Report on Purace (Colombia) — April 1977
Natural Science Event Bulletin, vol. 2, no. 4 (April 1977)
Managing Editor: David Squires.
Purace (Colombia) Another ash emission seen on 25 March
Please cite this report as:
Global Volcanism Program, 1977. Report on Purace (Colombia) (Squires, D., ed.). Natural Science Event Bulletin, 2:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.NSEB197704-351060.
2.32°N, 76.4°W; summit elev. 4650 m
All times are local (unless otherwise noted)
The eruption of a black and gray ash cloud began at 0545 on 19 March from two new vents. Fine gray ash was deposited as far as 7 km away. The volcano was visited a few days later by Guillermo Cajino, who noted a small tremor and rumbling noises while 5 km from Puracé at 2300 on 24 March. The next day, he observed the emission of a gas column from the two vents, which scattered ash SE over the flanks. By 28 March the fume clouds rose only 200 m.
Geologic Background. 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: U.S. Dept. of State.