The volcanism of Lascar relates to the subduction of the Nazca Plate beneath the South America Plate. The Central Andes contain many hundreds of volcanoes, extending over the countries of Argentina, Bolivia, Chile and Peru. In this remote territory, where eruptions are poorly recorded, many volcanoes are higher than . They are constructed on a crust that is between thick. Volcanic centres include calderas and associated large ignimbrites, lava domes and stratovolcanoes; among the better-researched volcanoes are Galan, Nevados de Payachata, Ollague, Purico Complex, San Pedro-San Pablo, La Pacana, Tata Sabaya and Tumisa. Over 44 volcanoes in the region are considered potentially active, with a number of young volcanoes featuring fumarolic or hydrothermal activity. Guallatiri, for example, features fumarolic activity that is visible in satellite images. Also fumarolically active are: Sabancaya, El Misti, Ubinas, Tacora, Isluga, Irruputuncu, Olca, Ollague, San Pedro, Putana and Lastarria. The largest historical eruption occurred at Huaynaputina in 1600. Given the low population density around many of these volcanoes, there is often little information on their activity.