Why you didn’t get an alert about Sunday evening’s earthquake

For those users who signed up for alerts in the past wondering why one didn’t pop up on their phones after Sunday evening’s earthquake, that’s simply because it wasn’t a big enough seismic event.

The magnitude 4.3 earthquake fell under the threshold needed to trigger automated alerts. The epicenter was located under Marrowstone Island near Port Townsend and about 10 miles from Freeland in Island County. Residents from Olympia to Vancouver, British Columbia, told the U.S. Geological Survey (USGS) they felt the ground move.

“For some of the apps, like MyShake, which you can download on your phone, that’s still set at a magnitude 4.5 threshold and this didn’t quite meet those thresholds,” Harold Tobin of the  Pacific Northwest Seismic Network told KIRO Newsradio.

More from MyNorthwest: Check out our earthquake tracker

MyShake delivers the USGS’ ShakeAlert across Washington, Oregon and California. It is operated out of the Berkeley Seismological Laboratory at the University of California Berkeley and run in partnership with the USGS and California Governor’s Office of Emergency Services (Cal OES).

The seismic network wrote on X, formerly known as Twitter, Sunday night ShakeAlert did detect the earthquake and charted warning times as if it had sent an alert. It reported Port Angeles and Seattle would have had “up to about 11 seconds warning time before the strong shaking arrived.” Even Port Townsend, nearly at the earthquake’s epicenter, could have had about five seconds notice, the organization added. That was because of the earthquake’s depth.

Folks may be wondering why they did not get an earthquake warning message on their phones. ShakeAlert & WEA did not send out a public warning because the quake was not big enough to meet the alert threshold. It did detect it, and these are the potential warning times: (1/2) pic.twitter.com/J3Z1PxK3BZ

— PNSN (@PNSN1) October 9, 2023

Experts warn that while Sunday’s earthquake didn’t bring with it a huge number, or any reports of major damage, it wouldn’t have to be bigger than a magnitude of 5.5 to damage some buildings.

One of those past earthquakes that did cause damage — the 2001 Nisqually magnitude 6.8 earthquake that injured hundreds of people and caused millions of dollars in damage — hit around the same depth into the earth.

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The public is urged to keep an emergency kit in their homes or cars just in case.

“People just need to treat this as a little bit of a reminder or a wakeup call that earthquakes happen in our region. We know that for sure. We’ve seen that in the past,” Tobin told KIRO Newsradio.

Steve Coogan is the lead editor of MyNorthwest. Sam Campbell is a reporter for KIRO Newsradio.