California earthquake: Aftershocks rattle Napa Valley during recovery

While some businesses in and around Napa, California, emerged unscathed from Sunday's 6.0 quake, Vintner's Collective was hit hard. (AP Photo/Noah Berger)

NAPA, Calif. (AP) - The Napa Valley has been rattled by a small aftershock to the strong and damaging earthquake that hit California's wine capital over the weekend.

The US Geological Survey says the 3.9-magnitude quake struck at 5:33 a.m. Tuesday about 7 miles south of the city of Napa.

There were no calls reporting damage or injuries, but the quake did rattle already frayed nerves.

"That's not just an aftershock. That's another earthquake to me," Krisha Reed said after running out of her apartment.

She had suffered injuries in Sunday's 6.0-magnitude earthquake, which is estimated to have caused at least $1 billion in property damage in California's wine country.

There have been a series of small aftershocks, mostly in the 2.0-magnitude range.