Fantale is a stratovolcano on the floor of the Ethiopian Rift Valley. Steam issues from vents along the inner walls of the volcano's 6 km (4 miles) wide caldera.
Small cones and craters fed by the same magma chamber as Fantale occur around the volcano. Fantale has no documented activity other than the small fumaroles, but local tribal stories suggest that the small nearby volcano Sabober erupted in about 1820.
Fantale is surrounded by a broad apron of welded tuff called ignimbrites. These ignimbrites are famous for the blisters that break the surface. Apparently the ignimbrite flowed over a lake and the flow's heat caused lake water to flash to steam which domed up the ignimbrite. Many of the blisters are intact but others have collapsed, forming small caves that animals and people have occasionally lived in.
Sources of Information:
Richard JJ, Neumann van Padang M. 1957, Africa and the Red Sea. Catalog of Active Volcanoes of the World, Rome IAVCEI 4.p27-29