Aftershocks follow 4.2-magnitude earthquake near Gig Harbor, WA
Aftershocks follow 4.2 earthquake near Gig Harbor
Roughly 10,000 Washingtonians reported feeling a 4.2 magnitude earthquake that struck near Gig Harbor two weeks ago. But at least four aftershocks followed, though they were too small to feel.
SEATTLE - A magnitude 4.2 earthquake in Gig Harbor prompted roughly 10,000 Washingtonians to report feeling the shaking. In the days that followed, at least four aftershocks were too small to feel, according to Harold Tobin, director of the Pacific Northwest Seismic Network.
Now, about two weeks after the earthquake, seismologists are reviewing what it revealed about the region’s faults as Washington prepares for its annual Great ShakeOut drill.
"Every earthquake like this, lights up in a sense for us a little spot in the earth’s crust that tells us just a little bit more about the patterns of earthquakes and the faults in our region," said Tobin.
What seismologists learned
The backstory:
The Gig Harbor earthquake was Washington’s largest so far this year and the largest in the state since an earthquake near Orcas Island in 2025, said Tobin.
Once the network detected the shaking, seismologists immediately began reviewing the data, checking the epicenter and publishing the earthquake’s location and magnitude within a couple of minutes, he said.
One early question was whether the earthquake originated along the Tacoma Fault.
Although the shaking occurred near that fault, the earthquake began18 miles underground, beneath it, said Tobin. That puts its origin in an area where the seismic picture is less clear to researchers.
What they're saying:
Tobin and seismologists at the University of Washington have continued reviewing their findings. At least four aftershocks followed over the next few days, all too small for people to feel, he said.
The smaller tremors are part of a much larger number of earthquakes recorded across the region.
"We’ve had thousands of earthquakes we’ve recorded just in 2026 alone," remarked Tobin. "The vast majority of them are too small for people to feel. 4.2 is definitely a wakeup call."
(Pacific Northwest Seismic Network)
Why a phone alert did not go out
Dig deeper:
The earthquake was below the magnitude threshold for a general cellphone broadcast warning, according to Tobin.
"It turns out that for everyone to get an alert through the amber alert style broadcast to your phone it would have to be magnitude 5," he explained.
The magnitude 4.2 earthquake did not meet that threshold.
A chance to practice before the next earthquake
What you can do:
Washington’s Great ShakeOut drill is scheduled for 10:15 a.m. Thursday, Oct. 15, with about 1.4 million people in the state registered to participate.
Tobin described the drill as a chance to practice responding to an earthquake, much like a fire drill. The recent shaking should also serve as a reminder to check emergency kits and think through what to do when an earthquake strikes, said Tobin.
His advice: Drop, cover and hold on. Get beneath something sturdy if possible, protect your head and neck, and do not run outside.
MORE NEWS FROM FOX 13 SEATTLE
Problems growing with ‘Larch Madness’ in WA's North Cascades
1 dead, 1 injured after drive-by shooting at South Seattle nightclub
Tiger that killed man at wildlife park will not be euthanized, officials say
Longtime Seattle restaurant Pam's Caribbean Kitchen closing Nov. 29
12 killed, over 300 hurt in attack at Saudi airport, officials say
Trump says Russia, Ukraine agree to immediate ‘energy ceasefire’ amid tensions with Zelenskyy
Seattle Kraken surge late to top Capitals in 5-3 victory
To get the best local news, weather and sports in Seattle for free, sign up for the daily FOX Seattle Newsletter.
Download the free FOX LOCAL app for mobile in the Apple App Store or Google Play Store for live Seattle news, top stories, weather updates and more local and national news.
The Source: Information in this story comes from original reporting by FOX 13 Seattle reporter Lauren Donovan.