Report on Nevados de Chillan (Chile) — 6 February-12 February 2019
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 6 February-12 February 2019
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2019. Report on Nevados de Chillan (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 6 February-12 February 2019. 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)
ONEMI and SERNAGEOMIN reported that during 5-12 February growth of the lava dome in Nevados de Chillán’s Nicanor Crater was very slow (0.003-0.004 cubic meters per second). White water vapor emissions, occasionally grayish from included tephra, rose as high as 1 km and drifted in multiple directions. Crater incandescence was recorded by a webcam each day. The Alert Level remained at Orange, the second highest level on a four-color scale, and residents were reminded not to approach the crater within 3 km. ONEMI maintained an Alert Level Yellow (the middle level on a three-color scale) for the communities of Pinto, Coihueco, and San Fabián.
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.