After a huge crack made an appearance in the south-western Kenya, the question that lies is whether Africa is slowly splitting apart.
The lithosphere, which is the rigid outermost shell of a planet (the crust and upper mantle), is broken into tectonic plates. The Earth's lithosphere is composed of seven or eight major plates (depending on how they are defined) and many minor plates. Where the plates meet, their relative motion determines the type of boundary: convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries (or faults). The relative movement of the plates typically ranges from zero to 100 mm annually. The East African Rift system is an example of a rupture currently happening.
When the lithosphere is subject to a horizontal extensional force it will stretch, becoming thinner. Eventually, it will rupture, leading to the formation of a rift valley. This process is accompanied by surface manifestations along the rift valley in the form of volcanism and seismic activity. Rifts are the initial stage of a continental break-up and, if successful, can lead to the formation of a new ocean basin. An example of a place on Earth where this has happened is the South Atlantic ocean, which resulted from the break up of South America and Africa around 138m years ago -- ever noticed how their coastlines match like pieces of the same puzzle? Continental rifting requires the existence of extensional forces great enough to break the lithosphere. The East African Rift is described as an active type of rift, in which the source of these stresses lies in the circulation of the underlying mantle. Beneath this rift, the rise of a large mantle plume is doming the lithosphere upwards, causing it to weaken as a result of the increase in temperature, undergo stretching and breaking by faulting. Evidence for the existence of this hotter mantle plume has been found in geophysical data and is often referred to as the "African Superswell." This superplume is not only a widely accepted source of the pull-apart forces that are resulting in the formation of the rift valley but has also been used to explain the anomalously high topography of the Southern and Eastern African Plateaus.
The large fissure that still expands provoked seismic activity in the region causing the Nairobi-Narok highway to collapse. At first, the the crack was linked to tectonic activity along the East African Rift. However, according to The Guardian ''Looking at the numerous images and videos of the feature, it is clear that it does not have a tectonic origin. The two sides of the crack do not have the same outline, and much like trying to fit two pieces of a puzzle together, they do not join. Also, the crack is not fully continuous, with soil "bridges" in between. There are also no clear escarpments and the land is flat on either side of the crack. These lines of evidence show that the crack was formed by sudden erosion – not by pulling apart (extension) along active geological faults''. Still, geologists remain sceptical as to why it has formed in the location that it did and whether its appearance is at all connected to the ongoing East African Rift. For example, the crack could be the result of the erosion of soft soils infilling an old rift-related fault.
In any case, Africa will eventually split apart. Towards the Afar region the entire rift valley floor is covered with volcanic rocks. This suggests that, in this area, the lithosphere has thinned almost to the point of complete break up. When this happens, a new ocean will begin forming by the solidification of magma in the space created by the broken-up plates. Over a period of tens of millions of years, seafloor spreading will progress along the entire length of the rift.
Other Sources: Theconversation.com, Dailymail.co.uk
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