MENLO PARK (CBS SF) — A significant aftershock from last weekend’s magnitude-6.0 earthquake has rattled the Napa Valley.

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.

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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.

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The USGS reported a minor 2.5 magnitude earthquake Sunday at 6:37 a.m. in Green Valley, about seven miles east-southeast of Napa.

No additional damage or injuries were reported.

The USGS says there have been more than 70 aftershocks recorded since last Sunday’s earthquake.

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