Ubinas, Ticsani and Huaynaputina form a group of volcanoes that extend in north-south direction north of the chain of volcanoes that make up the rest of the Central Volcanic Zone. These volcanoes have erupted rocks with similar geochemical traits and they are located around a graben occupied by the Rio Tambo; the marginal faults of this graben are the sites of the volcanic vents and probably acted as magma conduits. The magmas erupted by all three volcanoes appear to originate in a common magma chamber at depth, with seismic activity localized along the margins of the chamber. Aside from this deep reservoir, Ubinas also has a shallower magma chamber at depth. An underground magmatic connection between Ubinas and Huaynaputina was postulated already by Antonio Vázquez de Espinosa after the 1600 eruption of the latter volcano, which was the largest historical eruption in the Andes and had an enormous impact, including causing a cold summer in the northern hemisphere.