Report on Nevado del Ruiz (Colombia) — May 2002
Bulletin of the Global Volcanism Network, vol. 27, no. 5 (May 2002)
Managing Editor: Richard Wunderman.
Nevado del Ruiz (Colombia) Largest earthquake swarm since 1985 occurs during June 2002
Please cite this report as:
Global Volcanism Program, 2002. Report on Nevado del Ruiz (Colombia). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 27:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200205-351020.
Nevado del Ruiz
4.892°N, 75.324°W; summit elev. 5279 m
All times are local (unless otherwise noted)
The last reported activity at Nevado del Ruiz was a moderate earthquake swarm during late March through April 1999 (BGVN 24:04). On 9 June 2002 at 2300 another swarm of volcano-tectonic earthquakes began. Following the swarm, hundreds of hybrid earthquakes were recorded, with more than 1,300 earthquakes occurring in 16 hours. High seismicity marked the following 3 days during which a total of ~2,300 earthquakes were recorded. This is the highest number of events recorded per day at Nevado del Ruiz since 1985. According to news reports, the earthquakes had magnitudes up to ~2.3 and occurred at depths of 0.5-3 km. In addition to heightened seismicity that was felt by people near the volcano, jet-like sounds corresponded with some of the hybrid earthquakes, and a strong odor of SO2 was reported near the summit. No ash emissions were reported, and seismicity decreased by 13 June. At the height of the activity the Alert Level was at Orange.
General References. Lescinsky, D., 1990, Nevado del Ruiz volcano, Colombia: a comprehensive bibliography: JVGR, v. 42, p. 211-224.
Williams, S., ed., 1990, Nevado del Ruiz, Colombia; (I) JVGR, v. 41, p. 1-379 (18 papers); (II) JVGR, v. 42, p. 1-224 (13 papers).
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: John Macario Londoño Bonilla, Volcanological and Seismological Observatory of INGEOMINAS, Avenida 12 Octubre 15-47, Manizales, Colombia (URL: https://www2.sgc.gov.co/); El Tiempo; La Libertad.