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
Purace
Colombia
2.3095°N, 76.3948°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. Puracé is an active andesitic volcano with a 600-m-diameter summit crater at the NW end of the Los Coconucos Volcanic Chain. This volcanic complex includes nine composite and five monogenetic volcanoes, extending from the Puracé crater more than 6 km SE to the summit of Pan de Azúcar stratovolcano. The dacitic massif which the complex is built on extends about 13 km NW-SE and 10 km NE-SW. Frequent small to moderate explosive eruptions reported since 1816 CE have modified the morphology of the summit crater, with the largest eruptions in 1849, 1869, and 1885.
Information Contacts: H. Cepeda, INGEOMINAS, Popayán; M. Martini, Univ di Firenze, Italy.
