Dec 1st, 2016: You've Got, Some Crust

[xoxoxoBruce]

Hey Earth, I'm talking about you, being all secretive under there. We haven't seen most of the bottom of
the ocean, no less the hanky panky under the land. Now every school kid knows the continents float around.
Slowly, thankfully. We've drilled holes all over and they've figured out subduction causing mountains and
earthquakes. But despite that our knowledge about the earth has grown exponentially a lot of it is speculation
and theory nobody has disproved yet.
You know, pics or it ain't happening.



Well, they're working on it.

Now, the complete x-ray of Earth’s interior is coming into focus. Next month, at a meeting of the American
Geophysical Union in San Francisco, California, a team of Dutch scientists will announce a catalog of 100
subducted plates, with information about their age, size, and related surface rock records, based on their
own tomographic model and cross-checks with other published studies. “Step by step we went deeper and
deeper, older and older,” says Douwe van Hinsbergen, a geologist at Utrecht University in the Netherlands,
who led the project along with Utrecht geologists Douwe van der Meer and Wim Spakman.

That has only recently become possible, as the underlying technique, mantle tomography, is plagued
with uncertainties. It relies on millions of seismic waves received by sensors scattered unevenly around
the world. Waves with faster arrival times are assumed to have passed through the colder rock of subducted
slabs. But seismometer coverage is patchy; earthquakes—the sources of the seismic waves—don’t occur
everywhere; and the waves get fuzzier as they pass near the core or travel long distances. “Very often for
regions that have the most interesting structures, you have the most uncertainty,” says Ved Lekic, a
tomographer at the University of Maryland in College Park.

Academic groups around the world use more than 20 models to interpret tomographic data, and their
pictures of the mantle and its structures often conflict.

Like I said, that haven't been proven wrong yet, but I guess it's better than driving a bunch of stakes with
little red flags and waiting a million years.

link