NAPA, Calif. -- A significant aftershock from last weekend's magnitude-6.0 earthquake has rattled Northern California's wine country.
The U.S. Geological Survey says the magnitude-3.2 tremor struck 5 miles south of the city of Napa just before 2 a.m. Sunday.
Thomas Brocher, director of USGS' Earthquake Science Center, says it wasn't the strongest aftershock to rumble the region since the main quake a week ago caused as much as $1 billion in damage and multiple injuries.
A magnitude-3.9 aftershock centered 8 miles south of Napa hit early Tuesday morning.
The USGS says there have been more than 70 aftershocks recorded since last Sunday's earthquake.
No additional damage or injuries have been reported.