A magnitude 3.7 earthquake shook Hayward, Calif., just before 2 p.m. Thursday, according to the U.S. Geological Survey.
The temblor followed three earlier small earthquakes. The epicenter for each was about one mile east of the city in San Francisco’s East Bay, the agency said.
At 5:03 a.m., a magnitude 2.7 quake struck near the Hayward fault, followed at 11:52 a.m. by a 3.3 quake, then a 3.2 earthquake at 11:54 a.m. The fourth, at magnitude 3.7, was recorded at 1:59 p.m.
The first quake occurred at a depth of about 3.3 miles; the second, 3.5 miles; the third, 3.8 miles; and the fourth, 4.4 miles.
About 4,000 people reported feeling the latest quake, according to the USGS.
Light shaking was felt around Hayward. Residents in Vallejo to the north and Sunnyvale and San Jose to the south reported weak shaking.
Previous reports from the USGS have noted the danger posed by the Hayward fault, which is lesser known than the San Andreas fault. The Hayward fault runs under the East Bay but poses significant risk, the agency said in a 2018 report.
The Hayward fault is particularly dangerous because it runs through some of the most heavily populated parts of the Bay Area, spanning the length of the East Bay from the San Pablo Bay through Berkeley, Oakland, Hayward, Fremont and into Milpitas.
An average of 234 earthquakes with magnitudes between 3.0 and 4.0 occur per year in California and Nevada, according to a recent three-year data sample.
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Quakebot, a computer application that monitors the latest earthquakes detected by the USGS, contributed to this article. If you’re interested in learning more about the system, visit our list of frequently asked questions.
Times staff writer Ron-Gong Lin II contributed to this report.
