typodupeerror

## Solving an Earth-Sized Jigsaw Puzzle39

aarondubrow writes "Three years ago, researchers from Caltech and The University of Texas at Austin came together to create a computational tool that could model the Earth and answer the most pressing questions in geophysics: What controls the speed of plates? How do microplates interact? How much energy do the plates generate and how does it dissipate? Using a new geodynamics software package they developed, the researchers have modeled plate motion with greater accuracy than ever before. The project is also a finalist for the Gordon Bell Prize — high performance computing's Oscar — at this year's SC10 conference."
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## Solving an Earth-Sized Jigsaw Puzzle

• #### how is this measured? (Score:2)

The researchers are quick to point out that the project is not simply a computational success. “Models are important, but this isn’t just a modeling exercise,” Gurnis said. “The models are intimately coupled with observations, and validated as well.”

Anyone know how the measure this stuff?

• #### Re: (Score:1)

With an earth-sized measuring tape... Duhh.
• #### Re:how is this measured? (Score:5, Informative)

on Thursday September 02, 2010 @04:24AM (#33447050) Homepage

You can measure plate motions with GPS, if you're patient. Most of the deep structure is worked out using seismic imaging.

• #### Re:how is this measured? (Score:4, Insightful)

on Thursday September 02, 2010 @04:52AM (#33447148)

You can measure plate motions with GPS, if you're patient. Most of the deep structure is worked out using seismic imaging.

You don't have to be really patient... plates move at 2-10 cm/year so you'd start getting GPS data within 2-5 years, Historic data [wikipedia.org] is not too hard to get as the Magnetic stripe patterns on the spreading seafloor give data going back to the Jurassic and the mechanical/geological fit between continents gives data on the original configuration

• #### Re: (Score:2)

You don't even have to be that patient. With a GPS fiducial network you could be getting results in months rather than years.
• #### Re: (Score:2, Interesting)

You don't even have to be that patient. With a GPS fiducial network you could be getting results in months rather than years.

Does this work in practice? As I understand it a GPS fiducial network uses ground bases transmitters which would move along with the plate which at the very least would complicate the data analysis...

• #### Re: (Score:2)

Well, you need a few receivers on the same plate, but by looking at phase differences you can even detect movement within the plate. See this for example. Sure, the calculations are complex, but there are plenty of folks who don't let that put them off.
• #### Re:how is this measured? (Score:4, Informative)

on Thursday September 02, 2010 @06:20AM (#33447548)
Sorry, I must have mistyped the html on the link [gfy.ku.dk].
• #### Re:how is this measured? (Score:5, Informative)

on Thursday September 02, 2010 @04:35AM (#33447090)

Anyone know how the measure this stuff?

Short term (human lifetime) by using GPS, VLBI and measurements of seismic activity.

Long term (earth lifetime) by using magnetic stripe lineations on the seafloor, hot-spot tracks (eg, the Hawaiian volcano chain) and other geologic indicators.

http://en.wikipedia.org/wiki/Plate_reconstruction [wikipedia.org]

• #### Re:how is this measured? (Score:5, Informative)

on Thursday September 02, 2010 @05:31AM (#33447298)

GPS is the canonical answer here, but not in the form you use in your car or while hiking.

Instead they use the same setup as a surveyor who measures a piece of land:

You have one stationary receiver (the Base station) and one that you move around to measure (the Rover), while a radio link sends information from the base station to the rover.

By observation of the same set of satellites from two points you can lock on to the 1.5 GHz (20 cm wave length) carrier wave, this gives you ~10mm or better resolution within a short time.

For plate tectonics you do the same, but over significantly longer time periods to compensate for the much larger offsets between the two stations.

Before GPS you could do similar stuff with radio telescopes observing pulsars (Very Long Baseline Interferometry), but you still need very carefully synchronized clocks at the two sites, and these days GPS is used for that (i.e. clock sync) as well!

Terje

• #### Now you're beginning to understand... (Score:3, Funny)

Ah now you've uncovered the truth about the Theory of Natural Earthquakes. The whole field of geophysics is running a big scam, made to funnel money into the earthquake prediction business, give politicians more power over how we construct our buildings, and assure these "scientists" get more grant money!

Earthquakes are actually caused almost entirely by the weight of buildings placed on tectonic plates. It changes the friction between the plates, causing them to slip.

Did you ever notice that whenever an ea

• #### Why? (Score:2)

Is there any reason, if people will SILL live in California despite anything you can dig out?
• #### Re: (Score:3, Insightful)

Is there any reason, if people will SILL live in California despite anything you can dig out?

Setting aside parser errors I suppose California is only dangerous if you choose to live under an unstable pile of rocks.

• #### Re:Why? (Score:5, Insightful)

on Thursday September 02, 2010 @06:12AM (#33447496)

A large proportion of the worlds population live in earthquake or volcano zones ... ...Because that is where all the richest soils, and mineral deposits are ...

Most large cities are on the coast or on large rivers and so are prone to flooding, because they grew due to being a port

Very few cities are founded where it is safe, instead they are founded where resources are, which also turn out to be dangerous ....

People continue to live there because that's where the work is ...

• #### No doubt it'll be as accurate... (Score:2)

... as related simulations that model the weather day to day. ie it'll work alright for the first week the earth was created then the next 4 billion years in the simulation will go so far off track that by 2010 it'll be telling us that australia is at the north pole and hawaii has appeared in lake victoria.

• #### That's one reason why it's interesting (Score:3, Interesting)

These sorts of models are great because you run the model, and then see which parts of the earth don't fit in real life. You can then investigate that area more closely and either refine the model, or refine your understanding of that particular region.

I'm a geologist and most of my undergrad and graduate studies were on tectonics. What they've got here is fantastic and will yield a lot of great new research and discoveries about plate interactions. It's basically an extension of what people have been doing

• #### Re: (Score:2)

it should be able to show us all kinds of new things and ultimately a complete run-through should be possible

I'm not sure what the previous poster meant by 'complete run through', but it's in response to a probably sarcastic post about how weather predictions lose accuracy rather quickly. The reasons have nothing to do with the accuracy of the model but with chaos theory, the 'butterfly' effect. Very slight perturbations, even things happening outside the model like cosmic rays or gravitational influences of other stars, will cause slight, random, perturbations that will cascade into major differences. Change o

42 what?

• #### Meanwhile, Steven Wright claims... (Score:2)

"I have a map of the United States, life size. 1 mile equals 1 mile.

It's a bitch to fold it."

lol

• #### Re: (Score:1)

The article says they invented quite a few new algorithms from a clean sheet, so I'm guessing that they actually used an extension of F77, soooooo, it's brand new!
• #### Re: (Score:1)

Since it's a Gordon Bell prize, shouldn't it have to run on PDP-11's?
• #### Pirates? (Score:1)

...a computational tool that could model the Earth and answer the most pressing questions in geophysics: What controls the speed of plates?

My brain initially processed that as "What controls the speed of pirates?" and for very brief moment I was slightly confused...

• #### Re: (Score:1)

Why confused? It's a valid question!!!! There has to exist such a mechanism!

• #### Growing Earth (Score:1)

Will this once and for all debunk this theory?
• #### Re: (Score:2)

I used to cross swords regularly with Expanding-Earth kooks, and creationists too, on sci.geo.geology ; they're as bad as each other, and both equally prone to deliberate errors of logic, selective quoting, dodging and denying questions, etc.
It's often been said about creation-critters that "you can't reason a man out of a position which he didn't arrive at through reason." The same can be said perfectly well of EE'rs.

Disgusting bunch of fucktards, both of them ; living arguments for retroactive birth contr

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