SAN FRANCISCO –
A 5.1 magnitude earthquake rocked the San Francisco Bay Area on Tuesday, delaying some commuter trains. No reports of damage or injuries.
The United States Geological Survey said the 11:42 a.m. quake was centered 12 miles (19 km) east of San Jose at a depth of about 4 miles (6 km). The area is hilly land about 40 miles (64 km) southeast of downtown San Francisco.
Lucy Jones, a veteran California seismologist, told KNTV-TV that the quake was caused by the Calaveras fault, one of eight major faults in the Bay Area.
“The Calaveras Fault tends to have smaller earthquakes,” says Jones.
Jones said it was the largest quake in the Bay Area since a 6.0 magnitude earthquake hit the wine-producing nation of Napa in 2014.
The 138-mile (220 km) Calaveras Fault is a major tributary of the San Andreas fault and runs from San Juan Bautista in the south to San Ramon in the north, Jones said.
Many moderate earthquakes have occurred along the Calaveras fault, including the 6.2 Morgan Hill quake in 1984, Annemarie Baltay, a seismologist with the US Geological Survey, said in a statement. video claims posted on Twitter.
Rich Constantine, the mayor of Morgan Hill, a city next to San Jose, said he was in the kitchen of his home when Tuesday’s “long and steady” quake struck.
“We had a falling frame, everything shook but once it stopped, there was no damage,” he said.
Constantine said Morgan Hill’s City Hall and other city offices were evacuated but people were back to work shortly after.
People said they felt the quake as far south as the beautiful Big Sur coast, 75 miles (120 km) south of the epicenter in the Joseph Grant Ranch County Park area, an area vast nature.
Nearly 100,000 people said they received a warning before the shaking started through California’s earthquake early warning system, according to the California Governor’s Office of Emergency Services, or Cal OES.
“Advance notice varies from two seconds for those very close to the epicenter to 18 seconds for those in San Francisco,” the agency said.
MyShake, a statewide mobile app that went public in late 2019, is based on an earthquake detection and notification system developed by the U.S. Geological Survey and its partners.
According to the United States Geological Survey, a 3.1 aftershock occurred about five minutes later.
Several commuter train companies, including Cal Train and the Bay Area Rapid Transit system, known as BART, have organized trains to check for damage. BART returned to normal operations in the early afternoon.