Tullu Moje

The Bora-Bericha-Tullu Moye (BBTM) volcanic complex includes three main silicic edifices and at least 11 smaller cones within the Main Ethiopian Rift. Tullu Moye is a youthful trachytic-to-rhyolitic pumice cone with a 700-m-wide summit crater. A large silicic lava flow at Giano was erupted about two centuries ago from a regional fissure. Flank fissures have produced silicic lava flows as recently as about 1900 CE. Many large lava flows can be seen N of the Tulle Moye cone, extending for about 20 km in an arc between Gedamsa and the Bericha cone to the SE shore of Koka Lake. The silicic Bora and Bericha pumice cones are SE of Koka Lake. Bora has a 1.5-km-wide summit crater; the more conical Bericha is capped by a small summit crater and has a 1-km-wide crater on its S flank. Small silicic pyroclastic cones are found on the E flanks of both. All volcanic products in this area are considered to be Holocene, and there is ongoing fumarolic activity.