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Slow Seismic Slip Event Underway in Pacific Northwest
www.livescience.com ^ | Updated 2:35 p.m. ET Sept. 14 -13 September 2005 | By Robert Roy Britt

Posted on 09/14/2005 3:20:11 PM PDT by Esther Ruth

Slow Seismic Slip Event Underway in Pacific Northwest By Robert Roy Britt LiveScience Managing Editor posted: 13 September 2005 10:03 pm ET

Updated 2:35 p.m. ET Sept. 14

An important seismic event imperceptible to humans has begun in the Pacific Northwest as predicted, according to the government agency Geological Survey of Canada.

The chance of a major earthquake is 30 times higher now for a roughly two-week period, but the odds are still remote, scientists say.

The event is called episodic tremor and slip (ETS). It involves a slow movement of the Juan de Fuca and North America tectonic plates along the Cascadia margin of southern British Columbia. Faults associated with the plates have been the sites of major earthquakes -- akin to the colossal tsumani-causing quake last December in Indonesia -- every 500 years or so, the geologic record shows. The last such temblor in the area struck on Jan. 26 in the year 1700.

Slow creep

The movement is slower than a traditional earthquake but more rapid than the normal creep associated with the fault. It runs in the reverse direction of the normal creep.

(Excerpt) Read more at livescience.com ...


TOPICS: News/Current Events
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The movement was predicted. Scientists recently learned that these ETS events recur about every 14 months. It has been detected by Global Positioning System instruments.

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Deadly Earthquakes

The event does not mean an earthquake is imminent, but geologists are eager to study it and learn more and they say sooner or later an ETS event is likely to trigger a major quake.

"Compared to the steady year-round stress accumulation, this more rapid stress increase implies that a large subduction earthquake is more likely to happen during the time of an ETS event," the Canadian geologists write.

The slippage and associated minor tremors "are directly related to megathrust (Sumatra-like) earthquake potential," lead geologist John Cassidy and a colleague said in Tuesday's statement. "Neither the tremor nor the slip can be felt."

Odds go up

The slip began Sept. 3 on the Olympic Peninsula of Washington State and has migrated north to the Vancouver Island area, Cassidy wrote. Victoria moved 0.12 inches (3 millimeters) to the West over the course of two days. The events are thought to last six to 15 days.

Cassidy's colleague, Stephane Mazzotti, has done some calculations on the odds of a large temblor.

"The probability of occurrence of a megathrust earthquake is about 30 times higher during this approximately two-week window, than during the rest of the 14.5 month cycle," Cassidy told LiveScience. "Having said that, 30 times a small number is still a small number."

Geologists simply don't know when one of these events will trigger a major quake, Cassidy said.

The immediate importance of the event is that it occurred as predicted and can now be used to improve understanding of the region's seismology.

"By better understanding these events, we will be able to better predict the effects (and perhaps timing) of future magnitude 9 earthquakes along the West Coast," Cassidy and his colleague write.

A separate study recently concluded that a major earthquake along the fault could be overdue, given clusters of the events seen in the geologic record. Because the fault is offshore, scientists say its rupture could create a devastating tsunami

1 posted on 09/14/2005 3:20:11 PM PDT by Esther Ruth
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To: Esther Ruth

hmmmm.


2 posted on 09/14/2005 3:20:45 PM PDT by Peach (South Carolina is praying for our Gulf coast citizens.)
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To: Esther Ruth

Drudge has this posted on his sight.


3 posted on 09/14/2005 3:20:52 PM PDT by Esther Ruth (I have loved thee with an EVERLASTING LOVE, Jeremiah 31:3 Genesis 12:1-3)
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To: Peach

If I remember correctly, the estimate of "every 500 years" is invalid. Averaging the estimated periods between the events doesn't mean anything when there is such a huge disparity between the longest known period between events and the shortest.


4 posted on 09/14/2005 3:26:39 PM PDT by coconutt2000 (NO MORE PEACE FOR OIL!!! DOWN WITH TYRANTS, TERRORISTS, AND TIMIDCRATS!!!! (3-T's For World Peace))
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To: Peach

http://earthquake.usgs.gov/recenteqsww/Quakes/quakes_all.html

I haven't watched this for awhile so don't know if the activity by Mt St Helen is up or just same as usual.


5 posted on 09/14/2005 3:30:05 PM PDT by Esther Ruth (I have loved thee with an EVERLASTING LOVE, Jeremiah 31:3 Genesis 12:1-3)
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To: coconutt2000

The value of 500 years was calculated by a moving temporal average of a poisson distribution written on a slip of paper and pulled out of a hat.


6 posted on 09/14/2005 3:31:47 PM PDT by SpaceBar
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To: Esther Ruth

More evidence of global worming...


7 posted on 09/14/2005 3:35:29 PM PDT by DoughtyOne (US socialist liberalism would be dead without the help of politicians who claim to be conservative.)
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To: Esther Ruth
It runs in the reverse direction of the normal creep.

That sounds ridiculous. How are you going to stop a trillion tons of rock and make it suddenly move backwards?

8 posted on 09/14/2005 3:39:15 PM PDT by Royal Wulff
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To: DoughtyOne
More evidence of global worming...

Oh, that's bad...

9 posted on 09/14/2005 3:46:01 PM PDT by wyattearp (The best weapon to have in a gunfight is a shotgun - preferably from ambush.)
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To: Esther Ruth
The chance of a major earthquake is 30 times higher now for a roughly two-week period

I'm not going to tell my wife about this...and if I time it just right, and the the earthquake does occur...[heh,heh]

10 posted on 09/14/2005 3:49:57 PM PDT by Snardius
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To: Esther Ruth

Another fault of Bush. He didn't sign the Koyote agreement!
Global warmint, Oz-one hole, Katerina, Tsunami, quakes....


11 posted on 09/14/2005 3:53:40 PM PDT by Leo Carpathian (FReeeePeee!)
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To: SpaceBar

More likely a PDOOMA.

Semper Fi,


12 posted on 09/14/2005 4:09:02 PM PDT by 2nd Bn, 11th Mar (Sniper: "One shot, one kill". Machinegunner: "One shot, one kill...again, & again & again".)
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To: wyattearp

Did kinda stink up the place didn't it. LOL


13 posted on 09/14/2005 4:14:15 PM PDT by DoughtyOne (US socialist liberalism would be dead without the help of politicians who claim to be conservative.)
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To: Royal Wulff
"How are you going to stop a trillion tons of rock and make it suddenly move backwards?"

Several trillion tons, I think. The Juan de Fuca plate is about 80,000 sq miles in area. A layer about 15 or 20 feet deep would weigh a trillion tons -- the plate is several miles thick. Large as it is, the plate is just a thin crust floating on the mantle and molten core.

When the "big one" hits, it won't be pretty. All of us living in the area are just playing the odds -- like people along the San Andreas fault are, or like people in New Orleans were.
14 posted on 09/14/2005 4:20:07 PM PDT by USFRIENDINVICTORIA
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To: DoughtyOne
More evidence of global worming...

How is that done?

15 posted on 09/14/2005 4:36:19 PM PDT by CCCnative (waiting for socialism to fail in Santa Cruz as it did in Soviet Russia)
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To: coconutt2000

And because they have information that dates only one prior event. That information is based upon core samples of cedar trees that were submerged after the last quake. The link between that and the great tsunami is largely anecdotal (journals of a Japanese emperor at the time that described the tsunami though it could have been caused by another undersea quake around the same time).

Once again, science is shaming itself by trying to establish trends based upon little precedence, as they are doing with global warming.


16 posted on 09/14/2005 5:04:48 PM PDT by Ghost of Philip Marlowe (Liberals are blind. They are the dupes of Leftists who know exactly what they're doing.)
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To: Royal Wulff

By the shifting of even greater magma forces that the trillion tons of rock are floating on.

I think this is going to happen and Seattle may well be obliterated. I really doubt anyone knows when it will happen, though.


17 posted on 09/14/2005 5:08:07 PM PDT by Ghost of Philip Marlowe (Liberals are blind. They are the dupes of Leftists who know exactly what they're doing.)
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To: USFRIENDINVICTORIA
Actually, the folks down in CA are pretty safe. The San Andreas down in CA is a side-slip (north and south movement) so it will never "break off."

That same fault runs through the middle of the Puget Sound, though. And there it changes to the "break off" type, one slipping under the other.

The greatest part of the danger is twofold. First, when it slipped last time it is estimated to have slipped about 5 feet. That's huge. Forces we couldn't even comprehend. The second part is that it is a very deep quake. It lasts for several minutes and commences a wave effect of the top layers. The quake we had a few years ago lasted less than a minute and was a quick, superficial jolt. We had lots of damage. Buildings that are earthquake-reinforced are designed to withstand such a quake. The Cascadia fault quake ("the big one") will set up a wave motion that will cause the buildings in Seattle to sway. Anything over a few floors will probably crumble and fall. The really tall ones (Columbia Tower) will probably snap low and fall like a Douglas Fir. I'm no expert on this subject. This is based upone what I have read about it. Any corrections/additions are welcome.
18 posted on 09/14/2005 5:14:09 PM PDT by Ghost of Philip Marlowe (Liberals are blind. They are the dupes of Leftists who know exactly what they're doing.)
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To: Esther Ruth

Bush's Fault.


19 posted on 09/14/2005 5:18:34 PM PDT by sourcery ("Compelling State Interest" is the refuge of judicial activist traitors against the Constitution)
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To: Esther Ruth

Well now...glad I am going to Idaho for the weekend just in case Oregon breaks off and falls into the Pacific.


20 posted on 09/14/2005 5:19:21 PM PDT by Busywhiskers ("...moral principle, the sine qua non of an orderly society." --Judge Edith H. Jones)
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To: CCCnative; DoughtyOne
How is that done?

Oh come on, haven't you ever watched the "Tremors" movies on the Sci Fi channel?

21 posted on 09/14/2005 5:41:50 PM PDT by Bernard Marx (Don't make the mistake of interpreting my Civility as Servility)
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To: Esther Ruth

Sounds like a dance: "Seismic slip, let your backbone flip" ...


22 posted on 09/14/2005 5:43:16 PM PDT by BunnySlippers (Death to Islamo-Fascists ...)
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To: CyberCowboy777; Baynative

Shakey ping.


23 posted on 09/14/2005 5:47:04 PM PDT by DaughterOfAnIwoJimaVet
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To: Esther Ruth

"An important seismic event imperceptible to humans..."

Just keep an eye on your local rodents. When you see rats scrambling for safety, you can be assured something big is coming your way. (And I don't mean Fat Teddy!)

Don't ask me how I know this, as my reasoning skills are imperceptible to other humans. ;)


24 posted on 09/14/2005 5:47:25 PM PDT by Diana in Wisconsin (Save The Earth. It's The Only Planet With Chocolate.)
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To: Busywhiskers
My son reminds me that I'm living just north of the former bed of Lake Bonneville. That little puddle in northern Utah is a leftover.


25 posted on 09/14/2005 6:24:51 PM PDT by Myrddin
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To: Myrddin

The fault could move backwards if you think of it as chunks along each side of the fault. There is never a solid piece on either side of a fault line. A fault line is never straight, but is a series of jagged sections, 5 miles long, 100 miles long which do the actual slipping when an earthqauke happens.

One side of the fault (the Pacific plate) is moving North, the other (the North American plale) is more-or-less stationary. The stationary continental side, or more accurately a section of it, can be pushed so far north by being locked up against the Pacific side, that it eventually slips backward, either slowly like in this case, or all at once like in a big earthquake.

The pressure can build so much that if both sides are still locked enough together, both sides of the fault line move backwards.

But to me this means that the pressure is built up so much that a big quake can happen (especially considering the length of the sections moving.)


26 posted on 09/14/2005 6:44:26 PM PDT by JustDoItAlways
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To: Esther Ruth

Obviously Bush's fault.

He should apologize and take responsibility immediately.


27 posted on 09/14/2005 6:50:53 PM PDT by ovrtaxt (Stop the looting! The IRS hates competition.)
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To: Diana in Wisconsin

Oh Great! I live 30mi East of Seattle, and I saw two rats cross the road today heading NE, I also saw the same thing last week.


28 posted on 09/14/2005 6:50:55 PM PDT by cmsgop ( I DON'T C.A.I.R. !!!!!!!!!)
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To: Ghost of Philip Marlowe
You could add liquefaction in areas built on sediment, such as parts of greater Vancouver. Whole buildings will just sink, like they're built on quicksand.

At least if you're sucked below ground by liquefaction you'll miss the tsunami -- which will be enormous.

Time to go back to my normal state of denial.
29 posted on 09/15/2005 9:39:38 AM PDT by USFRIENDINVICTORIA
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To: SunkenCiv

Ping.


30 posted on 09/18/2005 6:30:32 PM PDT by blam
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To: Esther Ruth

I had slow creep once. Went to the pharmacy and bought some meds and now my creep is back to normal speed.


31 posted on 09/18/2005 6:33:11 PM PDT by devane617
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To: cmsgop
Oh Great! I live 30mi East of Seattle, and I saw two rats cross the road today heading NE, I also saw the same thing last week.

And?

I thought WA was polluted with demoncrats.

32 posted on 09/18/2005 6:35:29 PM PDT by Thumper1960 ("It is true that liberty is precious; so precious that it must be carefully rationed."-V.I.Lenin)
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To: USFRIENDINVICTORIA
I've been hoping the big one does not occur during flood and storm season. Or when I'm out of town, the laundry is not done or my gas tank & wallet are low. Keeping my gas tank & wallet topped at the same time hasn't been a common occurrence lately.
33 posted on 09/18/2005 6:59:12 PM PDT by Cold Heart
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