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Report on Irazu (Costa Rica) — January 1983


Scientific Event Alert Network Bulletin, vol. 8, no. 1 (January 1983)
Managing Editor: Lindsay McClelland.

Irazu (Costa Rica) Temperature and gas data

Please cite this report as:

Global Volcanism Program, 1983. Report on Irazu (Costa Rica) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 8:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198301-345060


Costa Rica

9.979°N, 83.852°W; summit elev. 3436 m

All times are local (unless otherwise noted)

The low temperatures measured in 1982 do not vary from the results of June 1981. Between 5 December and 20 December 1982, a team from PIRPSEV (CNRS) and a volcanological team from the Universidad Nacional de Costa Rica sampled gases from Irazú (table 1).

Table 1. Average values of gas compositions collected between 5 and 20 December 1982 compared to earlier data.

Year SO2% CO2% H2% H2S% CO% CH4% He (ppm)
1981 0.106 98.02 0.015 1.860 0.003 0 8.4
1982 0.007 99.8 0 0.119 0.002 0 6.0

Geological Summary. The massive Irazú volcano in Costa Rica, immediately E of the capital city of San José, covers an area of 500 km2 and is vegetated to within a few hundred meters of its broad summit crater complex. At least 10 satellitic cones are located on its S flank. No lava effusion is known since the eruption of the 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 main crater, which contains a small lake. The first well-documented 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. Phreatic activity reported in 1994 may have been a landslide event from the fumarolic area on the NW summit (Fallas et al., 2018).

Information Contacts: J. Cheminée, IPG, Paris; M. Javoy and H. Delorme, Univ. de Paris.