Report on Nevados de Chillan (Chile) — 10 June-16 June 2020
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 June-16 June 2020
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2020. Report on Nevados de Chillan (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 10 June-16 June 2020. Smithsonian Institution and US Geological Survey.
Nevados de Chillan
36.868°S, 71.378°W; summit elev. 3180 m
All times are local (unless otherwise noted)
SERNAGEOMIN reported that a body of lava in Nevados de Chillán’s Nicanor Crater was visible in 11 June satellite images. The structure was oriented in the NNW direction and was about 100 m long and 60 m wide. Adjacent to the lava body was a smaller structure, oriented N. The sulfur dioxide emission rate was 300 tons/day on 14 June, which was an average rate. A thermal anomaly was visible on 10 and 14 June, and at night incandescent material was sometimes ejected from the crater. The Alert Level remained at Yellow, the second lowest level on a four-color scale, and residents were reminded not to approach the crater within 3 km. ONEMI stated that the Alert Level Yellow (the middle level on a three-color scale) remained in place for the communities of Pinto and Coihueco, and that the public should stay at least 2 km away from the crater.
Geologic Background. The compound volcano of Nevados de Chillán is one of the most active of the Central Andes. Three late-Pleistocene to Holocene stratovolcanoes were constructed along a NNW-SSE line within three nested Pleistocene calderas, which produced ignimbrite sheets extending more than 100 km into the Central Depression of Chile. The largest stratovolcano, dominantly andesitic, Cerro Blanco (Volcán Nevado), is located at the NW end of the group. Volcán Viejo (Volcán Chillán), which was the main active vent during the 17th-19th centuries, occupies the SE end. The new Volcán Nuevo lava-dome complex formed between 1906 and 1945 between the two volcanoes and grew to exceed Volcán Viejo in elevation. The Volcán Arrau dome complex was constructed SE of Volcán Nuevo between 1973 and 1986 and eventually exceeded its height.