The Rift Valley in East Africa is a huge geological fault in the earth's crust. Passes through Northern Ethiopia to the central part of Mozambique. The rift valley begins in the Ethiopian highlands and stretches along the meridian for thousands of kilometers, dividing into branches (the total length is more than 9000 km). The width is up to 200 kilometers, and the depth of this huge fault varies from a few hundred meters to a kilometer.
Research history
The Great African Rift Valley was first discovered in the late 19th century. It can now be clearly seen from space.
It got its name from the English geologist John W alter Gregory, who studied East Africa and Australia. Fossilized remains of hominids (a family of the most advanced primates, including humans) were found in these places.
Geology
The Rift Valley was formed in the Oligocene-Quaternary time as a result of a series of shifts in the earth's crust accompanied by intensevolcanic activity due to the displacement of the lithospheric plates (African and Arabian). It consists of two branches, the eastern one (Gregory's Rift) stretches north from Lake Victoria and goes to the Red Sea depression.
On the way it passes through Tanzania and Kenya. The second western branch is shorter, the Albertine Rift. The northern part of the fault turned into the Red Sea, filled with water, every year this depression gradually moves apart due to the continuous formation of oceanic crust.
What is a rift?
The rift valley can best be called the East African rift system. A rift is a huge elongated depression in the earth's crust that occurs at the point of rupture of the earth's crust when it is subjected to tensile forces or longitudinal displacement of two plates. Such a fissure can form on land and in the ocean. There are areas in the rift system where oceanic crust can form. An example of this phenomenon in the Great Rift Valley is the Afar Basin, located in its northern part.
Afar Valley
This is a deep depression that has sunk to 150 meters below sea level as a result of geological processes. This piece of land is also called the "Afar Triangle", since the intercontinental rifts of the Gulf of Aden and the Red Sea articulate with the system of continental East African rifts. The relief and climate contributed to the creation of one of the hottest places on the planet. The average minimum temperature is + 25 degrees, and the maximum is +35, the annual rainfall is 200 millimeters. The Afar depression is about two million years old, it was formed in the Quaternary period. Volcanoes rise along the Afar border, some of them active.
Dabbahu Volcano has a height of 1442 meters, it is known for its eruption in 2005. Before the awakening of the volcano, earthquakes occurred, as a result of which a large crack formed in the earth's crust. It is called the Dabbahu Fault. Scientists believe that this very fault precedes the beginning of the separation of the Somali plate from the African one. Thus, Africa will be divided in two in the future. The Afar Valley is the second place, after Ireland, where you can study the oceanic crust directly on land.
Another depression is also famous for its volcano - Erta Ape. It is a shield volcano that has been continuously active since 1976 and is the only one on the planet with two lava lakes.
Volcanoes of the Great Rift Valley
In the eastern branch of the valley is the highest volcano in Africa - Kilimanjaro, which is at the same time the highest point of the mainland. It is potentially active, gas emissions are observed and it is believed that the cone could collapse, leading to a very large eruption. At the main peak of Kilimanjaro, magma is very close to the surface.
The Ngorongoro volcanic caldera arose after the destruction of a huge volcano 2.5 million years ago. The diameter of its crater ranges from 17 to 21 kilometers. Its depth is 610 meters, the total area is 265 square kilometers. ATThere are many other volcanoes in the Great Rift Valley, the highest being Elgon, Kilimanjaro and Kenya. Even the National Park dedicated to volcanoes has been created; it is located in the northwestern part of Rwanda. There are volcanoes Sabinho, Gahinga, Mukhabura, Bisoke, Karisimbi.
Great Lakes of Africa
The Rift Valley passes through the lakes of Africa, among them there are large ones - Victoria, Nyasa, Tanganyika. And smaller bodies of water.
Southwest of the Afar depression in the rift zone, a whole chain of lakes has formed: Abaya, Zvay, Shala, Chamo.
Lake Rudolph was formed at the place of the earth's crust trough between the Kenyan and Ethiopian arches. Here is the rift Rudolph of the same name with the lake.
Tanganyika is the world's longest fresh water lake. Its length is 700 kilometers. It belongs to the western branch of the rift valley, as well as lakes - Albert, Kivu, Rukva, Eduard.
Lake Victoria is the largest in Africa and the second largest freshwater lake after the Upper (in North America) on the planet.
Nyasa. In the area of this lake, the eastern and western branches of the Great Rift Valley join and go to the Indian Ocean.
