SfondoThe steep-sided andesitic-dacitic stratovolcano towers more than 3 km above its northern base and consists of three major volcanic edifices sequentially constructed since about 100,000 years ago 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 1995 that caused the temporary evacuation of the city of Baños at the foot of the volcano, the last major eruption had occurred from 1916 to 1918, although minor activity continued until 1925.
Tungurahua, Ecuador. October, 2012 (path of pyroclastic flows on into valley toward village of Pondoa). (Photo: volcanomike)
See also: Sentinel hub | Landsat 8