The National Weather Service (NWS) has verified that California was struck by 13 earthquakes within a mere 25-minute period overnight.
The initial quake occurred shortly after midnight on Monday, hitting northwest of El Centro, located in the southern border region.
With a magnitude of 4.8, the first quake reportedly shook much of San Diego County, according to the United States Geological Survey (USGS).
Just six minutes later, a 4.5 aftershock rattled the area, followed by several smaller aftershocks originating west of the Salton Sea.
Meteorologists attribute the quakes to the San Jacinto fault system, one of the most active faults in southern California.
The main shock’s epicenter, occurring at 12:36 am on Monday, was recorded 11.7 miles deep by the USGS.
Subsequently, twelve more quakes followed, triggering a USGS shake alert system activation.
The #ShakeAlert system estimated the quake above magnitude 5.0, prompting alerts to be sent to cell phones through various partners such as @MyShakeApp, @SanDiegoCounty #ShakeReadySD, @Android, and @fema Wireless Emergency Alerts.
The NWS, sharing a quake map online, tweeted updates, noting that several small earthquakes had occurred in El Centro within 15 minutes. By 12:53 am, the count had reached 13 earthquakes.