Automation error sends tremors through California
- By Matt Leonard
- Jun 23, 2017
A software issue is being blamed for accidentally sending out a U.S. Geological Survey alert for a 6.8 magnitude earthquake near Los Angeles.
Such an earthquake did occur -- in 1925.
The June 21 alert -- which was dated June 29, 2025 -- was sent after researchers at Caltech corrected location data in records of a past earthquake, according to reporting by the Los Angeles Times. A seismologist at the University of California at Santa Barbara had informed USGS' National Earthquake Information Center that its database contained inaccurate location information for the 1925 Santa Barbara earthquake. Researchers at Caltech were then asked to update the location in the Advanced National Seismic System database, according to the Times.
Washington State Seismologist John Vidale, who directs the Pacific Northwest Seismic Network, told GCN that people around the world sign up to get earthquake alerts from the USGS through the Earthquake Notification Service. Users can customize their alerts by deciding when they want to receive them, what magnitude of earthquake is needed to trigger a notification, etc.
“We all saw a magnitude 6.8 off Santa Barbara as being reported,” Vidale said about the alert. They passed the information along, but were able to determine in a matter of minutes that it was not accurate, he said.
Caltech Seismologist Egill Hauksson told the Times that the change in location was entered correctly, but because the notification scripts relied on Unix time, “1925 wrapped around in the software and became 2025.” The system interpreted that as a new event, and out went the notification.
Neither USGS nor Caltech responded to requests for comment.
Vidale said this isn’t the first time that alerts have been accidentally sent out. An alert was sent out for a magnitude 8 earthquake in southern California when officials running a training exercise forgot to adjust their system to training settings; a center in Hawaii did something similar for a quake in the Pacific, he said.
“This one, I think, caught more attention than most, partly because we are starting to implement systems that act automatically,” he said.
USGS quickly posted to Twitter that an error had occurred, and soon after sent out a correction via the Earthquake Notification Service. But the Times, which has its own automated software running, had already published a website article and a tweet about the quake, further spreading the false news.
“As we’re getting into an era of responding automatically, people are going to notice these things, and [officials] are going to have to work harder to make sure they don’t happen very often,” Vidale said.
Matt Leonard is a former reporter for GCN.