It lies about 70 kilometres (43 mi) northwest of Arequipa and is part of a north–south chain that includes the volcanoes Ampato and Sabancaya, the last of which has been historically active.

Directly north of the volcano is the Colca Valley, an important tourism destination and agricultural area[5] which has been settled since before Inca times.

[9] Canals and dams collect water flowing from the mountain and convey it to fields at Cabanaconde[10] and west of Sabancaya volcano.

[6] Other infrastructure on the mountain consists of homesteads mainly on its western flank[11] and equipment of Peru's volcano monitoring service.

The scar was formed by a gigantic landslide[5] that removed a volume of about 1.3 cubic kilometres (0.31 cu mi) from the edifice.

[29] Valleys on its outer slopes include the Mollebaya to the east, Pujro Huayjo to the southwest and Mucurca to the west.

With an area of about 630 square kilometres (240 sq mi) it is one of the largest volcanic complexes of the Central Andes.

[36] The rocks underlying the Ampato volcanic complex consist of the Sencca Formation, which is between 1.4 and 4.9 million years old.

[39] Many show evidence of neotectonic activity,[40] and some have produced earthquakes in recent times[41] or undergone aseismic creep.

[51] During December–March, the Intertropical Convergence Zone reaches the mountain[5] and draws moisture from the Amazon, as part of the South American Summer Monsoon (Pacific Ocean-derived moisture is trapped beneath a temperature inversion at an elevation of 800 metres (2,600 ft) and cannot reach Hualca Hualca).

[56] El Niño-Southern Oscillation events cause temperatures to increase and precipitation to decrease.

[57] Below an elevation of 4,500 metres (14,800 ft) there is herbaceous vegetation, dominated by Festuca and Stipa but also featuring cacti, Peruvian feather grass and other pioneer plant species.

Above that altitude, cushion plants such as Azorella compacta replace the herbs until 5,000 metres (16,000 ft) elevation, where most vegetation disappears except for lichens and mosses.

[17] Moraine tongues form complex and well-preserved structures;[5] they are particularly well-developed on the eastern flank of the volcano[7] and in the Huayuray valley, where they reach lengths of 7 kilometres (4.3 mi) and heights of 120 metres (390 ft).

[67] During the last glacial maximum, the Ampato volcanoes featured an ice cap with an area of about 347 square kilometres (134 sq mi).

[64] Final glacier retreat occurred at the beginning of the Holocene;[71] two advances in the Huayuray valley have been attributed to the Little Ice Age.

[75] Glaciers persist around the summit[17] in active cirques,[76] and there is permanent snow cover on the subsidiary peaks.

[5] It formed in several stages, with initial activity producing andesitic to dacitic-trachydacitic lava flows that build the main edifice and crop out in the collapse scar.

[17] Hydrothermal alteration and volcanic activity weakened the mountain until collapse,[21] which did not occur during an eruption but may have been triggered by an earthquake.

[20] The first collapse removed the central sector of the volcano; subsequent activity rebuilt the summit and spilled lava flows over the northeastern flank without filling in the entire scar.

[88] A few kilometres north of the summit is a group of originally three geysers; one was buried by an earthquake in 2001 and another became a hot spring.

There have been several episodes of surface uplift at Hualca Hualca linked to magma movements in the magmatic system:[97] The deformation implies magma movements on the order of 0.1 cubic kilometres (0.024 cu mi)[102] and is not strongly correlated to activity at Sabancaya.

[114] In October 2011, the inhabitants of Pinchollo organized a procession on the mountain (accompanied by Catholic ritual)[115] and offered various sacrifices.

[120] The inhabitants of Cabanaconde were sometimes compared to the misshapen mountain, with the Collaguas people calling their heads "ugly and disproportionate".

[80][128] Before the advent of the Majes canal,[129] people in Cabanaconde used to perform a regular water ritual at Hualca Hualca to begin each irrigation cycle[116] and went every year to the mountain as a community-wide ceremony to assure the continued supply of water.