A growing body of research is raising alarms about seismic risks in California, with scientists warning that a powerful earthquake could strike a densely populated region with little warning.
According to the New York Post, a recent study published in Seismological Research Letters points to the Hayward Fault as a major concern, suggesting the fault may be overdue for a significant rupture.
Researchers say such an event could “cause extensive damage to such a dense population zone,” highlighting the potential consequences for millions living in the area.
The Hayward Fault runs roughly 74 miles through the San Francisco Bay Area, cutting across major cities including Berkeley, Oakland, and Fremont. Altogether, about 8 million people live along or near the fault.
Part of the larger San Andreas Fault system, the Hayward Fault has a history of producing earthquakes around magnitude 7 — events capable of widespread destruction.
The last major rupture occurred in 1868. Scientists estimate that earthquakes along this fault typically happen every 95 to 183 years, placing the region within a window where another event is increasingly likely.
According to the U.S. Geological Survey, there is a 14.3% chance of a magnitude 6.7 or greater earthquake by 2034 and a 33% chance before 2043.
“This fault is what we sort of call a tectonic time bomb,” said David Schwartz in a previous statement. “It’s just waiting to go off.”
To better understand the threat, scientists from Lawrence Livermore National Laboratory and Lawrence Berkeley National Laboratory conducted advanced simulations, modeling 50 potential magnitude-7 earthquakes along the fault.
Their findings suggest that ground shaking in some areas could be up to 50% stronger than earlier estimates.
“We are interested in learning what the ground motion for a typical magnitude-7 earthquake in the Bay Area could be, so that we can work with engineers to make sure that the infrastructure and buildings in the Bay Area can withstand this motion,” said researcher Arben Pitarka.
The simulations also identified specific regions that could experience especially intense shaking, including cities such as Livermore, Hayward, and San Leandro.
Experts say certain geological features could amplify the impact. Basin areas, including the Livermore Basin and low-lying Bay Mud regions, may trap seismic waves and increase both the intensity and duration of shaking.
Previous projections from the USGS, known as the “HayWired Scenario,” estimate that a major quake could result in hundreds of deaths, tens of thousands of injuries, and widespread destruction, including fires and displaced residents.
Researchers say these models are not just predictions, but tools to help communities prepare.
“With that information, we can also start preparations for retrofitting some of the vulnerable structures,” Pitarka said.
Scientists plan to apply similar simulations to other nearby faults, including the San Andreas, in an effort to better understand and prepare for future seismic threats.
