BackgroundInca legends report that the top of Altar collapsed after seven years of activity in about 1460, but the caldera is considered to be much older than this by geologists. 9 major peaks over 5,000 metres (16,400 ft) form a horseshoe-shaped ridge about 3 km across, surrounding a central basin that contains a crater lake at about 4,200 m (13,800 ft), known as Laguna Collanes or Laguna Amarilla.
- Hall, Minard L. (1977). "El Volcanismo en el Ecuador". Sección Nacional del Ecuador. p. 120 pp
- Smithsonian / GVP additonal reports for Altar
See also: Sentinel hub | Landsat 8