Aug. 24 (Bloomberg) -- A 6.1 earthquake, the strongest in northern California in 25 years, rocked the state’s wine-country region early today, damaging historic buildings and sending residents scurrying from their homes.
The quake in the Napa-Sonoma County region was reported at 3:20 a.m. local time and its epicenter was 51 miles (82 kilometers) southwest of Sacramento, the U.S. Geological Survey said in a statement on its website. The temblor was the strongest since the 6.9 Loma Prieta earthquake of 1989.
KGO-TV in San Francisco said 70 people were injured and being treated at a hospital in Napa. In the city of Napa, unreinforced masonry buildings in downtown, including its historic courthouse and Goodman Library, suffered “major damage.” Power was out, and fires were reported in north Napa, along with many waterline breaks, the city said in a posting on its website.
The Napa-Sonoma area is home to one of California’s best- known wine-growing regions. Napa County has 789 licensed wineries which had sales of $5.5 billion in 2011, according to the Napa Valley Vinters, a trade association.
“This quake definitely has the potential for damage and some casualties,” said Wendy Baldwin, a geophysicist with the U.S. Geological Survey in Golden, Colorado, in a telephone interview.
Aftershocks with a magnitude of as strong as 3.6 were recorded a couple hours after the quake, the USGS said.
In Sonoma County, some residents were sent fleeing from their homes, the Associated Press reported. Camille Freking, speaking from Hercules, California, told CNN residents there felt a rolling sensation that lasted about 30 seconds when the quake struck.
More than 51,000 homes and businesses were without power, according to PG&E Corp.’s website. The communities hardest hit were Napa and Sonoma, the company said.
California Governor Jerry Brown said in a statement today the state’s Office of Emergency Services is working with local and state emergency managers in the area.
The USGS’s Baldwin said the temblor was the strongest to hit the Bay Area since the Loma Prieta quake that struck during a World Series game between the Oakland Athletics and San Francisco Giants. She said there was a similar magnitude event of 5.8 in 1980 that struck 45 miles southeast of the current epicenter.
Baldwin said aftershocks will occur for several weeks. She said there is a 5 percent to 10 percent chance that an aftershock could reach magnitude 5 or greater.
The USGS said today there was a “low likelihood” of casualties and put out an orange alert for economic losses, which means “significant damage” is likely and the disaster may be widespread. The quake’s depth was 6.7 miles, the USGS said.
The California Highway Patrol in San Francisco said there was no reported road damage in Marin and Santa Rosa. It didn’t have any immediate reports of damage to roads in South Bay, the Peninsula and East Bay, according to Twitter postings.