Incahuasi Central Volcanic Zone of the Andes together with about 110 other Quaternary volcanoes, and lies in the southern sector of the volcanic zone; other volcanic zones in the Andes are the Northern Volcanic Zone, the Southern Volcanic Zone and the Austral Volcanic Zone. The history of volcanic activity is poorly known for most of these volcanoes owing to the lack of dating; only a few historical eruptions have been recorded, such as an eruption at Ojos del Salado in 1993. Incahuasi is located northeast of Ojos del Salado, the highest volcano in the world. Both volcanoes are found at the
Ojos del Salado of the Nazca Plate beneath the South America Plate became increasingly shallower and this caused volcanism to shift from the Maricunga Belt to the Ojos del Salado region. The Paleozoic basement crops out only northwest of Nevado Tres Cruces. Other geologic units in the region are Oligocene sedimentary units and volcanic rocks ranging from Oligocene age to less than 1.5 million years old. The area is part of a tectonic boundary between a volcanically active region north of the boundary and a less volcanically active region south of the boundary, which is also characterized by geographical differences, e.g. the presence