NAPA, Calif. -

California's Napa County 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 this morning about 7 miles south of the city of Napa.

A sheriff's dispatcher says the station shook a little, but there have been no calls reporting damage or injuries.

California's wine capital is still recovering from Sunday's 6.0-magnitude earthquake, which is estimated to have caused at least $1 billion in property damage.