Strange movements in East Africa’s Rift Valley appear to be caused by superheated rocks deep below the Earth’s surface.

A giant superheated rock rising near the Earth’s core could help explain mysterious deformations linked to a giant rift in the planet’s surface that appears to be splitting Africa in two, according to a recent study.

Across the planet, huge cracks in the Earth’s surface, known as continental rifts, separate land masses. The largest active continental fault is the East African Rift, a network of valleys that is approximately 2,175 miles (3,500 km) long and extends from the Red Sea to Mozambique.

The continental rift is due to the deformation of the lithosphere, the most rigid layer of the planet. As the lithosphere thins, its shallower parts can deform in a variety of ways, from peeling off like dough to shattering.

The direction in which the Earth’s surface deforms along continental faults is usually at right angles to the length of a fault. Imagine two halves of a continent splitting apart, with the land stretching or breaking where the halves meet.

After studying the East African Rift for more than 12 years, the researchers found that the deformation is vertical, as expected, and moves east and west. However, they also discovered deformation parallel to the fault, moving to the north. These surface movements “are quite unusual.

In the study, the team discovered that a giant, mushroom-shaped rock with a plethora of other hot rocks rising from the Earth’s mantle may help explain these mysterious deformations.

Scientists used GPS technology to track surface movements on the East African Rift with millimeter accuracy. They also used seismic instruments to analyze the directions in which the mantle rock slowly rolled over a wide area.

Finally, 3D computer simulations developed by the study’s lead author Tahiry Rajaonarison, a geophysicist at New Mexico Tech in Socorro, analyzed GPS and seismic data to estimate the underground activity behind the East African Rift.

The 3D models showed that the unusual deformations parallel to the fault may be due to the northward flow of the mantle.