Observatorio Vulcanológico y Sismológico de Popayán, Servicio Geologico Colombiano (SGC), reported that during 19-25 April the number and magnitudes of earthquakes at Puracé was similar to the previous week. Signals included 72 volcano-tectonic (VT) events, indicating rock fracturing, along with 207 long-period (LP) events and 14 low-energy tremor pulses, indicating fluid movement. Data from the GNSS (Global Navigation Satellite System) geodetic network continued to show inflation on the centimeter scale. Sulfur dioxide emissions were lower than the previous week, with values of 937-992 tonnes per day, and gas plumes drifted NW. During a field visit on 22 April scientists observed no changes to the crack near Puracé and Curiquinga volcanoes, and no visible gas emissions. Additional cracks, oriented NW-SE, were observed, in addition to volcanic ash deposits that were likely emplaced on 29 March. The Alert Level remained at Yellow (the second lowest 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)