Geologic Background:
Antuco volcano, constructed to the NE of the
Pleistocene Sierra Velluda stratovolcano, rises
dramatically above the shores of Laguna de la Laja. It
has a complicated history beginning with construction of
an andesitic stratovolcano of Pleistocene age. Edifice
failure at the beginning of the Holocene produced a large
debris avalanche that traveled down the Rio Laja to the
west. The steep-sided modern basaltic cone has grown
1,000 m since then; flank fissures and cones have also
been active.
Historic Activity:
- At least 10 eruptions since 1750, with the last in
1869. Moderate explosive eruptions were recorded in the
18th and 19th centuries from both summit and flank
vents.
- Fumarolic activity has apparently been continuous,
but of variable intensity, from the cone since the
volcano's last eruption in 1869.
- Lava flows from Antuco dammed Laja Lake's outlet in
1853, causing the water level to rise around 20 m.
Recent Activity:
- Weak summit fumaroles have been observed during
visits in 1969, 1982, and 1984.
- Fumarolic activity was visible from the small summit
scoria cone during an overflight in Feb. 1992.
Data Sources:
- Global Volcanism Network (V. 17, No. 5).
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