Report on Nevado del Ruiz (Colombia) — 13 April-19 April 2016
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 13 April-19 April 2016
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2016. Report on Nevado del Ruiz (Colombia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 13 April-19 April 2016. Smithsonian Institution and US Geological Survey.
Nevado del Ruiz
4.892°N, 75.324°W; summit elev. 5279 m
All times are local (unless otherwise noted)
Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that during 12-18 April seismicity at Nevado del Ruiz was characterized by long-period earthquakes, episodes of continuous tremor, and pulses of volcanic tremor associated with gas-and-ash emissions. Thermal anomalies near Arenas Crater were periodically identified in satellite images. Significant amounts of water vapor and gas rose from the crater during the week. A gas, steam, and ash plume rose 1.5 km and drifted NW and NE on 12 April. The Alert Level remained at III (Yellow; the second lowest level on a four-color scale).
Geologic Background. 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.