Thursday, July 15, 2010

Tungurahua is an active 5,023m-high andesitic-dacitic stratovolcano which lies in the Andes Central Range of Ecuador. Towering more than 3 km above its northern base, this steep-sided mountain is one of Ecuador's most active volcanoes, giving its name to the province of Tungurahua. Volcanic activity restarted in 1999 and is still going on as of 2010 with major eruptions on August 16, 2006, 6 February 2008, and 28 May 2010. Tungurahua is Quichua word which means "Throat of Fire."

Three major volcanic edifices have been sequentially built up since the mid-Pleistocene over a basement of metamorphic rocks. Tungurahua II was built within the past 14,000 years following the collapse of the initial edifice. Tungurahua II itself collapsed about 3000 years ago and produced a large debris-avalanche deposit and a horseshoe-shaped caldera open to the west, inside which the modern glacier-capped stratovolcano, Tungurahua III, was constructed. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. Prior to a long-term eruption beginning in 1999 that caused the temporary evacuation of the city of BaƱos at the foot of the volcano, the last major eruption had occurred from 1916 to 1918, although minor activity continued until 1925.