Godlike Productions - Conspiracy Forum
Users Online Now: 3,129 (Who's On?)Visitors Today: 1,120,001
Pageviews Today: 1,712,021Threads Today: 579Posts Today: 10,028
01:21 PM


Rate this Thread

Absolute BS Crap Reasonable Nice Amazing
 

Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought

 
Not My Fault
User ID: 737555
United States
08/16/2009 01:36 PM
Report Abusive Post
Report Copyright Violation
Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought
www.bellinghamherald.com/102/story/1029868.html


Fair use applies:

Using sophisticated seismometers and global positioning systems, scientists have been able to track minute movements along two massive tectonic plates colliding 25 miles or so underneath the Puget Sound basin.

Their early findings suggest a mega-earthquake could strike closer to Tacoma and Seattle than earlier thought.

The deep tremors, which can't be felt by humans, routinely occur every 15 months or so and can continue for more than two weeks before dying back to undetectable levels.

The instruments are detecting an inch or two of movement - known as "episodic tremor and slip" - as the Juan de Fuca plate grinds and sinks beneath the North American Plate. Closer to the surface, the two plates are locked together. When they snap, scientists say, the result could be a 9.0 or greater earthquake and a massive tsunami.

But where once they predicted a mega-earthquake would be centered just off the Northwest coast, the scientists, using data from the tremors research, now say it could be 30 miles or more inland, under the Olympic Peninsula.

"The closer you are to the source, the stronger the shaking," said Steve Malone, a research professor emeritus at the University of Washington.

Exactly how much stronger and how much more damage such a quake would cause in the Puget Sound area has not been calculated, Malone said.

While there is still plenty of debate about the findings within the scientific community, and while they may not be consistent with the models geologists have developed, state officials are aware of the latest studies.

"People are aware of the possibility," said John Vidale, a professor of geophysics at the University of Washington and the state's seismologist. "We haven't exactly calculated the impact, but bringing the fault closer (to metropolitan areas) could increase the shaking."

Earlier calculations creating a virtual earthquake using a supercomputer indicated that such a mega-earthquake in the Northwest could result in ground motion of 1.5 feet per second in Seattle, nearly six inches per second in Tacoma, Olympia and Vancouver, and three inches in Portland, Ore. That would be more than enough to cause major damage.

But the virtual earthquake was modeled on the fault being offshore, not one nearly within sight of Puget Sound's metropolitan areas.

"If we are right, it could be a lot stronger," said Malone.

Scientists have spent years studying what is known as the Cascadia subduction zone, an area where the two tectonic plants collide, stretching roughly 600 miles off the Pacific coast of northern California to southern British Columbia.

As the Juan de Fuca plate slides under the North American plate, they can become locked. When plates become locked, pressure builds. The pressure is released in what scientists call a megathrust earthquake, which can easily be magnitude 9.0. The Sumatra-Andaman Islands earthquake the day after Christmas 2004 was a 9.2 megathrust earthquake that produced a devastating Indian Ocean tsunami.

The last megathrust earthquake along the Cascadia subduction zone, estimated at 9.2, was in January 1700. It produced a tsunami that reached Japan. Cascadia subduction zone megathrust earthquakes happen on average every 400 to 500 years, but they can happen as little as 300 years apart or as much as 800 years.

A megathrust earthquake would be different than those that shake the Northwest occasionally. Those come along seismic faults that aren't believed to be tied directly to plate tectonics.

Since the deep tremors were first detected 15 years ago, scientists have been trying to determine what was causing them along the Cascadia subduction zone. Eventually, they concluded the tremors reflected the slippage of the Juan de Fuca plate under the North American plate.

"It's a burst of noise that can go on for up to 24 hours over a period of several weeks," said Herb Dragert, a geophysicist with the Geological Survey of Canada in Victoria, B.C., who was among those who first developed the theory.

What is unique about the deep tremors, which occur in an area stretching from roughly Olympia to Vancouver Island, is that they reappear roughly every 15 months. While tremors have been detected elsewhere along the Cascadia subduction zone, none are as regular or prolonged as those in the Puget Sound basin, Dragert said.

According to the timetable, episodic tremor and slip should be going on just about now. But instead it came this spring, catching scientists by surprise. Malone said some tremors were detected southwest of Olympia last week, but it was too soon to determine if they were part of a new episode or just isolated ones.

If all the energy associated with tremors over two weeks released in just 10 seconds, Vidale said, it would equal a 7.0 earthquake.

Seismographs and other equipment detecting tremors, earthquakes and other ground movements are located at more than 300 stations around the region.

The slippage the tremors are associated with is also adding pressure to the locked zone closer to the surface of the earth, Dragert said.

"Every 15 months it's like tightening the guitar string a little more," Dragert said. "You don't know whether it will take it beyond the break zone."

The deep tremors are being tracked at other subduction zones around the globe, including in Japan, Mexico, Chile and Alaska.

In the Northwest, the tremor and slip zone represents the "deepest and most landward limit" of where a mega-rupture along the subduction zone could occur, Dragert said.

"If the tremors mark the edge of the lock zone," Malone said, "it would be under the Olympics."

Dragert, Malone and Vidale all say they have come a long way over the past decade in understanding the deep tremors.

"We need to know a lot more," Dragert said.
[link to earthweb.ess.washington.edu]
Dr. Quibble

User ID: 744314
United Kingdom
08/16/2009 02:06 PM
Report Abusive Post
Report Copyright Violation
Re: Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought
bump
Dr., 1. To alter and make impure, as with the intention to deceive

Quibble, 1. To evade the truth or importance of an issue by raising trivial distinctions and objections.

Dr. Quibble
To alter and make impure the evasion of truth or importance of an issue with the intention to deceptively raise trivial distinctions and objections.

Not everything in this world is serious... some of it is a joke.

"Cursed with being wickedly british"
"Narcissist" - I wear it like a medal.
It is infact the sane that are weak with closed minds, only those outside the norm can see the truth.
Anonymous Coward (OP)
User ID: 737555
United States
08/16/2009 02:16 PM
Report Abusive Post
Report Copyright Violation
Re: Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought
bump
 Quoting: Dr. Quibble

Thanks for the bump:)


I didn't realize how many tremors in the Seattle area, until I looked at that map I posted! WOW, any time now!
mandit
User ID: 749836
United States
08/16/2009 02:22 PM
Report Abusive Post
Report Copyright Violation
Re: Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought
And i sit on Whidbey Island in the middle of Puget Sound.
Anonymous Coward
User ID: 749762
Israel
08/16/2009 02:27 PM
Report Abusive Post
Report Copyright Violation
Re: Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought
well, DAYAM Dr Quibble!
Yer info is in english!
Anonymous Coward (OP)
User ID: 737555
United States
08/16/2009 02:48 PM
Report Abusive Post
Report Copyright Violation
Re: Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought
And i sit on Whidbey Island in the middle of Puget Sound.
 Quoting: mandit 749836

Oh dear! I hope you have a boat!
Anonymous Coward
User ID: 468050
United States
08/16/2009 03:15 PM
Report Abusive Post
Report Copyright Violation
Re: Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought
And i sit on Whidbey Island in the middle of Puget Sound.
 Quoting: mandit 749836

Is the OHT still there, and do they still have quarter beer night on Thursdays?
RUSH
User ID: 732402
United States
08/16/2009 03:20 PM
Report Abusive Post
Report Copyright Violation
Re: Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought
Don'tcha just love it here.. anytime now. Remember the little one's in 93 and 2001. wild ride comming to a neighborhood near you


Auburn, and Gig Harbor here

Rush
itdincor

User ID: 588013
United States
08/16/2009 03:20 PM
Report Abusive Post
Report Copyright Violation
Re: Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought
So, in the '70s, I lived in Seattle, Queen Anne Hill, and went to college at Shoreline CC. In geology classes I learned the following.

All the hills, or at least most of them, in the Seattle area are solid rocky cores with a thick layer of gravel, sand, and other detritus left behind by the last glaciation. Give it all a real good shake and that relatively loose material comes off the rocky core, and goes down.

This is for Queen Anne hill, Capitol hill, downtown, etc. As anyone who lives in Seattle knows, these hills have very steep sides where excavation/construction has occurred over the decades. For example, downtown by the Farmer's Market, there is a western slope about a hundred or so feet high, which is nearly vertical, and lightly stepped, with little strength or support. Same for the East side of Queen Anne hill, and it's nearly so steep for the West side of Queen Anne hill. Shake 'em hard and down they go, in a slide of gravel and buildings.

Other eminences, such as Capitol hill, are not nearly so endangered, yet even so everything sits on a layer of what is, essentially, loose rubble, not solid rock.

Down by Old Town, all is built on the remains of a salt marsh. Shake this, it liquifies, and all buildings sink more or less straight down.

What I'm saying is that a major earthquake in the Seattle area could pretty much destroy the downtown area, and nearby neighborhoods on the hills.

Actually, it's all a rather dangerous place to live. But then, where isn't, really?

hayseed
RUSH
User ID: 732402
United States
08/16/2009 03:25 PM
Report Abusive Post
Report Copyright Violation
Re: Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought
NO KIDDING..ya the one in 01 shook the crap out of DTWN but i lived in Ballard at the time and no evidence at my place it even happened.. all the geo stuff..well aware of it hobby stuff and all

Rush
Anonymous Coward
User ID: 660194
United States
08/16/2009 04:26 PM
Report Abusive Post
Report Copyright Violation
Re: Deep tremors suggest mega-quake could hit closer to Seattle, earlier then thought
hf