Odds of major earthquake striking San Francisco Bay Area in next 30 years increasing, experts say

SAN FRANCISCO -- The U.S. Geological Survey released a new study showing the probability of a major earthquake, greater than 6.7 magnitude hitting the San Francisco Bay Area within the next 30 years has increased by about 2% to 74%.

The likelihood increased on different fault lines because more time has passed without a major quake since the last study was conducted more than a decade ago.

And that is resulting in tectonic stress build up.

"It is the longest fault in California and therefore capable of the biggest earthquakes," said Dr. Lucy Jones, USGS seismologist, referring to the San Andreas fault.

It saw the greatest percentage increase - growing by 3.6% since the last study.

But the Hayward-Rogers Creek fault is where we see the highest chance of a major earthquake with the probability sitting at 34.3%.

Even with the increased risk, Dr. Jones says earthquakes remain unpredictable.

"It could go another hundred years, it could be tomorrow. It could be, you know, next minute," she said.

The Hayward-Rogers Creek system is located beneath densely populated communities in the East Bay - from Fremont through Hayward, Oakland and north toward Santa Rosa.

An absolute worst case scenario for the Bay Area would be if there was a linked rupture between the Hayward and Rogers Creek faults - potentially generating a 7.4 magnitude earthquake.

East Bay residents got a reminder of that in August when a small, but strong quake struck under the Oakland Zoo in August.

"And just everything started shaking, and I was like, wait. I jumped up and ran out, and I was like, was that an earthquake there? Like, yeah. And then my nephew, he's two and a half. He was like, that was a big one," said Caitlin Fitzpatrick, who felt the Oakland earthquake.

"We underestimate the social disruption and the economic disruption. We are so focused on our fear of dying, that we forget to be afraid of being bankrupted," Dr. Jones said.