The Hayward Fault, spanning from San Pablo Bay to Fremont in California’s San Francisco Bay Area, is now expected to produce a major earthquake, scientists from the US Geological Survey claim. A relatively minor 4.0-magnitude quake rattled the city of Fremont Tuesday night.
The smaller quake struck at 2:41 AM a mile and a half northeast of Fremont, according to USGS. The epicenter was at a depth of about 5 miles. It didn’t cause any serious damage, but residents reported that over a dozen aftershocks and smaller quakes could be felt in the hours that followed, which scientists estimated at magnitudes ranging from 1.0 to 2.7 on the Richter scale.
Scientists warn that a new, potentially deadly quake may strike such populous areas as Berkeley, Oakland, Hayward and Fremont, and all residents should be prepared.
“We keep a close eye on the Hayward Fault because it does sit in the heart of the Bay Area and when we do get a big earthquake on it, it’s going to have a big impact on the entire Bay Area,” said Tom Brocher, a research geophysicist with USGS.
The last time the fault produced a big quake was in 1868, when a 6.8-magnitude temblor resulted in the deaths of about 30 people, mostly residents of the city of Hayward.
“The past five major earthquakes [on the fault] have been about 140 years apart, and now we’re 147 years from that 1868 earthquake, so we definitely feel that could happen any time,” Brocher added.
Brocher clarified that the probability of a major quake isn’t connected to the one that took place on Tuesday. And experts from the California Institute of Technology confirmed that "foreshocks cannot be positively identified as foreshocks until after the mainshock has occurred."