Which plate boundary created the East African Rift?

The plate boundary creating the East African Rift is a divergent boundary.

A divergent boundary forms where tectonic plates move apart. In East Africa, the African Plate is gradually separating into the Nubian Plate to the west and the Somali Plate to the east. Stretching thins and fractures continental crust, producing rift valleys, earthquakes and volcanism.

The East African Rift system extends for thousands of kilometres from the Afar region toward southeastern Africa. In the Afar Depression, the African, Somali and Arabian plates meet at a triple junction, making the region especially active.

The rift has not yet become a fully developed ocean basin along its entire length. If extension continues, the continental crust could eventually split farther and allow new oceanic crust to form. This differs from a transform boundary, where plates mainly slide sideways.