By David STEIN
An impressive sinkhole has appeared in southwestern Kenya following heavy rains. Scientists see it as another sign of the gradual break-up of the African continent.
The events giving rise to this news took place on the morning of March 19, 2018. A gigantic fault appeared in the middle of the Mahiu-Narok road in Kenya. Descending to more than 15 meters deep and spanning 3 kilometers in length, this impressive scar follows the heavy rains that hit the country at the time.
According to geologists, it is likely that the fissure existed before and was filled with volcanic ash from nearby Mont Longonot. The rainwater would then have washed away the ashes, leaving the scar. However, this could be the mark of a much deeper and more spectacular phenomenon: the split of the African continent.
Frequent tectonic activity, a sign of profound changes
This is not the first time that the Mahiu-Narok road has been damaged. Once again, the road was filled in to allow traffic to resume as quickly as possible. However, this temporary solution may not be enough in the long run. Julius Korir, the infrastructure manager explains:
There seems to be a weakness in this area.
Researcher Lucia Perez Diaz of Royal Holloway at the University of London written on The conversation:
Earth is an ever-changing planet, although in some ways the changes driving it seem almost invisible to us. But every now and then something dramatic happens that causes researchers to question again how the African continent splits in two.
When the planet is torn apart
The Earth’s lithosphere is formed by the crust and the upper part of the mantle of our planet. This structure is divided into several tectonic plates, which move relative to each other. The forces that cause these movements can also cause some plates to rupture and create new islands above the waves, drifting over the asthenosphere.
When the lithosphere is subjected to a force of horizontal extension, it stretches and thins. It will eventually fracture, leading to the formation of a rift valley.
This process is accompanied by increased volcanic and seismic activity and, if continued successfully, may lead to the formation of a new ocean basin.
This is what happened about 138 million years ago when Africa and America parted ways to form the Atlantic Ocean. And that’s what’s happening now in the great rift valley, a geological feature stretching nearly 3,000 kilometers between the Near East and Southern Africa. This rift valley cut the Horn of Africa in two to the east, giving rise to the Nubian Plate on one side and the Somali Plate on the other.
A multiple Africa is on the way
This rift (tearing of the lithosphere), which began around 20 million years ago in the Miocene, may well lead to the individualization and oceanization of the Somali Plate in the next million years. In short, Africa may well be split in two. This geological activity “became visible when this great fault appeared in southwestern Kenya,” explains Perez Diaz.
The weakening of the lithosphere in the Great Rift Valley is caused by a plume in the asthenosphere, the layer below the lithosphere. This pocket of magma presses against the asthenosphere and this pressure, combined with an increase in heat, weakens the lithosphere, stretches it and will eventually cause it to fracture.
At present, it is difficult to say whether the crack that has appeared in Kenya is a direct result of this rift system. It could also be linked to volcanic activity in the area, which itself is the result of the rifting process. In any case, there is no reason to be alarmed: the break-up of Africa is only expected in a few tens of millions of years. So you have a head start in making arrangements.