A look into ShakeAlert warning system after 6.0 NorCal quake notification rattles Bay Area residents

ABC7 News spoke with USGS to better understand how the ShakeAlert system works after a 6.0 earthquake prediction did not happen.
SAN JOSE, Calif. (KGO) -- Some Bay Area residents received a notification on their smartphones Thursday night about an earthquake that was potentially seconds away from hitting. The prediction, delivered via the USGS ShakeAlert system, was a magnitude 6.0 possibly centered in Placer County.

But after all was said and done, most of us didn't feel a thing. So, what exactly happened? ABC7 News spoke with the U.S. Geological Survey to better understand how the system works.

RELATED: 4.7 magnitude earthquake strikes near Truckee
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A 4.7 magnitude earthquake struck near Truckee Thursday night.



"One of the critical pieces of information with any earthquake is to know where it's located," said Robert de Groot, USGS ShakeAlert national coordinator. "When you know about where the earthquake is located, then you can get a sense of how the region around it is going to shake."

In this case, the system, which uses underground sensors to detect an earthquake, actually misread where the quake was located because there was only one station in the area. As a result, the quake ended up being closer to Truckee and turned out to only be a 4.7 on the scale. Some Bay Area residents were notified to take cover because the system thought the quake would be bigger.

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Despite the miscalculation, earthquake geologists say it's a good thing the system worked, and that the data will get even better as more sensors are installed throughout the state over the next four years.

"Those 10 or 20 seconds may save lives," said Kimberly Blisniuk, an earthquake expert and geology professor at San Jose State University. "What I think is great about this is that even though some people think that the system didn't work, it actually really did."

RELATED: How the Oakland ShakeAlert works

There are two mobile apps that are powered by ShakeAlert. One of them is the MyShake app that was developed by U-C Berkeley and is sponsored by Cal OES. The other is QuakeAlertUSA. ShakeAlert also provides warnings to Google, which has an earthquake alert feature on devices using the Android operating system. Another way to receive warnings is if you have wireless emergency alerts enabled on your smartphone device.

RELATED: California's Shake Alert earthquake warning system tested in Oakland

"I want people to think of it as a tool in their toolbox of earthquake preparedness," said de Groot.

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