Osorno Volcano | John Seach



41.10 S, 72.49 W
summit elevation 2652 m

Osorno Volcano is located in southern Chile. Osorno is one of the most active volcanoes in southern Chile. Historical eruptions have produced lava flows that have entered both Llanquihué and Todos los Santos lakes.

osorno volcano
Osorno Volcano - John Seach

Geology of Osorno volcano
The volcano is exclusively basaltic except for two small dacitic domes in the most recent volcanic unit.

Charles Darwin, the great naturalist remarked about Osorno "the volcano of Osorno stood out in bold relief; and it was curious to watch, as the sun rose, the outline gradually fading away in the glare of the eastern sky."

Osorno volcano is best observed in the early morning or late evening when it stands out against a darker background.

1835 Eruption
A Strombolian eruption occurred at Osorno volcano in 1835 and was witnessed by Charles Darwin.

‘On the night of 19th the volcano of Osorno was in activity. At midnight the sentry observed something like a large star, from which state the bright spot gradually increased in size till about three o'clock, when a magnificent spectacle was presented. By the aid o a glass, dark objects in constant succession were seen, in the midst of a great red glare of light, to be thrown upwards and to fall down again. The light was sufficient to cast on the water a long bright reflection. By the morning the volcano has resumed its tranquility’.

The 1835 eruption of Osorno occurred on the SW flank of the volcano, and produced several pyroclastic cones and three fissures.

Further reading
Díaz, D., Zúñiga, F. and Castruccio, A., 2020. The interaction between active crustal faults and volcanism: A case study of the Liquiñe-Ofqui Fault Zone and Osorno volcano, southern Andes, using magnetotellurics. Journal of Volcanology and Geothermal Research, 393, p.106806.

Lara, L.E., Orozco, G. and Piña-Gauthier, M., 2012. The 1835 AD fissure eruption at Osorno volcano, Southern Andes: Tectonic control by the intraarc stress field instead of remote megathrust-related dynamic strain. Tectonophysics, 530, pp.102-110.

Lopez-Escobar, L., Parada, M.A., Moreno, H., Frey, F.A. and Hickey-Vargas, R.L., 1992. A contribution to the petrogenesis of Osomo and Calbuco volcanoes, Southern Andes (41° 00'-41° 30'S): comparative study. Andean Geology, 19(2), pp.211-226.

Osorno Volcano Eruptions

1869, 1855, 1851, 1837, 1834-35, 1790-91, 1765, 1719, 1644?, 1640?, 1575?, 1310