Earthquake jolts Western Washington on Christmas Eve

The U.S. Geological Survey (USGS) confirmed a 4.0-magnitude earthquake hit Western Washington at 7:14 a.m. on Sunday, Christmas Eve.

The epicenter was located about four miles from Quilcene, the agency reported. The agency also noted Bremerton (23 miles away) and Victoria, British Columbia (46.4 miles), as “nearby places” to the tremor.

More information: Check out the MyNorthwest Earthquake Tracker

As of 11 a.m. Sunday morning, people felt the earthquake as far south as Olympia and as far north as Vancouver, British Columbia, according to more than 650 user responses to the USGS’ intensity map. Reports also have come in from across the Puget Sound region, including in Seattle, Tacoma, Kent, Everett and Oak Harbor.

The earthquake also had a depth of over 32 miles (about 52 kilometers), according to the USGS and the Pacific Northwest Seismic Network (PNSN).

As of 11 a.m. Sunday, the tremor had not spurred any messages or posts on X, formerly known as Twitter, from the National Oceanic and Atmospheric Administration’s U.S. Tsunami Warning System.

“It woke me and my family up,” Snohomish County resident and Bonneville Seattle employee Michael Simeona said Sunday morning.

NEW: Mag:4.1 25.2 km WNW from Poulsbo, WA Depth:51km 2023/12/24 07:14 PST Version:4
More info: https://t.co/CEFEXSr2tG
Did You Feel It? report here: https://t.co/cBl9Czs2Qf pic.twitter.com/pU3sDVM4sP

— PNSN (@PNSN1) December 24, 2023

Second Washington earthquake over 4.0 in 2023

A 4.3-magnitude earthquake struck the Puget Sound region on the evening of Oct. 8.

Seismic activity: 4.3-magnitude earthquake felt across Puget Sound region

The epicenter was located just under Marrowstone Island near Port Townsend and approximately 10 miles from Freeland in Island County. The PNSN reported the epicenter was 20 miles from Poulsbo about 23.5 miles away from Everett.

“I felt it here in downtown Seattle, sofa shaking and the water inside a bottle also moving a little bit,” one resident told KIRO 7 at the time.

Before the two earthquakes late this year, the last time Washington state had a 4.0 magnitude earthquake was in 2019 when a 4.6 earthquake hit near Monroe, The Seattle Times noted in its coverage.

According to an article published on the University of Washington’s website earlier this year, “Seattle has two primary faults: The Seattle Fault that runs east-west through the middle of the city, capable of earthquakes up to 7.4 magnitude, and the Cascadia Subduction Zone along the coast, capable of a magnitude 9 earthquake.”

The PNSN explains that the Seattle Fault — a crustal fault — runs through Seattle, under Lumen Field, west across Bainbridge Island to Hood Canal and east out past Issaquah roughly following Interstate 90.  This fault produced a large earthquake that left a geologic record of surface offsets about 1,100 years ago.

The Cascadia Subduction Zone — a “megathrust” fault — is a 620-mile long dipping fault that stretches from Northern Vancouver Island to California’s Cape Mendocino, the PNSN notes. The last known megathrust earthquake in the northwest was over 320 years ago in January 1700.

Why you didn’t get an alert about the earthquake

For those users who signed up for alerts in the past wondering why one didn’t pop up on their phones after Sunday’s earthquake, that’s because it wasn’t a big enough seismic event. The magnitude 4.0 earthquake fell under the threshold needed to trigger automated alerts.

“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 after the magnitude 4.3 earthquake hit the region in October.

Alerts and suggestions: Public is urged to keep at least 1 emergency kit

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).

Contributing: Frank Sumrall, MyNorthwest; Sam Campbell, KIRO Newsradio