The Herald of Everett, Washington
HeraldNet on Facebook HeraldNet on Twitter HeraldNet RSS feeds HeraldNet Pinterest HeraldNet Google Plus HeraldNet Youtube
HeraldNet Newsletters  Newsletters: Sign up | Manage  Green editions icon Green editions
Herald staff | needtoknow@heraldnet.com
Published: Sunday, July 22, 2012, 12:01 a.m.

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
Story tags » EarthquakeNatural Sciences

Sign up for HeraldNet headlines Newsletter
See sample | Privacy policy

Most recent Need to Know posts

Share your comments: Log in using your HeraldNet account or your Facebook, Twitter or Disqus profile. Comments that violate the rules are subject to removal. Please see our terms of use. Please note that you must verify your email address for your comments to appear.

You are logged in using your HeraldNet ID. Click here to update your profile. | Log out.

Our new comment system is not supported in IE 7. Please upgrade your browser here.

comments powered by Disqus
digital subscription promo

Subscribe now

Unlimited digital access starting at 99 cents, or included with any print subscription.



HeraldNet highlights

Looking for a friend?
Looking for a friend?: Animals up for adoption at the Everett shelter (new photos)
Quietly radical 'Boyhood'
Quietly radical 'Boyhood': Unique film explores awkward years with grace
Scarlett gets serious
Scarlett gets serious: Johansson finds her stride in 'Lucy'
'What's next?'
'What's next?': 7 questions for the offense as Seahawks hit training camp