There’s a Change Happening to Earth’s Outer Core, as Revealed by Seismic Wave Data By David Nield

[Manuel Tavares]

There’s a Change Happening to Earth’s Outer Core, as Revealed by Seismic Wave Data
By David Nield
https://rayviolet.blogspot.com/2022/07/theres-change-happening-to-earths-outer.html

Most of our knowledge about what sits at the center of our planet comes from the study of seismic waves rolling out from earthquakes. Careful analysis of these waves can reveal the composition of rocks and metal below Earth’s surface.

A new study of seismic waves propagating from two different earthquakes – in similar locations but separated by a gap of 20 years – has revealed changes that are happening in Earth’s outer core, the swirling layer of liquid iron and nickel between the mantle (the rock underneath the surface) and the inner core (the deepest layer).

The outer core and the iron contained within it directly influence our planet’s magnetic field, which in turn provides protection from space and solar radiation that would otherwise make life on Earth impossible.

That makes understanding the outer core and its evolution over time vitally important. The data recorded from four seismic wave monitors across both earthquakes showed that waves from the later event traveled around one second faster when passing through the same region of the outer core.

“Something has changed along the path of that wave, so it can go faster now,” says geoscientist Ying Zhou from Virginia Tech. “The material that was there 20 years ago is no longer there.”

“This is new material, and it’s lighter. These light elements will move upward and change the density in the region where they’re located.”...+
https://rayviolet.blogspot.com/2022/07/theres-change-happening-to-earths-outer.html