Ash and steam erupti from the Puyehue-Cordon Caulle volcanic chain near Osorno city, Chile, on June 5, 2011. (Reuters/Air Force of Chile/Handout)

Ash and steam erupti from the Puyehue-Cordon Caulle volcanic chain near Osorno city, Chile, on June 5, 2011. (Reuters/Air Force of Chile/Handout)