Experts evaluate earthquake potential off Washington coast

cascadiasubductionzone_earthquake.jpg
The Northwest's largest earthquake zone, just off the coast, which is called the Cascadia Subduction Zone (highlighted above) mirrors the area where the quake rocked Japan last March. (Image courtesy Pacific Northwest Seismic Network) | Zoom
In the eleven months since the massive quake and tsunami hit Japan, the world's leading earthquake scientists learned that a mega quake in the Northwest could be a lot worse than experts have predicted.

The Northwest's largest earthquake zone, just off the coast, which is called the Cascadia Subduction Zone mirrors the area where the quake rocked Japan last March.

From the data recorded there, the Seattle Times reports that experts now believe a mega-quake in the Northwest could be more severe.

They are now working to create a new analysis of the hazards off the coasts of Washington, Oregon and British Columbia.

One new theory is that the topography of the sea floor is the key. Flat and featureless bottoms, like the bottom off Washington's coast, seem to experience mega quakes more often.

Fortunately, last week, a large earthquake off the coast of Oregon didn't have the devastating impact of a mega-quake concerning researchers.

The National Earthquake Information Center in Golden, Colo., says a magnitude 6.0 quake off the Oregon coast caused no reported damage and only a smattering of reports from people who felt it as a weak jolt.

The shallow quake recorded at 7:31 p.m. on Feb. 14 more than 150 miles west of southern Oregon did not generate a tsunami.

Within about an hour, the information center's website recorded 39 reports of people who reported feeling the quake. Most were in northern California and southern Oregon and characterized it was "weak" or "barely felt."

U.S. Geological Survey geophysicist Dale Grant said in a telephone interview the quake occurred in a seismically active area and called it "not uncommon at all."

In his words, "These are the ones we like - nobody gets hurt and there's no damage."

According the Pacific Northwest Seismic Network, the last known great earthquake in the northwest was in January, 1700, just over 300 years ago.

The Associated Press and 97.3 KIRO FM's Chris Sullivan contributed to this report.

MyNorthwest.com, Staff report
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Comments (6)


  • Add A Comment

  • mkrcr wrote...
    I'm Thinkin'
    300 years since the last major quake? Tick, Tock, Tick, Tock. When it happens we'll see how great that tunnel is then.
    { "Thumbs Up":"1","Thumbs Down":"-1" }
  • CH wrote...
    * Experts[LOL] evaluate earthquake potential off Washington coast . . . .
    snow this weekend! Seatbelt on let-er-rip.
    { "Thumbs Up":"1","Thumbs Down":"-1" }
  • regular joe 2u wrote...
    Go a head and LOL all you want
    But if we have a Mega quake and a tsunami I can bet my last buck you won't be doing much LOL then. I am glad to see some valuble research brought out from the Japan's Mega quake and tsunami. Way to go USGS I love your sites and visit your site 3-4 daily
    { "Thumbs Up":"1","Thumbs Down":"-1" }
  • Mo Gaud wrote...
    And don't forget
    volcanoes, floods, windstorms, forest fires, and the dreaded lahar. Of course nothing at all might happen, but that doesn't make for very dramatic news stories, does it?
    { "Thumbs Up":"1","Thumbs Down":"-1" }
  • Ron_Spins wrote...
    Worse than a 9.0 vertical uplift quake?
    Look for total devastation and no Starbucks open for three months.
    { "Thumbs Up":"1","Thumbs Down":"-1" }
  • Newton wrote...
    Oh that tunnel will be a death trap all right.
    Won't catch me in it. Notice the Convention center over I-5 that was smart.
    { "Thumbs Up":"1","Thumbs Down":"-1" }
  • { "Thumbs Up":"1","Thumbs Down":"-1" }