Abdelrahman
For many years, researchers believed that the Earth’s inner core was simply a solid metallic sphere, akin to a planet within our planet, located approximately 3,000 miles (4,828 kilometers) beneath the Earth’s surface.
However, scientists at the University of Southern California (USC) have made an unexpected finding, suggesting that the Earth’s inner core may actually be more flexible than previously thought.
John Vidale, the Dean’s Professor of Earth Sciences at USC Dornsife College of Letters, Arts and Sciences, who led the recent study, mentioned in a statement that the team did not initially set out to explore the inner core’s structural characteristics.
Initially, the USC team was focused on observing the deceleration of the inner core’s rotation. Past research indicated that the core is slowing down over time. To track this change, they utilized seismic waveform data gathered from seismic events.
The research team analyzed data from 121 recurring earthquakes between 1991 and 2024, focusing on events located around the remote South Sandwich Islands, situated north of Antarctica.
While analyzing the seismic waveforms, the USC researchers encountered intriguing data that challenged their preconceptions about the inner core. They discovered that a particular set of waveforms exhibited unexpected properties.
“During my examination of numerous years of seismogram data, one specific seismic wave dataset caught my attention,” stated Vidale. “It eventually became clear that this was evidence indicating the inner core is not entirely solid.”
As the team refined their resolution technique, they identified that the seismic waveforms “indicated additional dynamic activity within the inner core.” This prompted speculation that the inner core might exhibit some movement instead of being absolutely rigid.
“Our findings suggest that the surface area of Earth‘s inner core is undergoing structural transformations,” noted Vidale.
The researchers believe these structural changes may be linked to the decreasing rotation of the inner core and could enhance our understanding of the Earth’s thermal and magnetic fields. Additionally, they hypothesize that such changes may have “slightly altered the length of a day.”
The study was published on February 10 in the journal Nature Geoscience.
