(ORDO NEWS) — It is no secret that Africa is slowly but surely splitting in half. In the east, the continent is cut by one of the largest faults in the world. However, despite its incredible size, scientists still know surprisingly little about the complex motion of this incredible deformation, reported by the IFLScience.
In a new study, scientists from the Virginia Tech College of Science used GPS maps and computer modeling to learn more about the nature of this fault. This is the East African Rift System (EARS), which is an active continental rift zone that runs down for thousands of kilometers from north to south through Ethiopia, Kenya, Uganda, the Democratic Republic of the Congo, Tanzania, Mozambique, Malawi, Rwanda, Zambia and Rwanda.
In essence, the EARS is a crack in the African plate, which is capable of literally splitting the continent in two: the smaller Somali plate and the larger Nubian plate. It is known that the fault widens extremely slowly — literally millimeters per year. It will eventually take millions of years for the final rift to occur.
However, it attracts the attention of researchers because it is seismically active and affects the environment. For example, in places where the lithosphere is stretched especially thin, huge cracks can form in the ground and earthquakes often occur.
According to Sarah Stamps, associate professor of earth sciences at the Virginia Tech College of Science, when we’re standing on Earth, it can seem extremely solid to us. However, in reality, the Earth’s lithosphere behaves differently on different time scales.
Today, there are two main theories about how EARS moves. The first is related to lithospheric buoyancy forces, and the second to much deeper forces, namely the way the Earth’s mantle flows horizontally deep beneath East Africa.
In the new study, Stamps and his colleagues used computer models and GPS data to map the movement of the surface down to the millimeter. The researchers examined the resulting data and concluded that the EARS is driven by both surface lithospheric forces and deeper mantle forces. However, both of these forces act in completely different ways.
Buoyant forces of the lithosphere contribute to the propagation of the rift from east to west, which is directed perpendicular to the fault. At the same time, other forces act on the rift in a parallel direction, from north to south, thanks to the African superplume, a feature deep under southwest Africa, which brings a flow of mantle material from the core-mantle boundary.
In simple terms, part of the fault movement is caused by the movement of mantle material deep in the Earth’s interior, while the other part is split by the forces of the lithosphere. According to study co-author Tahiri Rajaonarison, a postdoctoral researcher at the New Mexico Institute of Technology, the new findings confirm previous findings, but also indicate that anomalous deformation may have occurred in East Africa.
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