Scientists recreate extreme conditions 1800 miles below Earth’s crust

WASHINGTON - A new study by Yale University and the University of California, Berkeley, sheds light on why certain seismic waves travel more quickly through the core-mantle boundary, a thin layer of the Earth’s interior that lies between about 1675 and 1800 miles below the surface.

Lowell Miyagi and his team have managed to heat and compress post-perovskite to the conditions found at the core-mantle boundary, where temperatures soar to nearly 6000 degrees Fahrenheit and pressures are more than one million times the ambient pressure at the surface of the Earth.

Geologists believe that most of the Earth’s mantle is made up of a mineral called magnesium silicate perovskite MgSiO3, or “perovskite” for short.

“Post-perovskite has a layered crystal structure, but instead of deforming along the layers when compressed, like almost every other layered structure does, it deforms on a plane cutting across the layers,” Miyagi said.

“The findings could explain why seismic waves tend to travel faster in certain directions near the core-mantle boundary,” said Kanani Lee, assistant professor of geology and geophysics at Yale.

“The alignment of post-perovskite’s crystal structure likely determines in which direction seismic waves travel fastest in that region. Understanding this structure gives us much more insight into the extreme physics taking place 1800 miles below the surface,” Lee added.

The findings appear in the Sept. 24 issue of the journal Science. (ANI)