article_snippet.sent: Volcano Calbuco, in the country's south, is believed to be among the three most dangerous of Chile's 90 active volcanoes, but was not under any special observation before it suddenly sprung into life at around 6pm local time.
article_snippet.sent: Active: Volcano Calbunco is regarded as being among Chile's three most dangerous volcanoes, and is part of an active chain of around 500 that cover the south of the country .
article_snippet.sent: Not another one: southern Chile is a sparsely populated region of high volcanic activity. 
article_snippet.sent: Chile, on the Pacific 'Rim of Fire', has the second largest chain of volcanoes in the world after Indonesia, including around 500 that are potentially active.