California is known for having earthquakes, that's no news. But what is news is when over 600 earthquakes hit one spot.
This 'formation' of earthquakes is called a swarm, and they hit the area near the Southern Californian town of Westmorland over the past few days, as per the Southern California Seismic Network (SCSN).
Caltech and the U.S. Geological Survey (USGS) created a report that was published on Thursday, which highlighted the earthquakes' magnitudes. The smallest magnitude was 1.1, and the highest was 4.9.
Seismologist, Dr. Lucy Jones, pointed out on
that at least 45 earthquakes took place in the area in just two and a half hours on Wednesday. Jones even described the shaking phenomenon as "one of the largest swarms we have had in the Imperial Valley," which is saying a lot given Imperial Valley marks one of the most active seismic regions in Southern California.
In just 2.5hr Westmoreland swarm has had 45 quakes of M≥3.0. One of the largest swarms we have had in the Imperial Valley - and it is historically the most active swarms in SoCal.— Dr. Lucy Jones (@DrLucyJones) October 1, 2020
Swarms are known for lasting a while. The USGS wrote in the report that some past swarms have lasted up to 20 days, while the average usually last a week.
The area where the earthquakes happened is an active seismic region and is known for its swarms. This particular swarm happened in the Brawley Seismic Zone, which is an area that connects the large San Andreas fault — one of the most dangerous and active zones — to the Imperial fault.
Swarms of earthquakes can lead to one large earthquake down the line, so seismologists are keeping a close eye on the area.
You can watch the earthquakes' data below, which was captured by SCSN California: