The Tarso Voon is a 3,100-metre (10,200 ft) high stratovolcano in the north of the Republic of Chad. It is located in the western center of the Tibesti Mountains. The summit of the mountain is dominated by the 14-by-18-kilometre (8.7 mi × 11.2 mi) relatively flat caldera. Extensive basaltic flows lie on the northeastern side in a 180-degree arc and are a result of the high activity in the Quaternary. In the neighborhood in northwestern direction is the Ehi Mosgau, a stratovolcano with the same elevation, 3,100 metres (10,200 ft) above sea level. Deposits from pyroclastic clouds are found 15 to 35 kilometres (9.3 to 21.7 mi) around the caldera. The mountain was constructed over a basement of Precambrian schists.