A geological phenomenon is dividing the African continent in two, at the level of the Great Rift Valley which crosses the countries of South-East Africa. Scientists have been waiting for years, but recent events suggest that things are accelerating.
The torrential rains falling down since March 16 in Kenya are of rare violence. They have already killed at least 16 people in the floods and landslides they caused. They have also caused major road collapses in the country. The busy May Mahiu-Narok road, located in the south of the country, a few kilometers from the capital Nairobi, has been the most damaged. Under the eyes of stunned motorists, an impressive rift 15 m deep and 20 m wide was created swallowing all the muddy water. Around this road, the fertile plains and arable lands have suddenly appeared cracked as well.
This region is located in the Great Rift Valley, which crosses the continent from the Horn of Africa to Mozambique. The area has been considerably weakened for years. It has suffered many earthquakes and landslides due to a powerful geological activity long known to geologists.
“Scientists have known for many years that the African tectonic plate separates from the Somali plate at the level of the Great Rift Valley, a geological phenomenon that extends from the Red Sea to the Zambezi River over more than 6,000 km, and which is also 60 km wide, “confirms David Adede, a geologist quoted by the British newspaper, The Independent.
Four countries in the Horn of Africa — Somalia, half of Ethiopia, Kenya and Tanzania — are expected to separate from Africa to form a new continent in around 50 million years. A new ocean will appear and separate the two shores. In any case, this is what geologists have always expected.
In September 2005, a giant fissure had already opened up in the earth’s crust north of Afar, a desert area some 100 kilometers south of the Ethiopian-Eritrean border. It stretches for about 60 km long, between 2 and 12 km deep and about 5 meters wide.
This gigantic crack occurred at the same time as a series of earthquakes and an eruption on the side of Dabbahu, a volcano that rises to 1,442 m. Since then, a dozen other smaller cracks have opened in the south. “This opening episode of autumn 2005 probably marks the moment of the opening of an ocean in this part of the world,” said Eric Jacques, deputy director of the Institute of Earth Physics in Paris ( IPGP), interviewed by Le Figaro in 2009.
According to this physicist, “in a million years, the Afar depression will have opened an additional 30 km”, but he acknowledges that “we do not yet know all the underground plumbing” of this region of the world, whose political instability does not help geologists to work long on the spot. Hence the difficulty to project and warn local populations of a possible danger.
“In the recent past, the Rift Valley may have remained tectonically inactive,” said David Adede in The Independent. But there could be deep movements in the earth’s crust that have given rise to areas of weakness that extend to the surface. These areas of weakness form lines of faults and fissures that are normally filled with volcanic ash, probably from nearby Mount Longonot. The rains only aggravated the situation by washing the ashes, which eventually exposed the cracks. “