Report on Nevado del Ruiz (Colombia) — February 1990
Bulletin of the Global Volcanism Network, vol. 15, no. 2 (February 1990)
Managing Editor: Lindsay McClelland.
Nevado del Ruiz (Colombia) Seismicity remains low
Please cite this report as:
Global Volcanism Program, 1990. Report on Nevado del Ruiz (Colombia). In: McClelland, L. (ed.), Bulletin of the Global Volcanism Network, 15:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199002-351020.
Nevado del Ruiz
4.892°N, 75.324°W; summit elev. 5279 m
All times are local (unless otherwise noted)
Seismic energy release and the number of earthquakes were at low levels in February. A swarm of low-energy, high-frequency events occurred NW of Arenas crater at 6.5 km depth on 7 February. Pulses of low-energy tremor were also detected. The average measured dry-tilt change in February was only 4 µrad. Variations in electronic tilt (at the Refugio station) were associated with tremor (1.5-2.0 km depth) 14-16 February.
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.
Information Contacts: C. Carvajal, INGEOMINAS, Manizales.