What Is The East African Rift?

Great Rift Valley, Kenya.
Great Rift Valley, Kenya.

The East African Rift (EAR) is an extensive continental rift located in East Africa. The rift has been developing for the past 20 to 25 million years, beginning in the Miocene epoch, and was previously considered to be part of the much larger Great Rift Valley. The EAR is developing into a plate boundary within the African plate, which is splitting into the Nubian Plate and the Somali Plate at a rate of 0.24 to 0.28 in each year.


The East African Rift is made up of a series of rift basins that extend for thousands of kilometers and consists of two main branches, namely the Eastern Rift Valley, which contains the Main Ethiopian Rift, and the Western Rift Valley, which contains the Albertine Rift. The EAR begins from Ethiopia’s Afar Triple Junction and extends to Mozambique through several countries, including Ethiopia, Kenya, and Uganda. The Eastern Rift Valley, which is also known as the Gregory Rift, begins in Ethiopia and extends into Kenya, where it becomes the Kenyan Rift Valley. The Western Rift Valley includes features such as Lake Malawi.

Volcanic Activity

The East African Rift contains several volcanoes, both dormant and active. Some of the prominent volcanoes include Mount Kilimanjaro, Mount Nyiragongo, Mount Longonot, Mount Kenya, and the Menengai Crater. Additionally, some volcanoes are not located exclusively within the East African Rift, but were created by the EAR and are therefore associated with it. Due to the high number of volcanoes, the EAR is the world’s most active rift system.

One of the most notable active volcanoes is DallaFilla, which is located in Ethiopia. The volcano's eruption in 2008 was the largest eruption in Ethiopia's history. Ol Doinyo Lengai, which is located in Tanzania, is the globe’s only natrocarbonatite volcano, and its lava is extremely viscous due to low quantities of silica. According to National Geographic, during an eruption, the lava can actually crystallize midair, fall, and shatter on the ground just like glass.

Crack In Southwestern Kenya

Experts have determined that the African plate is splitting. In fact, earlier this year a massive crack appeared in Kenya that caused a collapse of the Nairobi-Narok highway. The crack and collapse are linked to the ongoing splitting of the African plate, although it is an extremely slow process.

Importance In Evolution

Numerous hominid fossils have been discovered in the East African Rift, which has greatly assisted in the study of human evolution. These fossils were formed by eroded sediments that filled the valley and preserved human remains dating back millions of years. For example, notable discoveries were made by American paleoanthropologist Donald Johanson, who discovered the 3 million-year-old partial skeleton of "Lucy," a female hominin. Other remains discovered in the East African Rift include Chororapithecus abyssinicus and Nakalipithecus nakayamai.


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