Scientists have discovered “unexpected widespread structures” near Earth’s core.
Researchers analyzed thousands of recordings of seismic waves, or sound waves traveling through the Earth. Echoes from the boundary between Earth’s molten core and the solid mantle layer above it led to the discovery. “The echoes revealed more widespread, heterogenous structures—areas of unusually dense, hot rock—at the core-mantle boundary than previously known,” said the University of Maryland, which participated in the research, in a statement.
The study is published in the journal Science.
Researchers studied seismic waves traveling beneath the Pacific Ocean Basin to reveal a previously unknown structure beneath the Marquesas Islands in the South Pacific. They also found that a structure beneath the Hawaiian Islands is larger than previously thought.
“By looking at thousands of core-mantle boundary echoes at once, instead of focusing on a few at a time, as is usually done, we have gotten a totally new perspective,” said the paper’s lead author Doyeon Kim, a postdoctoral fellow in the UMD Department of Geology, in the statement. “This is showing us that the core-mantle boundary region has lots of structures that can produce these echoes, and that was something we didn’t realize before because we only had a narrow view.”
The structures lie 1,802 miles below Earth’s surface.
A machine-learning algorithm, developed by Johns Hopkins University and Tel Aviv University to find patterns in radiation from distant stars, was used to discover the echoes from what are known as shear waves.
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