Six minor earthquakes rattled parts of the South Bay on Thursday, according to the U.S. Geological Society, and three of them were strong enough to be felt across the region.
The first two larger quakes occurred within a two-hour span in the morning and a third about 6:20 p.m.
The third temblor, a magnitude 3.3, was cenetered about 2 miles north of the East San Jose foothills, the USGS said.
The first quake, a magnitude-3.3, occurred at 10:32 a.m. Its epicenter was less than 2 miles north of the eastern foothills of San Jose, 3 miles northeast of Alum Rock and 5.1 miles southeast from Milpitas, the USGS reported.
Another quake, a magnitude-2.6, was felt in the same area around 12:30 p.m.
All of the earthquakes occurred on the Hayward Fault, the USGS said. There's nothing unusual about the quakes, the agency said, even though all five were in the same area.
"They're good kind of earthquakes to have," geophysicist Brian Kilgore said. "They're large enough to be felt but not so large to cause damage. They are a terrific reminder to think about your personal earthquake plan.
Neither injuries nor damage were reported in the morning temblors, but some people in San Jose said they felt the quake.
Kruthi Vishwanath told NBC Bay Area that she lives near Berryessa and felt "vivid tremors."
"My laptop and printer at home, shook. Scary!!" she wrote.
Suzanne Hughes wrote on Facebook that she experienced a "jolt," after which a table and plant shook, and she "knew it was an earthquake right away."
Locations where people experienced the earthquake include the Matrix Casino, 8x8, Inc. and Cisco headquarters, Vinci Park Elementary School and the Evergreens area of San Jose. Tremors were felt as far away as Sunnyvale, where Marianne Bettio's "computer monitor shook on the desk," and in Milpitas.
The USGS said it's nearly impossible to tell if a quake is a foreshock before a bigger earthquake but added that foreshocks are very rare.