Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers more than 200 km2. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the caldera of an older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. The prominent La Olleta pyroclastic cone located on the SW flank may also have been active in historical time. Steep headwalls of massive landslides cut the flanks. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America's deadliest eruption.
Nevado del Ruiz is a broad, glacier-covered shield-like volcano that covers >200 sq km. The modern cone consists of a cluster of lava domes constructed within the summit caldera of an older Ruiz. The ash-mantled summit of Nevado del Ruiz volcano is seen here from the ESE on December 18, 1985, a little more than a month after the catastrophic eruption of November 13. The devastating 1985 lahars swept down four major river drainages that day and caused more than 23,000 fatalities.
Photo by Norm Banks, 1985 (U.S. Geological Survey).
Last updated 2019-12-03 09:00:03