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Report on Purace (Colombia) — January 1993


Bulletin of the Global Volcanism Network, vol. 18, no. 1 (January 1993)
Managing Editor: Lindsay McClelland.

Purace (Colombia) Summit fumarole gas analyses reported

Please cite this report as:

Global Volcanism Program, 1993. Report on Purace (Colombia) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 18:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199301-351060



2.32°N, 76.4°W; summit elev. 4650 m

All times are local (unless otherwise noted)

Fumaroles near the summit were visited by Héctor Cepeda, other geologists from INGEOMINAS, Marino Martini, and Franco Prati. The temperature of the gas sample (table 1) was 170°C, and geologists inferred a significant magmatic component.

Table 1. Analysis of gases collected at Galeras (26 November 1992) and Puracé (28 November 1992). Percentages shown are for dry gas. Courtesy of M. Martini.

Gas Galeras Puracé
CO2 70.23 73.84
SO2 9.90 14.66
H2S 6.72 3.25
HCl 8.36 7.53
HF 0.73 0.041
H2 3.35 0.0034
CO 0.16 0.0005
N2 0.48 0.62
H 0.0037 --
B -- 0.042
Vol % H20 91.48 98.09
Temp 642°C 170°C

Geological Summary. One of the most active volcanoes of Colombia, Puracé consists of an andesitic stratovolcano with a 500-m-wide summit crater that was constructed over a dacitic shield volcano. It lies at the NW end of a volcanic massif opposite Pan de Azúcar stratovolcano, 6 km SE. A NW-SE-trending group of seven cones and craters, Los Coconucos, lies between the two larger edifices. Frequent explosive eruptions in the 19th and 20th centuries have modified the morphology of the summit crater. The largest eruptions occurred in 1849, 1869, and 1885.

Information Contacts: H. Cepeda, INGEOMINAS, Popayán; M. Martini, Univ di Firenze, Italy.