Report on Calbuco (Chile) — 27 May-2 June 2015
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 27 May-2 June 2015
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2015. Report on Calbuco (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 27 May-2 June 2015. Smithsonian Institution and US Geological Survey.
41.33°S, 72.618°W; summit elev. 1974 m
All times are local (unless otherwise noted)
On 27 May OVDAS-SERNAGEOMIN reported that seismicity at Calbuco fluctuated at low levels and continued to decline. According to ONEMI, the 10-km evacuation zone remained in effect, with controlled access to some communities allowed for part of the day; about 500 people remained displaced. On 28 May OVDAS-SERNAGEOMIN lowered the Alert Level to Yellow (the second lowest level on a four-color scale).
Geologic Background. Calbuco is one of the most active volcanoes of the southern Chilean Andes, along with its neighbor, Osorno. The late-Pleistocene to Holocene andesitic volcano is immediately SE of Lake Llanquihué in the Chilean lake district. Guanahuca, Guenauca, Huanauca, and Huanaque, all listed as synonyms of Calbuco (Catalog of Active Volcanoes of the World), are actually synonyms of nearby Osorno volcano (Moreno 1985, pers. comm.). The edifice is elongated in a SW-NE direction and is capped by a 400-500 m wide summit crater. The complex evolution included collapse of an intermediate edifice during the late Pleistocene that produced a 3-km3 debris avalanche that reached the lake. It has erupted frequently during the Holocene, and one of the largest historical eruptions in southern Chile took place from Calbuco in 1893-1894 that concluded with lava dome emplacement. Subsequent eruptions have enlarged the lava-dome complex in the summit crater.