[6] Huequi consists of a pile of lava domes that are heavily eroded and cut by sector collapses.

[7] Debris avalanches, partly channelled by a northwestward trending valley in the edifice, have formed a fan on that side of Huequi.

[14] The volcanic rocks define a calc-alkaline suite[15] that resembles the adakites of Nevado de Longavi.

[18] The region has a humid climate, with storm systems from the Pacific Ocean bringing about 2 m (79 in)[12] or 3–3.2 m (120–130 in)[5] of precipitation during autumn and winter.

[12] It is covered by the Valdivian rainforest, with Amomyrtus meli, Drimys winteri, Luma apiculata, Nothofagus nitida and Podocarpus as representative plant species.

[10] During the Holocene, the volcano repeatedly produced lava domes that frequently collapsed, and explosive eruptions that deposited tephra.

The collapses were not energetic, with most of the debris being confined by the surrounding topography; their heavy vegetation cover indicates that they are older than the most recent eruption.

[23] These eruptions reached a volcanic explosivity index of 2–3[24] and deposited patches of tephra to the north of the volcano.

[28] The Porcelana geysers have produced pinnacles of travertine reaching heights of 2.5 metres (8 ft 2 in); this extreme size in a highly erosive environment may be due to microbial chemical processes.