Callaqui

Geography & Climate

Callaqui is located in Chile, within the Southern Andean Volcanic Arc of the broader South America Volcanic Regions. Situated at 37.92° S, 71.45° W in the Southern Hemisphere, the volcano lies within a temperate climate zone. At 3,164 meters above sea level, Callaqui rises above the surrounding terrain into montane or subalpine conditions. The elevation creates distinct ecological zones along its flanks, from forested lower slopes to exposed rocky terrain near the summit. 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

Callaqui 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 Callaqui, 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 andesite / basaltic andesite, 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

Callaqui has 6 recorded eruptions in the geological database, spanning from 1751 CE to 2012 CE. The most powerful recorded event was an explosive event producing ash plumes up to several kilometers in 1751 CE, reaching VEI 2 on the Volcanic Explosivity Index. This eruption frequency indicates a moderately active volcanic system with periodic reawakenings. With eruptive activity as recently as 2012 CE, Callaqui remains an actively monitored volcano.

Significance

With 6 recorded eruptions on file, Callaqui has enough documented activity to help scientists identify patterns in its eruptive behavior. Given its recent activity, Callaqui is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

The late-Pleistocene to Holocene Callaqui stratovolcano has a profile of an overturned canoe, due to its construction along an 11-km-long, SW-NE fissure above a 1.2-0.3 million year old Pleistocene edifice. The ice-capped, basaltic andesite volcano contains well-preserved cones and lava flows, which have traveled up to 14 km. Small craters 100-500 m in diameter are primarily found along a fissure extending down the SW flank. Intense solfataric activity occurs at the southern portion of the summit; in 1966 and 1978, red glow was observed in fumarolic areas (Moreno 1985, pers. comm.). Periods of intense fumarolic activity have dominated; few historical eruptions are known. An explosive eruption was reported in 1751, there were uncertain accounts of eruptions in 1864 and 1937, and a small phreatic ash emission was noted in 1980.

— Smithsonian Institution, Global Volcanism Program