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Report on Nevados de Chillan (Chile) — 22 March-28 March 2017

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 22 March-28 March 2017
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2017. Report on Nevados de Chillan (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 22 March-28 March 2017. Smithsonian Institution and US Geological Survey.

Volcano Profile |  Weekly Report (22 March-28 March 2017)


Nevados de Chillan

Chile

36.868°S, 71.378°W; summit elev. 3180 m

All times are local (unless otherwise noted)


On 24 March OVDAS-SERNAGEOMIN reported that during an overflight of Nevados de Chillán scientists observed a single 100-m-diameter crater, the result of two active craters merging together sometime between 7 and 15 March. In addition there were five explosions in the period of about an hour, ejecting tephra 900 m high which dispersed SE. The pattern of activity changed on 17 March with increased frequency and magnitude of the explosions. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 3-km radius.

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.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)