New 2026 USGS Data: Bay Area Earthquake Odds Just Rose to 74%

If you live or work anywhere in the San Francisco Bay Area, earthquakes are already part of the calculus of owning property here. What changed this month is the math itself. On September 2, 2026, the U.S. Geological Survey released an updated calculation of the odds of a major earthquake striking the Bay Area in the next 30 years, and the number went up, not down.

The New Numbers

USGS now puts the probability of a magnitude 6.7 or larger earthquake somewhere in the Bay Area at 74% over the next three decades, up from the 72% figure researchers had relied on since 2014. Broken down by fault, the Hayward-Rodgers Creek fault system carries the highest individual risk at roughly 34%, and the San Andreas Fault's odds climbed noticeably too, from 21.9% up to 25.5%. Zooming out statewide, the USGS's broader UCERF3 forecast still puts the 30-year odds of a magnitude 6.7+ quake at around 60% for the Los Angeles area, lower than the Bay Area's figure, though Southern California actually carries higher odds for the very largest ruptures (magnitude 7.5+).

An aerial view of a fault line's telltale ridge cutting across the landscape, the same kind of feature that traces the Hayward and San Andreas faults through the Bay Area.

Why the Odds Went Up

The increase isn't because seismologists found a new fault or new shaking potential out of nowhere. It's largely a function of time. USGS geophysicist Kevin Milner, who worked on the update, put it plainly: the Bay Area is in the middle of an unusually long earthquake drought compared to its historical pace, and the longer a fault goes without releasing built-up stress, the higher the probability that the stress gets released in the coming decades. As Milner put it, "We have to be prepared for a major earthquake. It is going to happen in most of our lifetimes."

What This Means If You Own Property Here

A shift from 72% to 74% might read like rounding error to some, but the practical takeaway for Bay Area property owners hasn't changed: a damaging earthquake within your lifetime is closer to a certainty than a possibility. Shaking is only part of the story. Liquefaction in fill and loose sandy soils, differential settlement, and slope instability during and after a quake routinely cause more structural damage to homes than the ground motion itself, especially on older foundations, hillside lots, and ADUs added onto an existing structure without a fresh geotechnical review.

What Actually Reduces Your Risk

Building codes have come a long way since 1868 and 1906, but code minimums are written for life safety, not full property protection. A site-specific geotechnical investigation before you build, add an ADU, or renovate tells you what your own soil will actually do in a major event: whether it's prone to liquefaction, whether your slope is stable, and what foundation design will hold up under real conditions. That's information a generic, decades-old soils report, or no report at all, simply can't give you.

If it's been a while since your property had a geotechnical evaluation, or you're planning new construction anywhere in the Bay Area or Sacramento Valley, now is a good time to get ahead of it. Reach out to AK Geotech to talk through what a site-specific investigation would look like for your property.

Sources: U.S. Geological Survey (September 2026 Bay Area earthquake probability update); USGS UCERF3 Long-Term Earthquake Forecast for California.