# Global and North American seismic risk assessment

> Live situation record from CLSTR: https://clstr.news/situations/global-and-north-american-seismic-risk-assessment
> Updated: 2026-09-05T10:00:49.000Z. Sources: 18. Developments: 3.

Global seismic activity has prompted renewed scientific focus on the potential for devastating megathrust earthquakes. In North America, significant tension has been identified in the San Andreas Fault system, with tectonic loads reaching levels not seen in approximately 1,000 years. Concerns also extend to the Cascadia Subduction Zone, which stretches from northern California to Vancouver Island.

The third Uniform California Earthquake Rupture Forecast indicates an increased probability of major events. The chance of a magnitude 6.7 or stronger earthquake hitting the Bay Area within the next 30 years has risen to 74.1%, a 2.1% increase from a decade ago. Additionally, the San Andreas Fault's 30-year rupture probability has increased to 25.5%, while the Hayward-Rodgers Creek fault system carries a 34.3% probability. Scientists noted that a linked rupture between these two systems could potentially generate a magnitude 7.4 earthquake.

Researchers have identified the Cajon Pass as a critical area of concern, describing it as a potential ‘earthquake gate’ that could influence the propagation of large ruptures. Along the West Coast, experts emphasize that a major earthquake, often referred to as ‘the big one’, is an inevitability. Research by experts, including Yumei Wang of Portland State University, highlights critical vulnerabilities in infrastructure, such as school building safety and the reliability of 911 emergency services, which could impede recovery efforts and increase casualties.

## Timeline

### 2026-09-05: US West Coast faces high risk from overdue major earthquakes

Experts warn that the US West Coast is overdue for a catastrophic earthquake from the San Andreas or Cascadia faults, highlighting critical infrastructure vulnerabilities and the need for better preparedness.

3 sources. https://clstr.news/cluster/us-west-coast-faces-high-risk-from-overdue-major-earthquakes

### 2026-09-02: California earthquake risk increases in new seismic forecast

New USGS forecasts show the probability of a magnitude 6.7 or greater earthquake hitting the California Bay Area has risen to 74.1% over the next 30 years due to accumulating tectonic stress.

6 sources. https://clstr.news/cluster/california-earthquake-risk-increases-in-new-seismic-forecast

### 2026-08-23: Global seismic activity raises concerns over potential megathrust earthquakes

Increased global seismic activity has heightened concerns regarding the “Big One,” specifically focusing on high-risk zones like the San Andreas Fault and the Cascadia Subduction Zone.

9 sources. https://clstr.news/cluster/social-dynamics-and-neighborly-coexistence-face-shifts-in-residential-communities

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Cite as: Global and North American seismic risk assessment. CLSTR, https://clstr.news/situations/global-and-north-american-seismic-risk-assessment