Plate Nº 29 · recorded October 10, 2026
Earth & ClimateReported finding
African Superplume May Be Reshaping the East African Rift from Below
3D computer models link unusual northward motion along the East African Rift to the African Superplume, a vast upwelling of hot rock rising from deep inside Earth.
By Nathan Brooks3 min read625 words
In brief
- Study published September 1, 2026, in the Journal of Geophysical Research by Virginia Tech researchers
- Team analyzed more than 12 years of GPS data from stations receiving signals from 30+ satellites at roughly 25,000 km altitude, tracking motion at the millimeter scale
- The African Superplume begins deep beneath southwest Africa and extends northeastward, growing shallower along the way
- A 2021 study in Geophysical Research Letters first suggested both lithospheric buoyancy and mantle traction forces contribute to East African Rift deformation
- The East African Rift is the largest continental rift system on Earth
A 3D computer model has linked unusual surface motion along the East African Rift to a vast upwelling of hot rock deep inside the planet, according to a study published September 1, 2026, in the Journal of Geophysical Research.
Researchers at Virginia Tech used more than 12 years of GPS measurements from stations that receive signals from more than 30 satellites orbiting roughly 25,000 kilometers above Earth. Those readings tracked ground movement at the millimeter scale. They found that parts of East Africa are shifting not only in the expected direction—perpendicular to the rift—but also in a puzzling parallel direction running along it.
What is the African Superplume?
The African Superplume is a massive zone of rising mantle material that begins deep beneath southwest Africa and grows shallower as it extends northeast across the continent. In the new study, researchers show that the northward flow of this plume can produce the unexplained parallel motion at the surface.
How do shallower forces fit in?
Continental rifts form when Earth's rigid outer shell, the lithosphere, stretches and thins. Scientists have long debated what drives the East African Rift. Two main candidates exist:
- Lithospheric buoyancy forces, tied to differences in elevation and density within the lithosphere. In East Africa, the African Superswell—a broad region of unusually high topography—plays a role.
- Mantle traction forces, which arise from flowing rock beneath the rigid plate.
A 2021 study by the same team found that both could contribute. Buoyancy forces accounted for the expected cross-rift motion, but not the parallel component.
What did the new model show?
Lead author Tahiry Rajaonarison, a postdoctoral researcher at New Mexico Tech who earned his Ph.D. at Virginia Tech, ran 3D thermomechanical simulations focused on the unexplained parallel deformation. The models showed that northward mantle flow tied to the African Superplume could produce it.
The simulations also reproduced rift-parallel seismic anisotropy—a pattern in which seismic waves travel at different speeds depending on direction. That orientation matches the superplume's flow, giving researchers a second, independent line of evidence for the deep connection.
Why does the lithosphere behave this way?
Geophysicist D. Sarah Stamps, associate professor in Virginia Tech's Department of Geosciences, compared the lithosphere to Silly Putty. "If you hit Silly Putty with a hammer, it can actually crack and break," Stamps said. "But if you slowly pull it apart, the Silly Putty stretches. So on different time scales, Earth's lithosphere behaves in different ways."
Near the surface, rocks fracture, producing faults and earthquakes. Deeper down, hotter material deforms more gradually.
What does this mean for understanding continental breakup?
The East African Rift is the largest continental rift system on Earth and a natural laboratory for studying how continents begin to break apart. The new findings suggest that shallow and deep forces both shape the process.
"We're excited about this result from Dr. Rajaonarison's numerical modeling because it provides new information about the complex processes that shape the Earth's surface through continental rifting," Stamps said.
Rajaonarison added: "We are saying that the mantle flow is not driving the east-west, rift-perpendicular direction of some of the deformations, but that it may be causing the anomalous northward deformation parallel to the rift. We confirmed previous ideas that lithospheric buoyancy forces are driving the rift, but we're bringing new insight that anomalous deformation can happen in East Africa."
The study builds on the 2021 paper but does not settle the broader debate. The models are simplifications of a system that also includes pockets of melt and ancient structures within the lithosphere. Researchers say additional observations and refined simulations will be needed to fully separate the contributions of shallow and deep forces.
via agupubs.onlinelibrary.wiley.com (Original)
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