False Earthquake Alert Likely Triggered by ‘Something Out in the Field,’ USGS Says

The errant earthquake warning that lit up phones across Northern California with a notice of a quake in Nevada on Thursday morning was not a result of a problem with the early warning delivery system or MyShake phone application, officials said.

At least four separate seismic stations detected ground motion “that told the system there was an earthquake,” which triggered the false warning of a magnitude 5.9 earthquake, according to officials with the U.S. Geological Survey.

The USGS quickly canceled the warning and posted a statement online that said there was no earthquake at all.

“This is the very first time we’ve had what I call a through and through false alert delivery because of something that may have happened out somewhere out in the field,” ShakeAlert operations team lead Robert de Groot told KQED. “We’ve had occurrences where we’ve alerted more people than should have been alerted, but [in this case] something triggered the system, but it wasn’t an earthquake.”

USGS officials do not yet know what caused the shaking. De Groot said research teams are analyzing information from other seismic stations and could potentially launch a field investigation.

“Earth does different things all the time and we can’t know everything, but we’re continuing to improve the system to understand,” he said.

The alert, which urged people to “drop, cover and hold on” to prepare for imminent shaking, caused at least one TV station, KTVU, to report on the quake.

Four million Californians have downloaded the MyShake app, which provides real-time alerts for earthquakes on smartphones.

The app was developed at UC Berkeley’s Seismology Lab and funded by the California Governor’s Office of Emergency Services (Cal OES). It buzzes when an earthquake of a magnitude of 4.5 or higher occurs.

Berkeley’s seismology team posted a statement to social media at 9:55 a.m. about the false alert by the USGS ShakeAlert system and distrubuted by the MyShake phone application.

“This system has delivered more than 170 real alerts since 2019 and this incident is both unprecedented and rare,” MyShake said on X. “Fortunately, there was no danger this morning, but this serves as a reminder that earthquake preparedness is essential.”