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Seismologists puzzle over largest deep earthquake ever recorded
UC Santa Cruz News ^ | 09/19/13 | Tim Stephens

Posted on 09/21/2013 10:35:06 AM PDT by oxcart

A magnitude 8.3 earthquake that struck deep beneath the Sea of Okhotsk on May 24, 2013, has left seismologists struggling to explain how it happened. At a depth of about 609 kilometers (378 miles), the intense pressure on the fault should inhibit the kind of rupture that took place.

"It's a mystery how these earthquakes happen. How can rock slide against rock so fast while squeezed by the pressure from 610 kilometers of overlying rock?" said Thorne Lay, professor of Earth and planetary sciences at the University of California, Santa Cruz.

Lay is coauthor of a paper, published in the September 20 issue of Science, analyzing the seismic waves from the Sea of Okhotsk earthquake. First author Lingling Ye, a graduate student working with Lay at UC Santa Cruz, led the seismic analysis, which revealed that this was the largest deep earthquake ever recorded, with a seismic moment 30 percent larger than that of the next largest, a 1994 earthquake 637 kilometers beneath Bolivia.

Deep earthquakes occur in the transition zone between the upper mantle and lower mantle, from 400 to 700 kilometers below the surface. They result from stress in a deep subducted slab where one plate of the Earth's crust dives beneath another plate. Such deep earthquakes usually don't cause enough shaking on the surface to be hazardous, but scientifically they are of great interest.

The energy released by the Sea of Okhotsk earthquake produced vibrations recorded by several thousand seismic stations around the world. Ye, Lay, and their coauthors determined that it released three times as much energy as the 1994 Bolivia earthquake, comparable to a 35 megaton TNT explosion. The rupture area and rupture velocity were also much larger. The rupture extended about 180 kilometers, by far the longest rupture for any deep earthquake recorded, Lay said. It involved shear faulting with a fast rupture velocity of about 4 kilometers per second (about 9,000 miles per hour), more like a conventional earthquake near the surface than other deep earthquakes. The fault slipped as much as 10 meters, with average slip of about 2 meters.

"It looks very similar to a shallow event, whereas the Bolivia earthquake ruptured very slowly and appears to have involved a different type of faulting, with deformation rather than rapid breaking and slippage of the rock," Lay said.

The researchers attributed the dramatic differences between these two deep earthquakes to differences in the age and temperature of the subducted slab. The subducted Pacific plate beneath the Sea of Okhotsk (located between the Kamchatka Peninsula and the Russian mainland) is a lot colder than the subducted slab where the 1994 Bolivia earthquake occurred.

"In the Bolivia event, the warmer slab resulted in a more ductile process with more deformation of the rock," Lay said.

The Sea of Okhotsk earthquake may have involved re-rupture of a fault in the plate produced when the oceanic plate bent down into the Kuril-Kamchatka subduction zone as it began to sink. But the precise mechanism for initiating shear fracture under huge confining pressure remains unclear. The presence of fluid can lubricate the fault, but all of the fluids should have been squeezed out of the slab before it reached that depth.

"If the fault slips just a little, the friction could melt the rock and that could provide the fluid, so you would get a runaway thermal effect. But you still have to get it to start sliding," Lay said. "Some transformation of mineral forms might give the initial kick, but we can't directly detect that. We can only say that it looks a lot like a shallow event."

In addition to Ye and Lay, the coauthors of the paper include Hiroo Kanamori of the California Institute of Technology and Keith Koper of the University of Utah. This work was supported in part by the National Science Foundation (grant #EAR-1245717).


TOPICS: Science
KEYWORDS: catastrophism; earthquake; seismologists; seismology

The world's largest recorded deep earthquake occurred on May 24, 2013, at a depth of 609 km in the subducting Pacific plate beneath the Sea of Okhotsk near Kamchatka, Russia, as shown in the schematic vertical cross-section above and on the map below. (Credit: diagram by L. Ye and T. Lay, map by Ye et al., Science)


1 posted on 09/21/2013 10:35:06 AM PDT by oxcart
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To: neverdem; SunkenCiv

(((Ping)))


2 posted on 09/21/2013 10:36:33 AM PDT by oxcart (Journalism [sic])
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To: oxcart
What keeps the negative electron from smashing down into the relatively positive nucleus ... ?

The Finger Of God.

3 posted on 09/21/2013 10:39:04 AM PDT by knarf (I say things that are true ... I have no proof ... but they're true)
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To: oxcart

“There will be an increase in earthquakes”


4 posted on 09/21/2013 10:40:11 AM PDT by Viennacon
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To: oxcart

gophers?


5 posted on 09/21/2013 10:41:05 AM PDT by Doomonyou (Let them eat Lead.)
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To: knarf

Do you think anyone who might want to go a little deeper into it than that is going to Hell?


6 posted on 09/21/2013 10:41:45 AM PDT by DManA
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To: oxcart

It’s obviously caused by a combination of climate change, fracking and the tea party.

Oh, racism too.


7 posted on 09/21/2013 10:42:08 AM PDT by prisoner6 ( FREEDOM!)
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To: DManA

Nope ... unless they lied to me in Junior High ... just reciting science fact.


8 posted on 09/21/2013 10:43:25 AM PDT by knarf (I say things that are true ... I have no proof ... but they're true)
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To: knarf

Did that inspire you to dig deeper? Into the science of nuclear physics?


9 posted on 09/21/2013 11:00:19 AM PDT by DManA
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To: oxcart

Proving that more stimulus money is needed to study this.


10 posted on 09/21/2013 11:07:59 AM PDT by Beowulf9
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To: oxcart
Hmm...nobody is answering the phones at CERN’s Large Hadron Collider project site.
11 posted on 09/21/2013 11:08:03 AM PDT by PowderMonkey (WILL WORK FOR AMMO)
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To: knarf

“And the harp, and the viol, the tabret, and pipe, and wine, are in their feasts: but they regard not the work of the Lord, neither consider the operation of his hands.

Therefore my people are gone into captivity, because they have no knowledge: and their honourable men are famished, and their multitude dried up with thirst.

Therefore hell hath enlarged herself, and opened her mouth without measure: and their glory, and their multitude, and their pomp, and he that rejoiceth, shall descend into it.

And the mean man shall be brought down, and the mighty man shall be humbled, and the eyes of the lofty shall be humbled: . . .” Isaiah 5:12-15


12 posted on 09/21/2013 11:17:36 AM PDT by captmar-vell
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To: captmar-vell

So you would answer my question with a yes?


13 posted on 09/21/2013 11:26:58 AM PDT by DManA
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To: Viennacon

Clearly its fracking


14 posted on 09/21/2013 11:39:35 AM PDT by StevieRay20
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To: DManA

what question? you have a question?

I have one for you, how do you put someone on ignore?


15 posted on 09/21/2013 11:46:08 AM PDT by captmar-vell
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To: DManA

“Do you think anyone who might want to go a little deeper into it than that is going to Hell?”

Well, it IS 609 km down!

As a scientist, and a Christian, I love stories like this that put the question marks in science. One, it is exciting to learn and research “new” things; and two, it should humble us when we think we know everything.


16 posted on 09/21/2013 11:57:59 AM PDT by 21twelve ("We've got the guns, and we got the numbers" adapted and revised from Jim M.)
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To: 21twelve

I think the post like the one I responded to disrespect Christian scientists who are doing good, original, valid work in all the sciences.

At least it comes across like that to me.


17 posted on 09/21/2013 12:01:21 PM PDT by DManA
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To: captmar-vell

Well, you could improve things by not posting to threads that you aren’t prepared to discuss.


18 posted on 09/21/2013 12:07:45 PM PDT by DManA
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To: oxcart

What? Something as simple as a single earthquake and the

SCIENCE ISN’T SETTLED???


19 posted on 09/21/2013 12:09:34 PM PDT by SaxxonWoods (....Let It Burn...)
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To: DManA
Nope .. I just remember the simplicity of the universe God gave us ... I don't question much of what does not innately enter in and register as valid.

Some call it the spirit of discernment.

20 posted on 09/21/2013 12:19:42 PM PDT by knarf (I say things that are true ... I have no proof ... but they're true)
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To: knarf

Care to comment on my #17?


21 posted on 09/21/2013 12:30:15 PM PDT by DManA
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To: DManA
I would if I thought it was directed to me.

I'm not sure why you and I are having this back and forth ... My original comment was to the comment in the article that they didn't understand how the earthquake could happen under so much pressure.

My comment was ... Cause God said so.

(That's in the original Chaldean)

From there it sort of sideslipped ...

What keeps the negative electron from smashing down into the relatively positive nucleus ... ?
The Finger Of God.

to: knarf
Do you think anyone who might want to go a little deeper into it than that is going to Hell?

To: DManA
Nope ... unless they lied to me in Junior High ... just reciting science fact.

] To: knarf
Did that inspire you to dig deeper? Into the science of nuclear physics?

! To: DManA
Nope .. I just remember the simplicity of the universe God gave us ... I don't question much of what does not innately enter in and register as valid.
Some call it the spirit of discernment.

To: knarf
Care to comment on my #17?


As you can see ... our conversation is a little fractured.

22 posted on 09/21/2013 12:53:11 PM PDT by knarf (I say things that are true ... I have no proof ... but they're true)
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To: DManA

It does. I’m reminded of the time I couldn’t answer some question on a test back in college, and put down something like “God did it”. My prof didn’t think it was the right answer either!


23 posted on 09/21/2013 12:54:40 PM PDT by 21twelve ("We've got the guns, and we got the numbers" adapted and revised from Jim M.)
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To: oxcart
Sounds like the Old Ones to me.


24 posted on 09/21/2013 12:56:44 PM PDT by PLMerite (Shut the Beyotch Down! Burn, baby, burn!)
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To: Doomonyou

Say, isn’t that where the USN regularly put a tap on a Soviet underwater communications cable? (pre optical...)


25 posted on 09/21/2013 1:02:19 PM PDT by Calvin Locke
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To: knarf
I just remember the simplicity of the universe God gave us

It's only simple if you don't bother to examine it. That is why I say you disrespect scientists, including Christian scientists, who expend great energy, time and brain power and who are slowly tweezing it all out.

And it disrespects the Creator of it all who gave it to us to enjoy and examine.

26 posted on 09/21/2013 1:02:56 PM PDT by DManA
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To: knarf

Science is their God and arrogance is their toolset, and to quote his word in their ‘holy place’ is and abomination to them,

and its not your or I they don’t like, and that’s the only reason i chimed in,

I should’ve html underlined this part,

And the mean man shall be brought down, and the mighty man shall be humbled, and the eyes of the lofty shall be humbled: . . .” Isaiah 5:12-15


27 posted on 09/21/2013 1:10:05 PM PDT by captmar-vell
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To: DManA
Wow.

If you WANT to make it difficult and complicated, by all means .. have at it.

But is it Christian to chasten a born again believer who just ..... believes?

Mary Baker Eddy would chasten YOU.

28 posted on 09/21/2013 1:11:56 PM PDT by knarf (I say things that are true ... I have no proof ... but they're true)
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To: oxcart
The presence of fluid can lubricate the fault,

I feel a country western song lyric stirring in me

29 posted on 09/21/2013 2:09:08 PM PDT by beebuster2000
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To: oxcart

The earth is twerking!


30 posted on 09/21/2013 2:13:08 PM PDT by COBOL2Java (I'm a Christian, pro-life, pro-gun, Reaganite. The GOP hates me. Why should I vote for them?)
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To: captmar-vell
I hadn't picked up on the CS line at the time ... I wasn't sure what you were saying to whom

Thanx ... appreciate it.

31 posted on 09/21/2013 4:11:44 PM PDT by knarf (I say things that are true ... I have no proof ... but they're true)
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To: oxcart; 75thOVI; agrace; aimhigh; Alice in Wonderland; AndrewC; aragorn; aristotleman; ...

Thanks oxcart.
At a depth of about 609 kilometers (378 miles), the intense pressure on the fault should inhibit the kind of rupture that took place. "It's a mystery how these earthquakes happen. How can rock slide against rock so fast while squeezed by the pressure from 610 kilometers of overlying rock?" said Thorne Lay, professor of Earth and planetary sciences at the University of California, Santa Cruz.



32 posted on 09/21/2013 5:49:12 PM PDT by SunkenCiv (It's no coincidence that some "conservatives" echo the hard left.)
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To: SunkenCiv
How can rock slide against rock so fast while squeezed by the pressure from 610 kilometers of overlying rock?"

I don't know. But I bet it makes for a big earthquake.

33 posted on 09/21/2013 6:52:57 PM PDT by BenLurkin (This is not a statemet of fact. It is either opinion or satire; or both.)
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To: oxcart

Pressure induced metamorphic change of structure with reduction of volume and attendant shock wave.


34 posted on 09/21/2013 9:41:16 PM PDT by Ozark Tom
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