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 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.

Source: Servicio Geológico Colombiano (SGC)