4.5 Magnitude Earthquake Shakes Stanislaus County
Westley, CA – On Monday evening, residents of Stanislaus County experienced a rare earthquake measuring 4.5 magnitude, the largest in a century, according to US Geological Survey records. The quake occurred near Westley at 9 p.m., catching many off guard and raising concerns about future seismic activity.
USGS research geologist, Austin Elliott, reassured residents that although this earthquake was significant, it does not necessarily indicate a larger event is imminent. “No individual small earthquake inherently indicates anything larger is coming, and most earthquakes of this magnitude pass without further events and without further larger events,” Elliott stated.
While aftershock sequences following earthquakes can last for weeks or months, Elliott explained that aftershocks from a 4.5 magnitude earthquake are generally small and diminish over time. Residents may stop feeling aftershocks after just a few days.
The Central Valley, including Turlock, Modesto, and Patterson, felt the impact of the quake, surprising many individuals who are not accustomed to such seismic activity in the area. “A lot of the people who felt these ones are living in the Central Valley…probably not so used to having an earthquake occur so close to them,” Elliott said.
Elliott attributed the earthquakes to a combination of compressional convergent faulting and strike-slip faulting. While there are known faults in the region, the earthquakes were too small to pinpoint on a specific fault. Elliott noted that the fault structures responsible for these earthquakes may not be mapped.
The region surrounding Stanislaus County has both strike-slip and convergent faults. The San Andreas and Calaveras faults lie to the west of the county, while convergent faults are found on the eastern margin of the Central Valley. These fault systems are known to produce more frequent earthquakes compared to the faults in the area surrounding Stanislaus County.
“Earthquakes of this magnitude – twos and threes and fours – that may be happening, there are all kinds of little fractures and faults that are possible to produce small earthquakes,” Elliott explained.
Despite the rarity of this seismic activity, residents are encouraged to remain vigilant and prepare for future earthquakes. The USGS and local authorities will continue to monitor the situation and provide updates as necessary.
For further information or inquiries, please contact Clare Fonstein via email: [email protected].