Photo By: Hugo Moreno (University of Chile)

Calbuco Volcano, Chile

Calbuco is a composite, continental volcano in southern Chile, located southeast of Llanquihue Lake and northwest of Chapo Lake, in the Los Lagos Region. Along with its neighbor, Osorno, Calbuco is one of the most active volcanoes of the southern Chilean Andes. The volcano and its surrounding area are protected within Llanquihue National Reserve. It is an extremely explosive andesitic volcano that underwent edifice collapse in the late Pleistocene, producing a volcanic debris avalanche that reached the lake. Standing nearly 2003 meters tall, the volcano is topped with a 400-500 meter wide summit crater.

Elevation: 2003 meters (6572 ft.)
Location: Southern Chile
Range: Andes
Volcanic Arc/Belt: South Volcanic Zone
Age of Rock: Pleistocene
Last Eruption: 1972
Plate Boundary: Subduction boundary
Tectonic Plates: Nazca subducting underneath South American
Type of magma: basaltic
Nearby cities: Puerto Varas and Puerto Montt
Attractions: incredible relief, springs

Volcanic Shape
The Calbuco Volcano reaches an altitude of 6,610 feet above sea level, and it’s about 4,921 feet above the level of the local peaks. Due to its altitude and extensive mass, the volcano dominates entirely the panoramic view in the nearby areas of Puerto Montt. Its summit region is composed by a platform close to 4,921 feet of extension covered by ice and snow. The highest point, its southern peak, is known as “The Pyramid”, due to its triangular shape formed by group of rocks. Its structure presents marked features of erosion.

Volcanic Eruptions at Calbuco

Calbuco has had at least 9 eruptions since1837, with the latest one in 1972. One of the most historical eruptions in southern Chile took place there in 1893-1894. Violent eruptions ejected 30-cm bombs (the largest piece of pyroclastic material) to distances of up to 8 km from the crater, accompanied by voluminous hot lahars. Strong explosions occured in April 1917, and a lava dome formed in the crater, accompanied by hot lahars. Another short explosive eruption in January 1929 also included an apparent pyroclasic flow and a lava flow. The last major eruption of Calbuco, in 1961, sent ash columns 12-15 km high and produced plumes that dispersed mainly to the southeast and 2 lava flows were also emitted. There was a minor, 4-hour eruption on August 26, 1972. Strong fumarolic emission from the main crater was observed on August 12, 1996.

Environmental Effects
Along with most other volcanoes, Calbuco helps contribute to ozone depletion, as well as both cooling and warming of the earth's atmosphere. Volcanic eruptions can enhance global warming by adding carbon dioxide and water vapor, both greenhouse gases, to the atmosphere. However, a far greater amount of CO2 is contributed to the atmosphere by human activities each year than by volcanic eruptions. Volcanoes also contribute to the haze effect. Suspended particles, such as dust and ash (emitted from the volcano) can block out the earth's sunlight, thus reducing solar radiation and lowering average global tempuratures. In general, with usually explosive central vent eruptions, the pyroclastic flows, lava flows, and lahars have caused cities great devestation to its surrounding area. The main reason many farmers decide to live near to a volcano is the rich volcanic soil. Volcanic deposits can develop into some of the richest agricultural lands on earth.

Photo by: John Seach

Bibliographies:
"Calbuco." Global Volcanism Program. Smithsonian Institutions. 23 Mar. 2009 http://www.volcano.si.edu/world/volcano.cfm?vnum=1508-02=.
"Calbuco Volcano." The Smithsonian/NASA Astrophysics Data System. 23 Mar. 2009 http://adsabs.harvard.edu/abs/1995CoMP..119..345L.
Ritchie, David, and Alexander E. Gates, PH.D. "Calbuco." Encyclopedia of Earthquakes and Volcanoes. 2001.
Seach, John. "Calico Volcano." Volcano Live. 23 Mar. 2009 http://www.volcanolive.com/calbuco.html.