The Tanganyika Rift Fault system bounds Lake Tanganyika, the enormous linear lake that forms the heart of the western branch of the East African Rift between the Democratic Republic of the Congo and Tanzania. A series of alternating border faults on either side of the lake control its extraordinary depth and 670-kilometre length.
These normal faults accommodate the slow east-west stretching of the African continent, dropping the rift floor to more than 1,400 metres below the lake surface and making Tanganyika the second-deepest lake on Earth. The faults alternate from one shore to the other along the rift, producing a chain of tilted half-graben basins.
The region is seismically active, with frequent moderate earthquakes and occasional larger events such as the magnitude ~6.8 Kalemie earthquake of 2005 beneath the lake. This activity confirms that the border faults are still growing, deepening the basin and driving the ongoing rupture of the continent.