A magnitude 4.1 earthquake struck the southwest region of Sacramento County near Contra Costa, Solano and San Joaquin counties early Wednesday, the U.S. Geological Survey said.
The earthquake was reported at 9:29 a.m. and triggered an early warning, which was sent widely to cell phones throughout Northern California. The Earthquake Early Warning System can send alerts through the MyShake app, as well as through the Android operating system and an Amber Alert-like system; a testing exercise on the application is planned for Thursday at 10:19 a.m., International Shake-Off Day.
Many people living in the more populated areas of the San Francisco Bay Area and Sacramento region were not shaken by Monday’s earthquake. The strongest shaking, felt near the epicenter, was light, according to the U.S. Geological Survey, just enough to shake dishes.
The preliminary epicenter in the southwest tip of Sacramento County was about four miles southeast of Rio Vista, a city in eastern Solano County, and about 16 miles northeast of Oakley and 13 miles northeast of Antioch, which are in Contra Costa County.
In the past 10 days, there have been two earthquakes of magnitude 3.0 or greater centered nearby.
On average, 25 earthquakes ranging in magnitude from 4.0 to 5.0 occur each year in California and Nevada, according to a recent three-year data sample.
The earthquake occurred at a depth of 6.7 miles. Did you feel this earthquake? Consider reporting what you felt to the USGS.
Find out what to do before and during an earthquake near you by subscribing to our Unshaken newsletter, which breaks down emergency preparedness into small steps over six weeks. Learn more about seismic kits, the applications you need, Lucy Jones’ most important tips and more at latimes.com/Unshaken.
An early draft of this story was automatically generated by Quakebot, a computer application that monitors the latest earthquakes detected by the USGS. A Times editor reviewed the post before publication, and then a Times editor updated the article. If you want to know more about the system, check out our list of frequently asked questions.