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Weather in Earth's Mantle and Core Different Than Thought

Dec 17, 2015 03:52 PM EST
Measuring weather in the Earth's mantle
This is a tomogram, or measurement of penetrating waves, of the lowest part of the Earth's mantle near Australia's equatorial region. The blue regions are the regions of high velocity and the red regions show the low velocity.
(Photo : Hrvoje Tkalcic)

Weather, weather everywhere. The movements at the Earth's center, 3,000 kilometers below the Earth's surface, are up to activities we never knew, says a new study.

In fact, where the mantle meets the core is "like a planet within a planet" and "harder to study than the center of the sun," Hrvoje Tkalči, a geophysicist with The Australian National University (ANU), said in a release.

Learning more about that area will give us clues to how the Earth formed, the research team said in the release.
Lower mantle temperatures reach around 3,000-3,500 degrees Celsius.

In order to learn more, the researchers looked at more than 4,000 seismometer measurements derived from earthquakes around the world. They knew, for instance, that temperature and material property variations (density, chemical composition) affect the speed of waves moving through the Earth.

Then the team learned, with something similar to a CT scan of that area, that seismic speeds were much different than expected and probably were caused to change by heat transfer across the boundary between the core and mantle, and by radioactivity.

"These images will help us understand how convection connects the Earth's surface with the bottom of the mantle," said Tkalči in the release.

Their research was recently published in the journal Scientific Reports

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