Washington, D.C. – Five members of California’s Congressional delegation, including the top Democrats on the relevant House committees, sent a letter to the U.S. Geological Survey (USGS) seeking information about its ShakeAlert earthquake early warning system and what may have led to last week’s false alarm.

On Dec. 4, 2025, a false alert went out for a magnitude 5.9 earthquake that never occurred near the California-Nevada border, which triggered notifications to residents hundreds of miles away including in the San Francisco Bay Area.

Rep. Kevin Mullin (CA-15), Science, Space, and Technology Committee Ranking Member Zoe Lofgren (CA-18), Natural Resources Committee Ranking Member Jared Huffman (CA-02), and Reps. Eric Swalwell (CA- 14), and Laura Friedman (CA-30), have asked the USGS about what protections are in place to prevent future false alarms and ensure the integrity of the early warning system.

“Seconds matter during an emergency, and alert systems can save lives when used properly. Our technology has come a long way in helping to warn people when they need to brace for an earthquake,” said Rep. Mullin. “Alert fatigue and false alarms are a real issue, especially since we need to be building more public trust in our emergency alert systems. We need to ensure the federal government is properly funding and supporting these crucial public safety systems so that they are reliable and trustworthy.”

The lawmakers are asking the USGS to provide more information on:

• Why multiple seismic stations reported false shaking on Dec. 4
• What safeguards exist to validate seismic readings before issuing public alerts
• How the USGS is working with state and local officials to assess the impacts of false alerts and identify improvements
• What criteria determine whether and when alerts are sent to the public

Read a full copy of the letter here.

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