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Solving an Earth-Sized Jigsaw Puzzle
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."
You can measure plate motions with GPS, if you're patient. Most of the deep structure is worked out using seismic imaging.
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
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 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
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
"almost all programming can be viewed as an exercise in caching"
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 ...
Puteulanus fenestra mortis