California Earthquake Early Warning System Benefit-Cost Analysis

California’s Early Earthquake Warning alerts can help reduce derailment risk for mass transit. Photo: Wikimedia

Supporting benefit-cost analysis to guide California’s earthquake early warning adoption and priorities

The California Governor’s Office of Emergency Services (Cal OES) oversees statewide emergency preparedness, including the Early Earthquake Warning (EEW) system. Using U.S. Geological Survey ShakeAlert® data, the system sends alerts seconds before shaking reaches people, infrastructure, and public services. 

In 2023, Cal OES commissioned UC Berkeley’s Pacific Earthquake Engineering Research Center (PEER) to conduct a benefit-cost analysis of California’s EEW program to update prior analyses, evaluate current EEW use, and identify ways to improve and expand the system. Greene Economics joined a multidisciplinary team to support the research.

The team conducted a literature review and stakeholder interviews, including research on user perception and behavior change. We developed detailed benefit-cost estimates for four priority EEW use cases—smartphone alerts, school PA systems, mass transit, and elevator car controls—and built a scenario tool to model alternative investment and alert-response strategies. Working closely with the team's primary economist, we determined, collected and managed data to calculate the estimated costs and benefits of each scenario, consistent with the Third Uniform California Earthquake Rupture Forecast (UCERF3), California’s statewide earthquake forecast.

The study found that California’s EEW system delivers measurable benefits across public safety, infrastructure, and business sectors, including reduced injuries, fewer elevator entrapments, and lower derailment risk. Opportunities include targeting high-risk users (construction workers, truck drivers, utility crews, and nurses) to improve responses to alerts, expanding automated alerts, and strengthening the vendor ecosystem to scale EEW statewide.

The report and scenario tool will help Cal OES prioritize investments, improve alert responses, and strengthen EEW use statewide to protect communities.