Doughnut-shaped region discovered in Earth’s liquid core

Around the giant ball of liquid metal located at the core of our planet, about 2,900 kilometers below the surface, A large “ring-shaped” region several hundred kilometers long around the equator was discovered. The structure was detected by scientists at the Australian National University (ANU), who were investigating why seismic waves travel 2% slower here than in the rest of the core.

To reach this previously undetected region, the authors used a new approach to the traditional technique, which uses seismic waves created by earthquakes as a type of ultrasound that can “see” the shape and structure of the core. Instead of analyzing the initial waves of earthquakes, they focused on the weaker, final waves.

According to research recently published in the journal Science Advances, this giant “doughnut” may contain lighter elements such as silicon and oxygen. These “neighbors” on the periodic table may play It plays an important role in generating our planet’s magnetic field by interacting with the liquid metal currents of the outer core.

Delving deep into the Earth’s core

Researchers in Australia have found that, unlike most seismic studies that focus on the first hour after an earthquake, new insights can emerge from the later, weaker moment in the waves called a “coda,” a term used in music to refer to the final section of a piece that usually concludes the work.

One thing that caught the team’s attention was how the codas were detected several hours after the earthquake. were similar in records from different seismic detectors. In a paper published in The Conversation, co-author ANU professor Hrvoje Tkalcic explained that the similarity in the final parts of seismic waves is mathematically known as the “coda-correlation wavefield”.

Because previous studies did not go that deep, literally, and looked at waves trapped within just an hour of the earthquakes’ onset times, “we were able to get much better volumetric coverage because we looked at waves that reverberated for hours after large earthquakes,” Tkalcic concluded.

How important is the “doughnut” to the Earth’s magnetic field?

The study’s authors believe that understanding more about the composition of Earth’s outer core, including its lighter “doughnut” chemical elements, is important for understanding how Earth’s magnetic field works and even being able to predict when it might weaken or stop working.

Despite its name, The so-called outer core is located inside the Earth, below the mantle but above the inner core, a solid sphere composed primarily of iron and nickel, as well as other elements such as sulfur and oxygen.

The movement of the liquid outer core is responsible for generating Earth’s magnetic field, which works like a dynamo. Tkalcic points out that “the magnetic field is a fundamental component that we need to sustain life on the surface of our planet.”

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