Phones across the West lit up Tuesday evening, urging residents to 'Drop, cover, hold on' after a 4.9-magnitude earthquake struck California.

The US Geological Survey (USGS) issued the ShakeAlert shortly after the quake hit outside Susanville, California, at 9:49pm PT (12:49am ET). 

Residents reported feeling shaking across California, western Nevada, and southern Oregon, with many sharing their experiences on social media. 

One person wrote on X: 'A 5.3-magnitude quake is a serious wake-up call for infrastructure resilience in NorCal. While the ShakeAlert system is a lifesaver, we need to focus on long-term seismic safety and emergency preparedness.' 

Several Californians and Nevadans said the quake shook their homes. 

The USGS has detected at least six aftershocks, ranging from a 2.1 to 2.5 magnitude, since the larger one hit. The most recent seismic activity was reported at 12:52am PT (3:25am ET) on Wednesday.

No damage or injuries have been reported, according to the Susanville Police Department 

Susanville, home to around 18,000 people, is situated near several fault zones, including the Honey Lake and Eagle Lake faults, within the seismically active Basin and Range region. 

This area is part of the broader Walker Lane, which accommodates movement between the Pacific and North American plates, making moderate earthquakes relatively common in the region.

The quake struck at a shallow depth of 5.6 miles, which can intensify surface shaking. 

While relatively modest in magnitude, residents in Susanville and nearby communities described light to moderate tremors.

In parts of western Nevada, including Reno and Carson City, the shaking was weaker, though many locals still received phone alerts. 

Moderate to strong shaking was also recorded in several cities, including  Sacramento, Camino, Pollock Pines, South Lake Tahoe and Malin.

One resident shared on X: 'I felt it in Westwood. My family in Paradise felt it, too. We all got the alerts.' Another described it as 'quite a jolt.'

Another shared on Facebook: 'The house started shaking, then the phones went off. Lasted a few seconds, definitely longer and stronger than the last one.'

'This one scared me pretty bad, it had the house shaking, not just the walls but actually moving,' a Facebook user posted online.

The USGS noted that there is a 60 percent chance of a 3.0-magnitude or higher aftershock in the coming week and a 16 percent chance of another 4.9-magnitude quake. 

More than 1,200 people submitted shaking reports to the agency, helping scientists map the tremor's impact.

The seismic activity in Northern California follows hundreds of earthquakes detected in San Ramon, located in the East Bay.

As of last week, the USGS detected more than 300 earthquakes near San Ramon, which sits on top of the Calaveras Fault, an active branch of the San Andreas Fault system.

The Calaveras Fault is capable of producing a magnitude 6.7 earthquake, which would impact millions of people in the San Francisco Bay Area. 

The USGS  estimates there is a 72 percent chance of this happening by 2043.

The earthquakes began on November 9 with a 3.8 magnitude, and the tremors have not stopped since. The latest, which hit on December 23, measured a 2.7 magnitude.

USGS research geophysicist Annemarie Baltay said she is not unusually concerned that the recent earthquakes signal anything larger on the horizon for San Ramon.

'These small events, as all small events are, are not indicative of an impending large earthquake,' Baltay told Patch.

'However, we live in earthquake country, so we should always be prepared for a large event,' she said.