Planchón-Peteroa Volcano | John Seach



35.24 S, 70.57 W
summit elevation 4107 m

Planchón-Peteroa Volcano is located in central Chile-Argentina border. The volcano contains several overlapping calderas.

Planchon Volcano
Planchon is the northernmost basalt containing volcano of the Southern Volcanic Zone. The volcano contains about 25 cubic km of basalt and basaltic andesite lavas. Planchón does not contain any silicic dikes or plugs. The growth of the volcano was not interrupted by glaciation, and growth of the volcano was rapid enough to prevent deep erosion during its development.

Part of Planchón collapsed 11,000 years ago producing Río Teno debris avalanche, which traveled 95 km. Peteroa contains a small steaming crater lake.

Peteroa Volcano
Volcan Peteroa is the youngest volcano of the complex, has erupted mixed magmas of andesitic and dacitic composition. Lavas from currently active Peteroa volcano are
andesites formed by magma mixing. Peteroa volcano consists of several scattered vents between Azufre and Planchon. It is not an independent volcano and has less than one cubic kilometer of preserved lavas and pyroclastic deposits. At least four
Peteroa mafic andesite flows erupted from a vent located near Azufre crater.

Within the amphitheater of peteroa there are two phreatomagmatic explosion pits (100 m diameter, 70 m depth) and a possible third explosion pit, suggested by a 100 m diameter spiral crevasse in ice. The volcano has a history of explosive eruptions.

Peteroa andesite and dacite lavas were formed by magma mixing, indicating that the volcanic system has evolved over the past 500,000 years from bimodal basalt-dacite (Azufre) and basaltic (Planchon) to mixed andesite lavas (Peteroa).

2010 Eruption
Continuous ash emissions were reported from Planchón-Peteroa Volcano on 13th January 2010. Ash reached a height of 25,000 ft.

2006 Fumarolic Activity
Intense fumarolic activity only occurred at Planchón-Peteroa volcano around 25th January 2006.

1998 Eruption
In November 1998 small phreatic eruptions were reported at the volcano, and ash fell on Carrizales, 8 km NW.

1991 Eruption
On 9th February 1991 an eruption occurred at Planchon-Peteroa Volcano. The eruption column reached a maximum height of 1000 m near the volcano. Fish were killed in the Claro and Teno rivers. Ashfall was reported 30 km ESE of the volcano.

1937 Eruption
An eruption in 1937vproduced a small pyroclastic cone and lava flow contained entirely within the summit amphitheater.

Further reading
Lamberti, María Clara, et al. "Soil CO2 flux baseline in Planchón–Peteroa Volcanic Complex, Southern Andes, Argentina-Chile." Journal of South American Earth Sciences 105 (2021): 102930.

Tormey, D.R., et al., 1995. Geochemistry of the active Azufre—Planchon—Peteroa volcanic complex, Chile (35 15' S): evidence for multiple sources and processes in a cordilleran arc magmatic system. Journal of Petrology, 36(2), pp.265-298.

Planchón-Peteroa Volcano Eruptions

2010, 1998, 1991, 1967, 1962, 1960, 1959, 1938, 1937, 1889-94?, 1878, 1872?, 1869?, 1860, 1842?, 1837, 1835, 1762, 1660