Antillanca Volcanic Complex

Geography & Climate

Antillanca Volcanic Complex is located in Chile, within the Southern Andean Volcanic Arc of the broader South America Volcanic Regions. Situated at 40.78° S, 72.15° W in the Southern Hemisphere, the volcano lies within a temperate climate zone. With a summit elevation of 1,979 meters above sea level, Antillanca Volcanic Complex is a moderately sized peak that remains accessible to hikers and researchers for much of the year. The volcanic landform is characterized as a composite, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

Antillanca Volcanic Complex sits in a subduction zone, where one tectonic plate dives beneath another, creating intense heat and pressure that generates magma. Subduction zones are responsible for many of the world's most explosive volcanoes and deadliest eruptions. For communities in Chile near Antillanca Volcanic Complex, this tectonic setting means the volcano is capable of producing powerful explosive eruptions, pyroclastic flows, and lahars that can threaten populated areas within tens of kilometers of the summit. The dominant rock type is basalt / picro-basalt, a dark, fine-grained volcanic rock that forms from rapidly cooling, low-viscosity lava. Basaltic eruptions tend to be less explosive and produce fluid lava flows that can travel long distances. While less immediately dangerous than explosive eruptions, basaltic lava flows can destroy structures and infrastructure in their path, and volcanic gases released during these eruptions can affect air quality over a wide area.

Eruption History Summary

Antillanca Volcanic Complex has 2 recorded eruptions in the geological database, spanning from 960 BCE to 230 BCE. The most powerful recorded event was a paroxysmal eruption with devastating regional consequences in 230 BCE, reaching VEI 5 on the Volcanic Explosivity Index. Notable eruptions include 230 BCE (VEI 5), 960 BCE (VEI 5). These eruptions span roughly 730 years of volcanic history.

Significance

With a maximum recorded VEI of 5, Antillanca Volcanic Complex has demonstrated the capacity for paroxysmal eruptions comparable to the 1980 eruption of Mount St. Helens. Eruptions of this scale can devastate areas within 20-30 kilometers and produce ash fall that disrupts aviation and agriculture across hundreds of kilometers.

GVP Reference Summary

The Antillanca Volcanic Complex is a cluster of late-Pleistocene to Holocene basaltic-to-andesitic scoria cones, maars, and small stratovolcanoes covering an area of 380 km2 SE of Lago Puyehue and NE of Lago Rupanco. The most prominent edifice is the Holocene Casablanca stratovolcano, which has a truncated conical profile and produced major explosive eruptions about 2,910 and 2,260 radiocarbon years ago. Older late-Pleistocene stratovolcanoes, such as Sarnoso to the SW and Fiuchá to the NW, are extensively dissected by glaciers. Fissures oriented in four major directions influence the orientation of the cones. Thermal areas are found in scattered locations on the NW side of the complex.

— Smithsonian Institution, Global Volcanism Program