Puyehue Volcano Eruption, Andes, Chile

• 1960–2011 period
Following the end of the 1960 eruption, Cordón Caulle has remained relatively quiet if compared with the first half of the 20th century. On March 2, 1972 there was a report of an eruption west of Bariloche in Argentina. The Chilean emergency office ONEMI (Oficina Nacional de Emergencia del Ministerio del Interior) organized a flight over the area with two volcanologists aboard. Puyehue and Cordón Caulle as well the Carrán crater were found without activity. From accounts of local inhabitants of the area it is inferred that a small pumice cone was formed around 1990. In 1994 a temporarily emplaced seismic network registered tremors north of Puyehue's cone which reached IV and V degrees on the Mercalli intensity scale. This prompted ONEMI to invoke an emergency action committee, however soon afterward unrest ceased. Between May 4 and 17 of 2011 seismic activity partly attributed to the movements of fluids was detected Southern Andean Volcano Observatory (OVDAS). The activity concentrated around and in Cordillera Nevada caldera and on western Cordón Caulle. This prompted SERNAGEOMIN-OVDAS to declare yellow alert.
• 2011 eruption
A new eruption started on June 4, 2011. As of 4 June, 3,500 people were evacuated in nearby areas, while the ash cloud reached the city of Bariloche, in Argentina, where the local airport was closed. At approximately 16:30 PM local time, Neuquén's Airport further East in Argentina was also closed due to the ash cloud.