Argentina is home to a significant number of volcanoes, mostly situated along the western boundary following the spine of the Andes Mountains. These geological features result directly from the immense tectonic forces shaping the South American continent. The presence of these peaks, many of which are towering stratovolcanoes, defines much of the landscape and natural history of the western provinces.
The Geological Mechanism Driving Volcanism
The existence of volcanoes in Argentina is a direct consequence of plate tectonics along the continent’s western edge. This region is part of the larger Pacific Ring of Fire, a zone characterized by frequent earthquakes and volcanic activity. Volcanism is driven by the subduction of the Nazca Plate beneath the South American Plate, where the denser oceanic plate slides underneath the continental plate.
As the Nazca Plate descends deep into the Earth’s mantle, heat and pressure cause water and volatile compounds to be released. These fluids rise into the overlying mantle wedge, lowering its melting point and generating buoyant magma. This magma ascends through the South American crust, eventually leading to eruptions that form the chain of Andean volcanoes. The rate of convergence between these plates, approximately 6.7 centimeters per year, sustains the geological activity.
This process results in three distinct volcanic belts along the Andes: the Northern, Central, and Southern Volcanic Zones. Argentine volcanoes are primarily concentrated within the Central and Southern zones, stretching from the high-altitude Puna de Atacama plateau southward into Patagonia. The magma’s composition, often andesitic, results in the construction of tall, steep-sided stratovolcanoes, the most common volcanic form in the Argentine Andes.
Major Volcanic Regions and Notable Peaks
Argentina’s volcanoes are distributed across several regions, largely straddling the border with Chile. The Central Volcanic Zone includes the high-altitude Puna region, an arid plateau in the northwest. The Llullaillaco volcano, standing at 6,739 meters, is located here and is recognized as one of the highest historically active volcanoes on Earth.
The Puna also contains Nevados Ojos del Salado, which reaches 6,893 meters and is the world’s highest active volcano. This peak, along with Incahuasi and Lastarria, are massive stratovolcanoes marking the boundary with Chile. The area’s geology also includes large collapse features, such as the Cerro Galán caldera.
The Cuyo region, including Mendoza Province, features notable peaks like Tupungato, a stratovolcano rising to 6,570 meters. Volcanic systems here extend into the Southern Volcanic Zone, home to the Payenia Volcanic Province. Payenia is characterized by extensive fields of basaltic lava flows and numerous small cinder cones, contrasting with the large stratovolcanoes further north.
In the Patagonian region, volcanoes like Domuyo and Lanín are prominent features. Domuyo, often called the “Roof of Patagonia,” shows signs of recent activity and hosts one of the largest geothermal fields in the world. Lanín, a conical stratovolcano in Neuquén Province, is a well-known landmark. These peaks represent the southern extent of the active volcanic arc in Argentina.
Current Activity Status and Monitoring Efforts
While Argentina is home to many volcanoes, the majority are considered dormant or extinct. However, approximately 38 volcanoes are classified as active or potentially active, concentrated along the Andes. For a volcano to be considered active, it must show signs of recent unrest or have a history of Holocene eruptions (within the last 10,000 years).
To manage risks, the Argentine government established the Observatorio Argentino de Vigilancia Volcánica (OAVV), a specialized department within the Servicio Geológico Minero Argentino (SEGEMAR). The OAVV continuously monitors active volcanoes to provide early warnings to Civil Protection authorities and the public. This oversight helps mitigate the potential impact of an eruption, such as ashfall or lahars.
SEGEMAR employs sophisticated monitoring methods, including both visual and instrumental techniques. Scientists track seismic activity, looking for small earthquakes that indicate magma or fluid movement beneath the surface. They also use satellite data to detect ground deformation, which is the subtle swelling or sinking of the volcano’s flanks due to pressure changes in the magma chamber. Thermal anomalies are also monitored via satellite.
Specific volcanic complexes are under surveillance due to signs of unrest. For instance, the Laguna del Maule complex, situated on the border between Mendoza and Neuquén, has shown increased seismicity and rapid ground uplift, with deformation measured up to 4.2 centimeters per month. Complexes like Planchón-Peteroa are also monitored closely due to seismic activity, indicating fluid movement that could precede an eruption. These efforts ensure that the activity of these volcanoes is closely watched.