Doughnut-shaped region thousands of mile below Earth’s surface stuns scientists

In a groundbreaking discovery, researchers from the Australian National University (ANU) have discovered a doughnut-shaped region located thousands of miles beneath our feet, within the Earth’s liquid core.

It is likely to revolutionize our understanding of the Earth’s magnetic field and its significance for life on Earth. The ANU seismologists reveal that this structure within the Earth’s liquid core is exclusively found at low latitudes, positioned parallel to the equator.

The newly discovered doughnut-shaped region sits at the top of the Earth’s outer core, precisely where the liquid core meets the mantle (the layer that surrounds the Earth’s core). The researchers made the discovery through a novel approach to seismic wave analysis.

Seismic waves reveal hidden doughnut-shaped structures in Earth’s outer core

ANU geophysicist and co-author Professor Hrvoje Tkalčić noted that the seismic waves propagate more slowly through the newly identified structure compared to the rest of the liquid outer core.

“The region sits parallel to the equatorial plane, is confined to the low latitudes and has a doughnut shape. We don’t know the exact thickness of the doughnut, but we inferred that it reaches a few hundred kilometers beneath the core-mantle boundary,” he said .

The ANU researchers analyzed the similarities between waveforms many hours after the occurrence of earthquakes , which led them to make this unique discovery.

Professor Tkalčić elaborated that by comprehending the geometry of the wave paths and how they traverse the outer core’s volume, researchers can reconstruct their travel times through the Earth, confirming that the newly discovered region exhibits low seismic velocities.

Deepen our understanding of the magnetic field

The professor added that this peculiar structure remained undetected until now because previous studies collected data with less volumetric coverage of the outer core, typically observing waves confined within one hour after the origin times of large earthquakes.

“We were able to achieve much better volumetric coverage because we studied the reverberating waves for many hours after large earthquakes,” he explained .

Dr. Xiaolong Ma, the co-author of the study, noted that there are still mysteries about the Earth’s outer core that are yet to be solved. They require multidisciplinary efforts from seismology, mineral physics, geomagnetism, and geodynamics.

The researchers also believe their findings are intriguing because this low velocity within the liquid core suggests a high concentration of light chemical elements in these regions, causing the seismic waves to slow down. These light elements, along with temperature differences, contribute to stirring the liquid in the outer core.

They further explain that understanding the Earth’s outer core composition, particularly the presence of light chemical elements, is crucial for comprehending the magnetic field and predicting its potential weakening.

The researchers conclude by emphasizing that the magnetic field is a fundamental element necessary for sustaining life on the surface of our planet.

They share that the the dynamics of Earth’s magnetic field is an area of strong interest in the scientific community, and these results could promote further research into the magnetic field on both Earth and other planets.