Report on Cumbal (Colombia) — 18 July-24 July 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 18 July-24 July 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Cumbal (Colombia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 18 July-24 July 2012. Smithsonian Institution and US Geological Survey.
0.95°N, 77.87°W; summit elev. 4764 m
All times are local (unless otherwise noted)
According to INGEOMINAS, the Observatorio de Pasto reported that during 18-24 July seismic activity at Cumbal had decreased. Variable amounts of gas emissions, mostly steam, were observed in the web camera located in Cumbal town (9 km SE) during periods of clear weather, which occurred during 20-21 July. The emissions originated from fumarolic fields located in the main crater on the NE side of Cumbal and Mundo Nuevo crater on the SW side. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").
Geologic Background. Many youthful lava flows extend from the glacier-capped Cumbal volcano, the southernmost historically active volcano of Colombia. The volcano is elongated in a NE-SW direction and is composed primarily of andesitic-dacitic lava flows. Two fumarolically active craters occupy the summit ridge: the main crater on the NE side and Mundo Nuevo crater on the SW. A young lava dome occupies the 250-m-wide summit crater, and eruptions from the upper E flank produced a 6-km-long lava field. The oldest crater lies NNE of the summit crater, suggesting SW-ward migration of activity. Explosive eruptions in 1877 and 1926 are the only known historical activity. Thermal springs are located on the SE flanks.