AMERICAN CANYON, Calif. -- A series of aftershocks from Sunday's powerful 6.0-magnitude earthquake put a lot of North Bay residents on edge Tuesday morning.
The strongest was a 3.9 magnitude earthquake that struck 1 mile northwest of American Canyon at 5:33 a.m. that was followed by several smaller aftershocks throughout the morning.
Tom Brocher with the U.S. Geological Services told us in a phone interview that it's not over yet.
"We can get stronger aftershocks," he said. "Yesterday the probability of a magnitude 5.0 was 25 percent, 1 in 4. That chance is probably even lower today, but we are going to see more aftershocks."
There were no reports of damage or injuries from the aftershocks, though they did cause some concerns along Highway 29 in Napa. Caltrans and the California Highway Patrol closed one of the two southbound lanes of Highway 29 near the Butler Bridge. Sky 7HD was overhead around 10 a.m. and footage showed inspections being done on the span.
PHOTOS: Earthquake damage around the Bay Area
Road officials said they believe there has been some settlement of the soil in the area that needs to be looked at. No damage to the highway bridge has been found yet. The CHP does not know when the lane will reopen.
In the meantime, Napa Valley remains on high alert after Sunday's historic quake. It's the biggest to hit the Bay Area since Loma Prieta struck nearly 25 years ago. City inspections are now coming to an end, with recovery expected to start Tuesday.
San Francisco Mayor Ed Lee toured the damage on Tuesday morning.
"I just want to express my support to all the residents and certainly to people working around the clock," he said.
VIDEO: SF mayor tours Napa quake damage
Beyond that, the mayor is hoping his constituents will pitch in; namely, corporate citizens. He says Napa and San Francisco are tightly linked by tourism.
"I'm going to ask volunteers, ask for donations, ask for corporate citizens to be generous in their time and resources to help people of Napa, Vallejo, and Sonoma," he said.
More than 200 people were injured, including 13-year-old Nicholas Dillon who was hit by falling debris.
"He jolted upwards to reach for his friend and yell his name," said his aunt, Carmen Rosales. "And as he was crawling away, with the shaking, the bricks fell on him. He has multiple fractures to his pelvis."
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Napa County will partially resume several public services Tuesday the first time since the quake. The Planning and Building Department will re-open at 1 p.m. in the County Administration Building on Third Street. The assessor, recorder and county clerk's office has temporarily moved to the same building and will also be open at 1 p.m. The DA's office and public defender have both moved to the main library.
Most Napa schools are closed again Tuesday, but the Napa Valley School District announced all schools have been found safe to open on Wednesday, with the exception of Stone Bridge Charter. Stone Bridge Charter is near the epicenter and suffered some major cracks that are still undergoing inspections.
Most after-school activities have been cancelled, however at Napa, Vintage and American Canyon high schools, football and cross country practices will go on as scheduled. School officials expect to announce around 1 p.m. whether classes will be held Wednesday and at which schools. However, classes did resume Tuesday at Justin-Siena High School.
At least 70 buildings in the city of Napa have been red-tagged, another 200 yellow-tagged. City officials say they expect that number to grow in the following days and weeks.
Meanwhile, the mayor of Napa is calling on assistance from FEMA to help businesses affected by the quake get back on their feet. Last night, the city began fencing off much of the downtown area so heavy machinery can start hauling away debris.
The timing of the quake was not good for Napa's famous wineries, many of which had already started this year's harvest. Owners are working quickly to clean up the massive mess, so they can continue the harvest process before it's too late. Between wineries, homes, businesses and more, Kinetic Analysis Corporation - a firm that studies natural disasters - estimates overall damages could top $4 billion.
VIDEO: Quake hits wineries; fear of price increases
Public works crews in Napa are on the job trying to repair dozens of water line breaks. They faced a total of 90 breaks. Eight were repaired last night. Anyone who lost water service completely any time after the earthquake is advised to use bottled water for drinking or cooking or boil tap water for a full minute. Some customers may have their water cut off while repairs are made nearby. The city also has two water stations, one on Pearl Street another at the Las Flores Center on Linda Vista Avenue.
The City of Napa has removed all debris boxes from Napa schools and is urging people who may be cleaning up their homes to take their debris to sanctioned sites. A list of these sites can be found on the City of Napa's website.
Bay City News contributed to this report.