doi.org/10.1785/0320260001
Credibility: 989
#Core
Scientists have just revealed, through a global analysis of seismic data, that the lower limit of the Earth’s mantle is undergoing widespread deformation.
These changes occur exactly on the border with the planet’s outer core, an extreme region where rocks face unimaginable pressures and temperatures.
To understand it better, imagine the Earth’s structure as a giant onion.
At the center is the core, made mainly of iron and nickel, with a liquid outer part that generates the magnetic field that protects us.
Above it lies the mantle, a thick layer of hot, semi-solid rocks that move very slowly over millions of years, like a stream of thick honey.
This movement of the mantle is what drives tectonic plates at the surface, causing earthquakes, volcanoes and continental drift.
Until now, researchers were well aware of the deformations in the upper mantle, directly influenced by the drag of tectonic plates.
However, what happens in the lower mantle, right next to the core, remained a large-scale mystery.
A new study led by Jonathan Wolf of the University of California at Berkeley has changed that.
The team analyzed more than 16 million seismograms – records of seismic waves generated by earthquakes around the world – from 24 different data centers.
It was the largest compilation of its kind ever made.
They focused on shear waves that travel through the mantle, enter the core, and return.
These waves reveal seismic anisotropy, that is, variations in the speed of the waves depending on the direction in which they travel.
This anisotropy works as a kind of “fingerprint” of rocks, showing how the material was stretched, twisted or reorganized by internal currents.
The results were surprising: in around two-thirds of the regions analyzed – which cover almost 75% of the lower mantle – clear anisotropy was detected.
The most interesting thing is that these deformations are especially concentrated in areas where ancient tectonic plates, which have sunk (subducted) over millions of years, have accumulated close to the boundary with the core.
It is as if “graveyards” of ancient plates are influencing the deep flow of the mantle.
Scientists are still investigating the exact causes.
It could be a “fossil” anisotropy, preserved since when the plates were close to the surface.
Or an intense deformation caused by friction with the liquid core.
Another possibility involves changes in minerals under extreme pressure and heat, creating new internal structures in rocks.
In some areas, the signal is weak or absent, but this does not mean there is no movement – it may just be difficult to detect with current methods.
This discovery is important because it helps to better understand the general circulation of the Earth’s mantle and how it connects to processes at the surface.
Deep flow influences heat distribution, which in turn affects core dynamics and the stability of the magnetic field that protects us from solar radiation.
Geodynamic models already predicted something like this, but now there is direct evidence on a global scale.
Jonathan Wolf explained that while the upper mantle is well mapped by plate movement, the lower mantle still needed more light.
“We want to get to a large-scale understanding of flow in the deeper mantle,” he said.
In the future, with more data and analysis of anisotropy at different scales, researchers hope to map global flow directions with greater precision, as if illuminating the Earth’s interior from multiple angles.
The study, published April 1, 2026 in the journal “The Seismic Record,” represents a treasure trove of information for future research into our planet’s deep interior.
Although there is still much to discover – after all, we will never physically reach these depths – each seismic advance brings us closer to understanding how the Earth works as a dynamic, living and constantly changing system.
These mysterious movements 1,800 miles underground remind us that even below our feet, the planet remains active and full of surprises.
Over time, this knowledge could improve predictions about geological phenomena and even help to better understand the Earth’s evolution over billions of years.
Published in 04/06/2026 12h42
Text adapted by AI (Grok) and translated via Google API in the English version. Images from public image libraries or credits in the caption. Information about DOI, author and institution can be found in the body of the article.
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