LOS ANGELES (CNS) - The ShakeAlertLA app that drew criticism when it didn't notify users about the powerful July 4 and 5 earthquakes near Ridgecrest, even though they rattled the Southland, will begin sending alerts for smaller quakes, officials announced today.
Starting this month, the early warning system began alerting residents of earthquakes at magnitude 4.5 or larger, according to Los Angeles Mayor Eric Garcetti, Caltech and the U.S. Geological Survey. The previous threshold was magnitude 5.0.
Officials stressed that the ShakeAlertLA app actually worked as designed during the magnitude 6.4 and 7.1 quakes near Ridgecrest, because the shaking that occurred in the Los Angeles area was below the 5.0 threshold for a notification. Designers of the app said they wanted it to be reserved for only the strongest quakes.
“We wanted to balance the need to let people know of earthquakes and also to make sure that we didn't cause too much chaos, that people weren't running out of crowded theaters or driving off the sides of the road just because they knew an earthquake was coming,” Garcetti said.
But given the widespread shaking that occurred, many residents complained about the lack of any warning from the app. So officials said Wednesday they have agreed to lower the threshold for notifications.
“What this means is simple -- Angelenos will get more alerts about earthquakes,” Garcetti said.
The ShakeAlert system, through monitors placed across the West Coast, is designed to give people advance warning of pending shaking, even if that warning is only a matter of minutes. Officials say even a short warning can give people enough time to seek shelter, or hospitals enough notice to halt surgeries.
When people receive a ShakeAlert notification, they are advised to take protective action, such as drop, cover and hold on.
While officials agreed to lower the notification threshold on the app, they warned about the danger of people receiving too many alerts.
“Our fear is that they will become desensitized to the alerts and not act to protect themselves in those instances when they really need to,” said Doug Given, the USGS' earthquake early warning coordinator.
ShakeAlertLA was developed in collaboration with USGS, AT&T and The Annenberg Foundation. It was introduced at the end of last year.
More information can be found at www.shakealert.org.