Scientists have found the "Rosetta Stone" of supervolcanoes, those giant pockmarks in the Earth's surface produced by rare and massive explosive eruptions that rank among nature's most violent events. The eruptions produce devastation on a regional scale — and possibly trigger climatic and environmental effects at a global scale.

Late Sunday yesterday Mt. Redoubt began eruption in Southern Alaska report the U.S. Geological Survey and Alaska Volcano Observatory.

The Chaiten volcano now erupting in southern Chile is one of 200 to 300 volcanoes in the "Andean Arc" region of Chile, Peru, Ecuador and Columbia considered active by volcanologists, some of which lie in much more densely populated areas, said a University of Colorado at Boulder geologist who has studied Chaiten.

A volcano on Indonesia's Sulawesi island has erupted, sending ash raining down on at least one village and spewing smoke about 1,500 metres into the air, an official said.