Computer simulations conducted by geophysicist D. Sarah Stamps have shed light on the unusual deformations and seismic anisotropy detected below the East African Rift System. Stamps’ research confirms that the African Superplume is responsible for these anomalies.
Continental rifting is a process that involves the stretching and fracturing of the Earth’s lithosphere, resulting in rock fractures and earthquakes. Stamps compares the deformation styles of a rifting continent to playing with Silly Putty, explaining that the lithosphere behaves differently on different time scales.
The East African Rift System, the largest continental rift system in the world, displays both predictable rift-perpendicular deformations and anomalous rift-parallel deformations. A recent study published in the Journal of Geophysical Research utilized 3D thermomechanical modeling to explore the processes behind the East African Rift System and confirmed that northward mantle flow associated with the African Superplume drives the rift-parallel deformation.
These findings have the potential to resolve the ongoing scientific debate on the dominant plate-driving forces in the East African Rift System. Stamps’ observations using GPS measurements from satellites have added complexity to the discussion surrounding the driving forces of the rift system.
Some scientists believe that lithospheric buoyancy forces, caused by the high topography of the African Superswell and density variations in the lithosphere, primarily drive the rifting in East Africa. On the other hand, others point to horizontal mantle traction forces as the main driver.
Previous computational simulations suggested that a combination of both forces could contribute to the rift and its deformation. However, these simulations could not explain the anomalous rift-parallel deformation observed by Stamps.
The newly published study demonstrates through 3D thermomechanical modeling that the African Superplume is responsible for the anomalous deformations and rift-parallel seismic anisotropy detected beneath the East African Rift System. Seismic anisotropy, the alignment of rocks in response to mantle flow or structural fabrics, aligns with the direction of the African Superplume’s northward mantle flow, suggesting mantle flow as the source.
Understanding these processes of continental rifting, including the anomalous deformations, will contribute to unraveling the complex mechanisms behind continent breaking. The researchers are excited about the new insights provided by the numerical modeling, as it enhances understanding of the processes that shape the Earth’s surface during continental rifting.
The study titled “A Geodynamic Investigation of Plume-Lithosphere Interactions Beneath the East African Rift” was published in the Journal of Geophysical Research Solid Earth.
“Zombie enthusiast. Subtly charming travel practitioner. Webaholic. Internet expert.”