Observatorio Vulcanológico y Sismológico de Popayán, Servicio Geologico Colombiano (SGC) reported that the daily number of both volcanic tremor (VT) and long-period (LP) seismic events at Puracé trended downward during 14-21 May, and by the end of the week had reached pre-29 April levels. The VT events had low magnitudes and were located at depths up to 2.4 km beneath the volcano and its E flank. The largest VT events, M 1.5, were recorded at 1821 on 14 May and at 0711 on 16 May. LP earthquakes were located at depths less than 3 km beneath the volcano and its N flank. Inclement weather often prevented visual observations of emissions, though during 15-16 May a gas plume rose as high as 650 m above the summit and drifted W. Both carbon dioxide and sulfur dioxide emissions remained above baseline levels. The Alert Level remained at Orange (the second highest level on a four-color scale).

Geological Summary. Puracé in Colombia consists of an andesitic stratovolcano with a 500-m-wide summit crater 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.

Source: Servicio Geológico Colombiano (SGC)