Exploring Bolivia's Volcanic Landscape: A Guide

Bolivia is home to numerous volcanoes, both active and extinct, with the active ones located in the west of the country. Bolivia's volcanoes are part of the Andean Volcanic Belt, specifically the Central Volcanic Zone, which spans parts of Peru, Chile, Bolivia, and Argentina. The country's highest volcano, Nevado del Sajama, rises to 6,542 meters (21,463 feet) about 20 kilometers east of the Chilean border. Bolivia's volcanoes vary in height, with some exceeding 6,000 meters, and pose varying levels of hazard to the surrounding areas.

Bolivia's volcanoes: active, dormant, and extinct

Bolivia is home to several active and extinct volcanoes. The active volcanoes are located in western Bolivia and form the Cordillera Occidental, which is the western boundary of the Altiplano plateau. Many of these active volcanoes are shared with Chile. All Cenozoic volcanoes in Bolivia are part of the Central Volcanic Zone (CVZ) of the Andean Volcanic Belt, which was formed by the subduction of the Nazca Plate under the South American Plate. The Central Volcanic Zone is a significant upper Cenozoic volcanic province.

Some of the active volcanoes in Bolivia include:

• Cerro Bonete (Lipez)
• Moiro (or Cerro Negro)
• Licancabur (shared with Chile)
• Acotango (viewed from Chile)
• Ollague (viewed from Bolivia)

In addition to the active volcanoes, Bolivia also has several dormant and extinct volcanoes. The remnants of ancient volcanoes can be found around the Precambrian Guaporé Shield in the eastern part of the country. One example of an extinct volcano in Bolivia is the Sajama stratovolcano.

The volcanoes of Bolivia offer a glimpse into the country's geological history and contribute to the diverse landscape of the region.

The Altiplano–Puna volcanic complex

The Altiplano-Puna Volcanic Complex (APVC) is a major silicic volcanic province in the Central Volcanic Zone of the Andean Volcanic Belt. The complex covers an area of about 50,000 square kilometres between the Atacama basin and the Altiplano, with an estimated volume of around 15,000 cubic kilometres. The APVC is characterised by large nested caldera complexes, which have been the source of huge, regionally distributed ignimbrite sheets. The ignimbrites are typically calc-alkaline, high-K dacites with minor rhyolites, and their source magmas are usually phenocryst-rich.

The Altiplano-Puna Volcanic Complex has been active since the late Miocene, with an intense episode of ignimbrite volcanism starting around 10.4 million years ago. While there have been no major ignimbrites erupted in recent times, Holocene activity within the complex has occurred in the form of large silicic lava domes and flows. These are interpreted as leaks from a large crustal magma generation zone underlying the APVC. The region also features several geothermal manifestations, including two large active geothermal fields at El Tatio in Chile and Sol de Manana in Bolivia.

Seismic studies have revealed the presence of a low-velocity zone at a depth of approximately 19 kilometres below the complex, indicating the existence of a sill-like magma body. The magma body underlying the Altiplano-Puna Volcanic Complex is one of the largest imaged magma reservoirs on Earth, containing an estimated 500,000 cubic kilometres of partial melt. The uplift of the Altiplano-Puna plateau, driven by the intrusion of magma, is a crucial process in the formation of continents.

Holocene volcanoes in Bolivia

Bolivia is home to numerous active and extinct volcanoes, with active volcanoes located in the west of the country. The country has seven Holocene volcanoes, and many of its active volcanoes are shared with Chile. Holocene volcanoes in Bolivia include:

• Uturuncu: Uturuncu is a dormant volcano in the Sur Lípez Province of Bolivia. It is the highest peak in southwestern Bolivia, rising to 6,008 metres (19,711 ft). Uturuncu has two summit peaks and consists of a complex of lava domes and lava flows. The volcano has traces of former glaciation and active fumaroles in the summit region. While there is no evidence of Holocene activity, recent unrest such as ground deformation and seismicity indicate the presence of a magmatic system.
• Irruputuncu: Irruputuncu is a small stratovolcano on the Chile-Bolivia border. It has two summit craters, with a small lava dome and fumarolic activity in the southern crater.
• Olca-Paruma: Olca-Paruma is a group of three stratovolcanoes forming a 15-km-long ridge along the Chile-Bolivia border. The only known historical activity was intense fumarolic activity.
• Licancabur: Licancabur is an active stratovolcano on the Chile-Bolivia border. It has a symmetric shape and contains one of the world's highest lakes in its summit crater. Young lava flows are present on its flanks.
• Guayaques: Guayaques is a group of lava domes forming a 10-km-long chain on the Chile-Bolivia border. Thick, viscous lava flows extend up to 3 km from the vents, with the youngest domes appearing to be in the north.
• Acotango: Acotango is a poorly known volcano on the Chile-Bolivia border. A young lava flow on its northern flank suggests eruptions within the last 10,000 years, indicating possible activity.

The Central Volcanic Zone

The CVZ is characterised by a thick continental crust of approximately 70 km (43-44 mi). Within this zone, there are 44 major and 18 minor active volcanic centres. The zone also contains at least six potentially active large silicic volcanic systems, including those of the Altiplano-Puna Volcanic Complex, as well as several others in Bolivia and neighbouring countries.

The CVZ showcases a diverse range of geological phenomena. The magmas emitted by the CVZ are dominated by silicic andesites and dacites, and the zone has emitted a significant volume of ignimbrites, which dominate the local landscape. Despite a relatively low frequency and long recurrence between eruptions compared to other volcanic arcs, the CVZ has a history of catastrophic eruptions, including super-eruptions of more than 450 km³ of erupted magma.

The CVZ has a broad range of volcano-tectonic settings, including rift systems, extensional zones, transpressional faults, subduction of mid-ocean ridges, and seamount chains. The belt is formed by the subduction of the Nazca Plate and the Antarctic Plate underneath the South American Plate.

The Andean Central Volcanic Arc

The CVZ is one of the four volcanic zones of the Andes, the others being the Northern Volcanic Zone (NVZ), the Southern Volcanic Zone (SVZ), and the Austral Volcanic Zone (AVZ). These segments are separated by volcanic gaps where the dips of the subducting plates are too shallow to sustain volcanism. The Central Volcanic Zone is limited to the south by the Pampean flat-slab segment, a region devoid of volcanism due to the lower subduction angle caused by the subduction of the Juan Fernández Ridge.

The Central Volcanic Zone contains large silicic volcanic systems, including those of the Altiplano-Puna Volcanic Complex, such as Cerro Panizos, Pastos Grandes, Cerro Guacha, and La Pacana. Other silicic systems in the CVZ include Los Frailes ignimbrite plateau in Bolivia, and the caldera complexes of Incapillo and Cerro Galán in Argentina. The diversity of the CVZ is further illustrated by the presence of potentially active large silicic volcanic systems.

The Central Volcanic Zone is a result of the subduction of the Nazca Plate under western South America along the Peru-Chile Trench. This subduction process is responsible for igniting volcanic activity and creating a captivating volcanic belt that showcases a variety of activity styles, products, and morphologies. The belt, in turn, is part of the Ring of Fire in the Pacific Ocean basin, which is marked by extensive oceanic trenches, volcanic arcs, and belts.

Frequently asked questions