A set of aftershocks that rattled the Bay Area Tuesday morning caused damage to the George Butler Bridge in Napa, officials said.
Crews with the California Department of Transportation were performing emergency road repair on the bridge on southbound State Route 29 after a "deviation" or bump was found, said Sgt. Diana McDermott of the California Highway Patrol.
Motorists, she said, can feel the bump in the bridge as they drive over it. No collisions were reported, she said. Crews closed one lane of the two-lane road to make the repairs.
The series of aftershocks began early Tuesday with the largest at magnitude 3.9 a mile from American Canyon at a depth of 6.8 miles.
The aftershocks came as the U.S. Department of Transportation's Federal Highway Administration announced Tuesday it planned to make $2 million in emergency relief money immediately available to Caltrans and local agencies to pay for roadway damage caused by Sunday's 6.0-magnitude earthquake.
Bridges and highways suffered surface cracks and quake damage; preliminary estimates indicate repairs will total at least $10 million.
Widespread crackling was spotted on State Route 121 just north of the Napa-Sonoma county line. "Significant stress" to joints was also discovered on bridges, including the Napa River Bridge on State Route 29.