Earth’s “solid” inner core seems to be changing its structure, according to scientists in the United States.
A study by the University of Southern California found evidence of change near the surface of the core.
Professor John Vidale said inner core changes had long been a topic of debate, however, most research had been focused on assessing rotation.
“What we ended up discovering is evidence that the near surface of Earth’s inner core undergoes structural change,” Professor Vidale said.
He said the inner core, located almost 5000km below the Earth’s surface, was anchored by gravity within the molten liquid outer core.
Professor John Vidale said until now the inner core was widely thought of as a solid sphere.
He said the original aim of the scientists was to further chart the slowing of the inner core.
“But as I was analyzing multiple decades’ worth of seismograms, one dataset of seismic waves curiously stood out from the rest.
“Later on, I’d realize I was staring at evidence the inner core is not solid.”
He said the study utilized seismic waveform data, including 121 repeating earthquakes from 42 locations near Antarctica’s South Sandwich Islands between 1991 and 2024, to give a glimpse of what takes place in the inner core.
Read the full study: Annual-scale variability in both the rotation rate and near surface of Earth’s inner core.
