It covers an area of - of the Altiplano-Puna in Argentina, Bolivia and Chile and consists of a number of calderas, composite volcanoes and about of ignimbrite. Uturuncu lies at its centre but unlike Uturuncu most surrounding volcanic systems have been characterized by explosive eruptions, including several so-called supereruptions with volcanic explosivity indexes of 8 at Cerro Guacha, La Pacana, Pastos Grandes and Vilama. Over 50 volcanoes in the region are potentially active.