The Puracé volcano in southwest Colombia has registered a noticeable uptick in seismic and gas-emission activity over the last 24-hours, prompting authorities to maintain heightened monitoring of one of the country’s most active volcanic systems.
The Colombian Geological Service, known as the SGC, said the latest measurements indicate an increase in seismic signals associated with the movement of fluids beneath the crater. Those signals — including continuous volcanic tremor and distinct long-period events — are typically generated as gases, hot water or small amounts of magma shift through fractures inside the volcanic edifice.
The changes have been visible at the surface. According to a bulletin released by the agency, the volcano has produced columns of gas reaching up to 1.6 kilometers, drifting mostly toward the southwest, sometimes carrying small quantities of ash. While limited in scope, those ash emissions qualify technically as minor eruptions.
Cristian Santacoloma, a volcanologist at the Popayán Volcanological and Seismological Observatory, said the most significant variations occurred on Tuesday, November 25. “We have seen an increase in the constant flow of gases to the surface,” he said, noting that the greyish plume observed during the morning hours contained particulate material consistent with ash. The tremor signals, he added, point to “sustained mobility of fluids within the volcano.”
The Puracé’s summit reaches 4,650 meters (15,256 feet) and sits at the northern end of the Los Coconucos volcanic chain, a line of 15 eruptive centers aligned across the highland terrain of the department of Cauca. Its structure includes two concentric craters and an active fumarolic field on the northern flank known as the Fumarola Lateral. Much of its surface is stained yellow and white from chemical deposits carried by persistent gas discharges.
The region surrounding Puracé is shaped by a long geological history: the volcano rests on an older formation known as Pre-Puracé, which itself developed along the rim of the ancient Chagartón caldera. Its eruptive products include layers of pyroclastic material and andesitic lava flows — evidence of repeated cycles of explosive and effusive activity.
The volcano remains under a Yellow Alert, a mid-tier warning that indicates changes in activity but no immediate threat to surrounding communities. In this state, specialists say, Puracé may produce sporadic ash emissions, small explosions inside the crater, localized sulfur precipitation and, under certain conditions, minor lahars.
The SGC has maintained continuous monitoring of the volcano since 1986. In recent years, its surveillance network has expanded to 32 stations equipped with 65 sensors measuring seismicity, ground deformation, gas composition, temperature and other variables that help scientists detect early signs of escalation.
Authorities have urged residents of Popayán, the departmental capital of Cauca, as well as nearby Indigenous and rural communities to follow official updates and respect any restrictions put in place by park administrators or the National Disaster-Risk Agency (UNGRD). While the current activity is not unusual for Puracé, experts say that sustained changes in seismic patterns requires careful attention.
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