Volcán de Pacaya is one of Central America’s most recognizable volcanoes, situated less than 50 kilometers south of Guatemala City. It is a frequent destination for tourists and a constantly monitored source of unrest for local communities. Its almost continuous activity makes it a popular, though hazardous, natural attraction. Given its proximity to major population centers and history of variable eruptions, Pacaya’s status is a matter of ongoing public interest.
The Current State of Activity
Pacaya is currently a persistently active volcano, characterized by frequent, low-level activity. This activity is typically manifested as Strombolian eruptions, involving the rhythmic ejection of incandescent lava fragments from the vent. The volcano maintains constant degassing, releasing columns of steam and magmatic gases, including sulfur dioxide, that typically rise a few hundred meters above the crater.
Small, short-lived lava flows are often a feature of this moderate activity, though they are not always visible to visitors. The most recent significant eruptive period ended in 2021, which included extended lava flows and intermittent ash plumes. Since then, activity has returned to a moderate phase, dominated by thermal anomalies, minor seismic events, and gas output from the Mackenney crater.
Pacaya’s Eruptive History
The current eruptive phase of Pacaya began in 1961, following a dormancy of about 70 years. Since reawakening, the volcano has been in an almost continuous state of activity, defined by frequent, relatively gentle eruptions. Most recorded activity consists of effusive lava flows and Strombolian explosions, characterized by low-viscosity basaltic magma.
This typical pattern is occasionally interrupted by more substantial, explosive events. A notable example is the May 2010 eruption, which ejected ash and debris several thousand meters high. This explosive event caused ashfall in Guatemala City and forced the temporary closure of La Aurora International Airport, demonstrating the volcano’s capacity for variability.
Geological Profile and Type
Pacaya is classified as a basaltic stratovolcano, rising to an elevation of 2,552 meters. This structure is built upon the edge of an older caldera and consists of multiple cones and domes. The currently active vent is located within the Mackenney crater, which sits atop the larger structure.
The primary magma produced is basalt and basaltic andesite, which has a relatively low viscosity. This low viscosity allows gas to escape more easily, resulting in its characteristic effusive activity and moderate Strombolian explosions. These frequent, smaller eruptions prevent the massive pressure buildup that leads to larger, Plinian-style events.
Monitoring and Public Safety
The volcanic activity at Pacaya is closely tracked by the Instituto Nacional de Sismología, Vulcanología, Meteorología e Hidrología (INSIVUMEH), the official Guatemalan monitoring agency. INSIVUMEH employs a network of instruments, including seismic stations to record tremors and continuous GPS to monitor ground deformation. These tools provide real-time data on the volcano’s internal changes, helping to anticipate shifts in activity.
Public safety protocols are in place for the thousands of tourists who visit the national park annually. Access is strictly regulated, and visitors must be accompanied by a licensed guide at all times. Guides are essential for navigating the terrain and staying informed about the current activity level, which can change rapidly.
Visitors must adhere to safety guidelines:
- Adhere to exclusion zones.
- Avoid walking on recent lava flows or fissured areas.
- Be aware that residual heat and hidden pockets of hot gas can persist, posing a risk of burns.
The National Coordinator for Disaster Reduction (CONRED) works with INSIVUMEH to manage alert levels. These levels range from green (normal), yellow (unrest), and red (imminent danger), guiding necessary evacuations and access restrictions for residents and tourists.