Why are many lakes in the Western Rift Valley long and deep?

Many lakes in the Western Rift Valley are long and deep because they are situated within tectonic landscapes formed by normal faults. These rift valleys are created when blocks of the Earth's crust drop down between diverging tectonic plates, resulting in deep, elongated basins.12

The formation of these lakes is directly linked to the structural development of the East African Rift System. As the crust stretches and subsides, it creates steep-walled troughs that serve as natural containers for water. For example, Lake Tanganyika is exceptionally deep—reaching 4,710 feet (1,435 meters)—due to this intense crustal movement, which creates deep, narrow depressions flanked by steep escarpments. In contrast, other lakes in the region may be shallower due to the accumulation of thick layers of sediment on the valley floor.1234