Major modern quakes of Puget Sound

Since 1900, six earthquakes of magnitude 5.0 or greater have been recorded as having caused damage in Snohomish and Island counties, or were centered within the counties’ borders.

Where the faults lie

Two significant faults run through Snohomish and Island counties. The South Whidbey Island Fault Zone consists of several intermittent faults that run from the Strait of Juan de Fuca southeast across Whidbey Island and south Snohomish County to Woodinville. The Devils Mountain Fault runs from the Strait of Juan de Fuca east near Deception Pass and across the Skagit-Snohomish county line southeast to Darrington.

Geologic evidence shows that large quakes have happened in the South Whidbey and Devils Mountain fault zones in the distant past. One happened in 1950 in the South Whidbey fault zone but data is inconclusive about the fault of origin, said Bill Steele, coordinator of the University of Washington Seismology Lab.

Quakes on these faults carry a potential magnitude of 7.5, which could cause severe damage because of their proximity to the surface, according to a natural hazard report done for Snohomish County in 2010. A quake in the Cascadia Subduction Zone 50 miles off the Pacific coast could inflict a quake of up to 9.5 in magnitude, causing catastrophic damage and capable of starting a tsunami, according to the report.

Major modern-era Puget Sound quakes

View Major modern-era Puget Sound earthquakes in a larger map

Fault locations are approximate.

SOURCES: University of Washington Seismology Lab, U.S. Geological Survey, state Division of Geology and Earth Resources

More online

Snohomish County Natural Hazard Mitigation Plan update [PDF]

Pacific Northwest Seismic Network

U.S. Geological Survey

Washington Division of Geology and Earth Resources

Talk to us

> Give us your news tips.

> Send us a letter to the editor.

> More Herald contact information.

More in Local News

A Cessna 150 crashed north of Paine Field on Friday evening, Feb. 16, 2024, in Mukilteo, Washington. The pilot survived without serious injury. (Courtesy of Richard Newman.)
‘I’m stuck in the trees’: 911 call recounts plane crash near Paine Field

Asad Ali was coming in for a landing in a Cessna 150 when he crashed into woods south of Mukilteo. Then he called 911 — for 48 minutes.

Everett
Snohomish County likely to feel more like winter, beginning Monday

Get ready for a mix of rain and snow this week, along with cooler temperatures.

Anthony Boggess
Arlington man sentenced for killing roommate who offered shelter

Anthony Boggess, 33, reported hearing the voices of “demons” the night he strangled James Thrower, 65.

Patrick Kunz speaks during his sentencing on Thursday, Feb. 29, 2024, at Snohomish County Superior Court in Everett, Washington.(Annie Barker / The Herald)
Everett gymnastics coach who spied on students sentenced to 6 months

Patrick Kunz, 47, pleaded guilty to charges of voyuerism and possession of child pornography last month.

Traffic moves along Highway 526 in front of Boeing’s Everett Production Facility on Nov. 28, 2022, in Everett, Washington. (Olivia Vanni / Sound Publishing)
Everett transgender mechanic alleges Boeing treated her ‘like a zoo animal’

For years, Boeing allowed toxicity “to fester and grow” at its Everett factory, according to Rachel Rasmussen, an employee from 1989 to 2024.

Monroe High School (Monroe School District)
Monroe High School teacher accused of sexual misconduct, put on leave

Few details were not available Thursday afternoon. Police were seeking information from the public.

Everett
After 10 months, police make arrest in fatal Everett shooting

Police believe Malik “Capone” Fulson killed Joseph Haderlie, 27, in April 2023 outside an apartment complex on Casino Road.

Kathy Purviance-Snow poses for a photo in her computer lab at Snohomish High School on Tuesday, Feb. 27, 2024, in Snohomish, WA. (Annie Barker / The Herald)
To ban or embrace ChatGPT? Local teachers fight AI with AI — or don’t

“It has fundamentally changed my teaching in really stressful and exciting ways,” an EvCC teacher said. At all levels of education, ChatGPT poses a tricky question.

Ryan Rafter appears in court for sentencing Wednesday, Feb. 28, 2024, at Snohomish County Superior Court in Everett, Washington. (Ryan Berry / The Herald)
Man sentenced to life in prison for murder of Everett father

In April 2022, Ryan Rafter, 42, shot Christopher Buck, 29, to death after breaking in to his home to steal drugs.

Marysville
Driver strikes, kills Marysville man who was crossing I-5 in Seattle

The man’s car had broken down near Mercer Street. Troopers reported that he was struck when he tried to cross the freeway.

Logo for news use featuring the municipality of Darrington in Snohomish County, Washington. 220118
Police: Darrington woman stabbed, buried 5-year-old daughter

The woman reportedly told investigators she was hearing voices before she killed her young daughter on Valentine’s Day.

In this Feb. 5, 2018, file photo a Boeing 737 MAX 7 is displayed during a debut for employees and media of the new jet in Renton, Wash. (AP Photo/Elaine Thompson, File)
FAA gives Boeing 90 days to develop plan to fix quality, safety issues

The agency’s ultimatum comes a day after a meeting with CEO Dave Calhoun and other top Boeing officials in Washington, D.C.

Support local journalism

If you value local news, make a gift now to support the trusted journalism you get in The Daily Herald. Donations processed in this system are not tax deductible.