Bora-Bericha-Tullu Moye

Geography & Climate

Bora-Bericha-Tullu Moye is located in Ethiopia, within the Main Ethiopian Rift Volcanic Province of the broader Eastern Africa Volcanic Regions. Situated at 8.21° N, 39.08° E in the Northern Hemisphere, the volcano lies within a tropical climate zone. At 2,345 meters above sea level, Bora-Bericha-Tullu Moye rises above the surrounding terrain into montane or subalpine conditions. The elevation creates distinct ecological zones along its flanks, from forested lower slopes to exposed rocky terrain near the summit. The volcanic landform is characterized as a cluster, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

Bora-Bericha-Tullu Moye is situated along a rift zone, where tectonic plates are pulling apart. As the crust thins and fractures, magma rises to fill the gap, creating volcanic activity. Rift volcanism typically produces more fluid lava flows rather than explosive blasts, which means communities near Bora-Bericha-Tullu Moye in Ethiopia generally face slower-moving hazards like lava flows and ground fissures rather than sudden pyroclastic events. However, rift volcanoes can still generate significant ash emissions and gas releases that affect local air quality. The dominant rock type is rhyolite, a silica-rich volcanic rock associated with highly viscous magma. Rhyolitic eruptions can be extremely explosive and are responsible for some of the largest volcanic events in Earth's history, including supervolcanic caldera-forming eruptions. The high silica content traps dissolved gases, building enormous pressure that can lead to catastrophic explosive releases.

Eruption History Summary

Bora-Bericha-Tullu Moye has 3 recorded eruptions in the geological database, spanning from 760 CE to 1900 CE. The most powerful recorded event was a gentle, effusive event in 1900 CE, reaching VEI 1 on the Volcanic Explosivity Index. These eruptions span roughly 1,140 years of volcanic history. The most recent eruption in 1900 CE places this volcano within the modern era of volcanological observation.

GVP Reference Summary

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.

— Smithsonian Institution, Global Volcanism Program