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California Earthquake Early Warning System Gets an Early Test

Some of the alerts were received in as few as four seconds in a test that went to some 40,000 people in downtown Oakland and asked respondents a series of questions about receiving alert notifications.

California’s earthquake early warning system may have taken a step forward this week when officials conducted a test in downtown Oakland.

The USGS, in partnership with the California Governor’s Office of Emergency Services (Cal OES), the city of Oakland and Alameda County, issued Wireless Emergency Alerts (WEA) soliciting a response to a survey to about 40,000 people in a 60-acre block. It went well, but not perfectly.

About 970 who received the alert responded. The alert said it was a test of the California earthquake warning system and that no action had to be taken other than responding to a survey. The survey inquired about what time they received the alert; what kind of cellphone they had and the provider; and how they would like to receive alerts in the future.

 “Some of the devices displayed the message about four seconds after,” said Robert-Michael de Groot of the U.S. Geological Survey, and one of the coordinators of the ShakeAlert system. “It was a great first test to see where the latencies are. We want to work with FEMA and the cellphone industry to improve the delivery times because this is where a lot of the challenges remain on the delivery side of things.”

A real message in the future might include more instruction, such as drop, cover and hold on. Officials are working with social scientists about the best ways to craft messages that contain actionable information. The most important question for officials issuing the alert was the time respondents received the notification. Overall, officials were pleased with the results, which they were continuing to examine.

“There was an industry report that came out in 2015 that said transmission time would take at least 30 seconds, but we were hearing from some carriers that since they’ve been upgrading to 4G LTE as well as new handsets that it could be a lot faster,” said Ryan Arba, branch chief for seismic hazards at Cal OES.

A lot of the respondents indicated a desire to receive the WEA alerts rather than sign up for an app and that was welcome news. “It represents most of the public alerts,” de Groot said. “WEA is going to be a major piece of the puzzle for ShakeAlert, although the latency is still a concern.”

The WEA messages are delivered through cell broadcast, whereas the messages delivered from an app are via push notification. It wouldn’t hurt to have both. “The great thing about push notification and apps is that there’s much more value add,” de Groot said. “You can add additional content on the app about what to do after the alert.” The WEA messages are limited by characters.

“I see a role of apps and WEA as being very complimentary,” de Groot said. “It’s OK to get both. Actually, you may get one and not the other.”

During the test, USGS and OES officials had about 30 phones in a room in downtown Oakland to observe as they sent out the alert. They started going off in four seconds. Some took longer and some handsets didn’t receive an alert at all.

“We have to balance the limitations of wireless emergency alerts, such as the limits on characters, and the fact that it’s not a silver bullet,” Arba said. “Based on our preliminary results, we know that some people won’t get the alert, it doesn’t go to every handset and we don’t know why but we want to collect that data and work with carriers to make it better and try to make it so that there’s a way to make sure all phones get it in a few seconds. We have a lot of work to do.”