New Map Reveals Deformation in Earth's Deep Mantle

Study links patterns of seismic anisotropy to subducted tectonic slabs

Apr. 2, 2026 at 11:45am

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A new study has created the most detailed global map yet of seismic anisotropy in the Earth's lower mantle, providing insights into the deformation of material deep within the planet. The researchers analyzed over 16 million seismograms to detect patterns of anisotropy, which they found to be concentrated in areas where subducted tectonic plates are thought to have sunk to the core-mantle boundary.

Why it matters

Understanding the deformation and flow patterns in the Earth's deep mantle is crucial for piecing together the complex convection currents that drive plate tectonics and other geological processes. This new map offers the most comprehensive view to date of how the descent of subducted slabs is shaping the lower mantle.

The details

The study, published in The Seismic Record, used an unprecedented database of over 16 million seismograms from 24 data centers around the world to analyze seismic anisotropy - the phenomenon where seismic waves travel at different speeds depending on the direction they move through a material. This anisotropy provides clues about the deformation and structure of the Earth's mantle. The researchers found anisotropy in about two-thirds of the lower mantle area they sampled, with the patterns largely corresponding to locations where subducted tectonic slabs are believed to have sunk to the core-mantle boundary.

  • The study was published on April 2, 2026.

The players

Jonathan Wolf

A researcher at the University of California, Berkeley who led the study.

The Seismic Record

The academic journal that published the study.

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What they’re saying

“We know that deformation in the upper mantle is dominated by the drag of the plates that move across it. And that extremely well approximates what we know from seismic anisotropy about the deformation of the upper mantle. But we don't have any of this kind of large-scale understanding for flow in the lowermost mantle. And that's really what we want to get at.”

— Jonathan Wolf, Researcher, University of California, Berkeley

What’s next

Researchers plan to continue mining the massive seismogram database used in this study to gain even deeper insights into the flow patterns and deformation of the Earth's lower mantle.

The takeaway

This new global map of seismic anisotropy in the deep mantle provides the clearest picture yet of how the descent of subducted tectonic plates is shaping the convection and deformation of material at the boundary between the mantle and the Earth's core.