Big earthquake on Hayward Fault could cause damage similar to 1989 Loma Prieta quake, experts warn

SAN FRANCISCO (KRON) — Thursday’s 3.1 magnitude earthquake was the latest of five notable aftershocks to hit Berkeley since a 4.3 magnitude earthquake rattled the college town on Sept. 22.

A day later, the Bay Area remembers the deadly Loma Prieta earthquake, a 6.9 magnitude quake on the San Andrews Fault, which rocked the Bay Area on Oct. 17, 1989. The earthquake killed 63 people and caused more than $10 billion in damage to the region.

The 1989 Lome Prieta quake lasted roughly 20 seconds and was followed by a 5.2 magnitude aftershock minutes after the initial rumble. Hundreds of aftershocks shook the Bay Area for weeks after the disaster.

The recent Berkeley quakes all occurred on the Hayward Fault Zone, which runs parallel to the San Andreas along the East Bay Hills from the northern end of San Jose to San Pablo Bay. This fault is capable of producing earthquakes equally destructive as the ‘89 quake, Amy Williamson, a research scientist at the Berkeley Seismological Laboratory, told KRON4 News.

Seismologists predict that the Hayward Fault has a 33% chance of generating a magnitude 6.7 earthquake or greater before 2043.

“[The Hayward Fault’s] last major earthquake occurred on Oct. 21, 1868, destroying downtown Hayward, killing 5 people and injuring 30,” according to a blog from UC Berkeley’s Seismology Lab. “With an estimated magnitude of 6.8, it caused damage throughout the area. San Francisco alone suffered $350,000 in property damage. It was considered the “Great Earthquake” until 1906.”

The next big earthquake could hit the Bay Area at any time, and seismologists can’t predict exactly when the disasters will occur.

“While scientists can generate long-term forecasts, like the one above, we unfortunately cannot predict when the next major earthquake will happen on the Hayward,” Williamson said. “That is why we always want to focus on earthquake preparedness: knowing what to do during an earthquake — drop, cover, and hold on — and to have an emergency kit at home.”

The USGS and California’s Office of Emergency Services offer extensive resources for earthquake preparedness. The San Andreas and Hayward faults present the largest threats to the Bay Area and are capable of causing significant ground shaking, liquefaction, landslides, and surface fault rupture, according to the Office of Emergency Services.

“The probability for an earthquake is highest for the Hayward Fault,” OES’s Bay Area earthquake plan reads. “An earthquake along this fault would cause significant loss of life and injuries and extensive damage to homes, businesses, and infrastructure, such as transportation and utility systems. Several hundred thousand people would likely be homeless after such an earthquake. While the Northern San Andreas Fault has a lower likelihood of generating an earthquake, this fault was responsible for the M7.8 San Francisco earthquake in 1906.”

The USGS’s handbook for earthquake preparedness in the Bay Area recommends numerous tips for earthquake safety, including having a disaster supply kit and holding at-home earthquake drills.

“This handbook provides information about the threat posed by earthquakes in the San Francisco Bay region and explains how you can prepare for, survive, and recover from these inevitable events,” the USGS handbook reads. “If you live or work in the region, you need to know why you should be concerned with earthquakes, what you can expect during and after a quake, and what you need to do beforehand to be safe and reduce damage.”