Report on Irazu (Costa Rica) — November 1992
Bulletin of the Global Volcanism Network, vol. 17, no. 11 (November 1992)
Managing Editor: Lindsay McClelland.
Irazu (Costa Rica) Fumarolic activity continues
Please cite this report as:
Global Volcanism Program, 1992. Report on Irazu (Costa Rica) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 17:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199211-345060
9.979°N, 83.852°W; summit elev. 3432 m
All times are local (unless otherwise noted)
Fumarolic activity continued from the lake in the main crater. The temperature of the "steaming ground" on the debris fans N of the lake was 92°C on 1 December, and fumaroles on the NE side of the lake were at 93°C. Lake temperature ranged from 19 to 24°C. All were similar to October values. Lake level was unchanged, as were temperature and pH of both hot and cold springs around the volcano.
Geological Summary. Irazú, one of Costa Rica's most active volcanoes, rises immediately E of the capital city of San José. The massive volcano covers an area of 500 km2 and is vegetated to within a few hundred meters of its broad flat-topped summit crater complex. At least 10 satellitic cones are located on its S flank. No lava flows have been identified since the eruption of the massive Cervantes lava flows from S-flank vents about 14,000 years ago, and all known Holocene eruptions have been explosive. The focus of eruptions at the summit crater complex has migrated to the W towards the historically active crater, which contains a small lake of variable size and color. Although eruptions may have occurred around the time of the Spanish conquest, the first well-documented historical eruption occurred in 1723, and frequent explosive eruptions have occurred since. Ashfall from the last major eruption during 1963-65 caused significant disruption to San José and surrounding areas.
Information Contacts: G. Soto and R. Barquero, ICE.