The Awash Basin
The Awash basin extends for about 3000 km² at a height between 2500 and 2000 m a.s.l. It is delimited by several Pliocene volcanoes, the largest being the Wachacha and the Furi to the north, and the Boti and Agoïabi to the south. It is bordered to the east by the Ethiopian rift, part of the great rift system of eastern Africa. Fluvial sedimentation (pebbles, gravel, sand, and clay) was frequently interrupted by volcanic activity, whose products are important markers for stratigraphic correlations between the different archaeological sequences identified so far. Over 70 archaeological levels have been discovered so far, and more or less wide extensions of about 30 of them have been excavated.