Scientists from The Australian National University (ANU) have discovered a doughnut-shaped region within Earth’s liquid core, providing new insights into the dynamics of the planet’s magnetic field. This structure is located at low latitudes and runs parallel to the equator, remaining undetected until now. The Earth’s core consists of two layers: the inner core, which is solid, and the outer core, which is liquid. The newly discovered region sits at the top of the outer core, where it meets the mantle.
ANU geophysicist Professor Hrvoje Tkalčić explained that the seismic waves detected in this region are slower than in the rest of the liquid outer core. This doughnut-shaped region is believed to extend a few hundred kilometers beneath the core-mantle boundary and is confined to the low latitudes. The discovery was made by analyzing waveforms several hours after the origin times of earthquakes, allowing for better volumetric coverage of the outer core compared to traditional observation techniques.
According to study co-author Dr. Xiaolong Ma, this discovery helps uncover mysteries surrounding the dynamics of Earth’s magnetic field. The outer core is primarily composed of liquid iron and nickel, and the movement of the electrically conductive liquid generates Earth’s magnetic field, which protects the planet from solar winds and harmful radiation. Understanding the composition of the outer core, including the presence of light chemical elements, is crucial for predicting any changes in the magnetic field’s strength or cessation.
The low seismic speeds within the liquid core imply a high concentration of light chemical elements, slowing down the seismic waves. These elements, along with temperature variations, help stir the liquid in the outer core, influencing the Earth’s magnetic field. The magnetic field is essential for sustaining life on Earth’s surface, making it a topic of great interest in the scientific community. This discovery could lead to further research on the magnetic field not only on Earth but also on other planets, offering valuable insights into planetary dynamics.
The research published in Science Advances highlights the importance of multidisciplinary efforts from various scientific fields, including seismology, mineral physics, geomagnetism, and geodynamics, to unravel the mysteries of the Earth’s outer core. The study’s innovative approach to analyzing seismic waveforms allowed for a more comprehensive understanding of the liquid core’s structure and dynamics. The unique geometry of the newly discovered region provides valuable information about Earth’s interior processes and has implications for predicting changes in the magnetic field over time.