New research suggests that Earth’s inner core may not be as solid as previously believed. Scientists studying seismic waveforms have discovered structural changes in the core, which challenge long-held assumptions about its composition. This discovery emerged while researchers were examining the inner core’s slowing rotation. The seismic data, gathered from multiple earthquakes over three decades, indicated unexpected wave behaviors. Experts believe these findings could provide new insights into Earth’s thermal and magnetic fields, as well as subtle variations in the planet’s rotation.

Seismic Data Reveals Core’s Malleability

According to the study published in Nature Geoscience on February 10, researchers from the University of Southern California (USC) analysed seismic data from 121 earthquakes that occurred between 1991 and 2024. These earthquakes were recorded across 42 locations near the South Sandwich Islands. While initially focused on the core’s rotational slowdown, the team observed anomalies in the waveforms, prompting further investigation. The research led them to conclude that the inner core might exhibit more movement and structural variation than previously understood.

Expert Insights on Core Behavior

John Vidale, Dean’s Professor of Earth Sciences at USC Dornsife College, told in an official release that an unusual seismic dataset stood out while analysing decades of records. He noted that the data revealed physical activity in the inner core, suggesting it is not entirely solid. Enhanced resolution techniques helped confirm these observations. Researchers believe the structural changes could be linked to the core’s slowing motion, which might even slightly affect the length of a day.

Implications for Earth’s Magnetic and Thermal Fields

Experts suggest that these findings could improve the understanding of Earth’s internal processes, particularly its magnetic and thermal fields. The discovery may refine existing models of the planet’s structure and behavior. While more research is needed, the study offers a fresh perspective on the inner workings of Earth’s core.