Afar triple junction

This area is considered a present-day example of continental rifting leading to seafloor spreading and producing an oceanic basin.

[1] The third rifting arm runs south extending around 4,000 kilometres (2,500 mi) through the countries of Kenya, Uganda, the Democratic Republic of Congo, Rwanda, Burundi, Tanzania, Zambia, Malawi and, finally, Mozambique.

At the same time as the subduction in the north, there was mantle upwelling causing the crust to down warp and swell into domes throughout the East African Rift System.

[2] Baker et al. (1972) also suggest that the uplift of this area is sporadic and divided by long periods of stability and erosion.

It has been argued that the current Ethiopian plateau is a result of the most recent uplift of 500 metres (1,600 ft) estimated to be an Oligocene–early Miocene event.

The uplift caused by the Ethiopian dome resulted in a massive faulting area of 1,000 metres (3,300 ft) in the Afar region.

According to McKenzie and Morgan's 1969 classification, the Afar triple junction is of ridge-ridge-ridge (RRR) type, describing the movement of the three plates with respect to each other.

Following Mackenzie and Morgan's stability model, RRR geometry will continue stably through time until there is a change in the tectonic movement.

This uplift caused massive crustal extension leading to horst and graben structures associated with normal, extensional, faults.

The uplift ended in collapse around 25 Mya into the Afar depression covering more than 200,000 km2 (77,000 sq mi) and spreading at a rate of 6 to 17 millimetres per year (0.24 to 0.67 in/year).

Grand et al. (1997) model the large anomaly to extend from the base of the mantle to approximately 1,000 kilometres (620 mi) depth.

These faults have been documented by Chorowicz (2005) and aid in further verification of the future of this region and the potential for continued extension and subsidence.

There is also the possibility of a subduction zone forming along the eastern side of the Somali plate, caused by the spreading of the EARS and the Mid-Indian Oceanic ridge.

If current tectonics continue without change it is thought that an ocean basin with a mid-oceanic ridge will eventually separate the Nubian, Somali and Arabian plates.