Overview
- The Bay Area is taking stock on the 120th anniversary of the 1906 magnitude 7.9 earthquake, which killed about 3,000 people, as USGS still pegs a 72% chance of a magnitude 6.7 or stronger quake in the next three decades.
- A 2025 study in Geosphere stitched together offshore and lake sediments to chart 19 major northern San Andreas events over roughly 3,100 years, suggesting an average repeat time near 210 to 220 years.
- The study reports that 10 of those San Andreas quakes occurred around the same time as Cascadia Subduction Zone events, with some layers hinting they were minutes to hours apart, though other scientists say dating gaps make firm links uncertain.
- San Francisco faces concentrated risk in more than 3,700 pre-1995 concrete buildings identified by SPUR, and the city now requires owners of at-risk structures to self-report to staff by June 2027.
- Officials are updating the city’s earthquake plan by the end of 2026 and asking voters in June 2026 to approve a $535 million bond for upgrades to fire and police stations, the 911 center, an emergency water system, and transit, while early alerts like MyShake still offer little warning near a major epicenter.