Report on Irazu (Costa Rica) — July 1981
Scientific Event Alert Network Bulletin, vol. 6, no. 7 (July 1981)
Managing Editor: Lindsay McClelland.
Irazu (Costa Rica) Low-temperature gases collected
Please cite this report as:
Global Volcanism Program, 1981. Report on Irazu (Costa Rica). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 6:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198107-345060.
9.979°N, 83.852°W; summit elev. 3432 m
All times are local (unless otherwise noted)
Between 14 June and 11 July, personnel from PIRPSEV, CNRS, and the volcano observation section of IPG sampled gases from five Central American volcanoes. Low-temperature gases were collected at Turrialba and Irazú.
Geologic Background. 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: H. Delorme, Univ. de Paris; J.L. Cheminée, IPG, Paris.