist at San Diego State University EOS.org.
This could be why the San Andreas Fault in California is one of the most active fault lines in the world. Thousands of earthquakes occur in the state each year, of which 500 can be felt by residents.