Volcanoes in Colombia

Colombia has 13 Holocene volcanoes arranged along the Cordillera Central of the Andes, forming the northernmost segment of the Andean volcanic chain in South America. These volcanoes, rising to extraordinary heights — four exceed 5,000 m (16,400 ft) — include some of the most dangerous and historically devastating volcanic centers on the continent. The 1985 eruption of [[volcano:nevado-del-ruiz|Nevado del Ruiz]], which killed approximately 23,000 people in the city of Armero through catastrophic lahars, stands as the [[ranking:deadliest-eruptions|second deadliest volcanic disaster of the 20th century]] and a defining moment in volcanological history.

Colombia's volcanism is driven by the subduction of the oceanic Nazca Plate beneath the continental South American Plate at the Peru-Chile Trench. The subducting slab descends beneath the Andes at varying angles, generating magma that rises through thick continental crust exceeding 40 km to feed the volcanic chain. The Ruiz-Tolima volcanic massif in central Colombia — containing [[volcano:nevado-del-ruiz|Nevado del Ruiz]], [[volcano:nevado-del-tolima|Nevado del Tolima]], Cerro Bravo, and several other centers — represents the most concentrated and hazardous volcanic complex in the country.

The Colombian volcanic chain extends approximately 600 km from Cumbal near the [[country:ecuador|Ecuadorian]] border in the south to Romeral in the north. All 13 volcanoes sit on continental crust in the subduction zone setting, producing predominantly andesitic to dacitic magmas capable of highly explosive eruptions. The geological record includes 130 confirmed eruptions, with a [[special:volcanic-explosivity-index|VEI]] distribution heavily weighted toward moderate-to-large events: 18 eruptions at VEI 4 and one at VEI 5.

Glacier-capped summits at Ruiz, Tolima, Huila, and Santa Isabel add a critical lahar hazard dimension, as eruptions can rapidly melt ice and generate devastating mudflows that travel tens of kilometers downstream. [[volcano:galeras|Galeras]], located directly above the city of Pasto (population 500,000+), is one of the most dangerous volcanoes in Colombia and has been designated a UN Decade Volcano due to its proximity to dense population and its history of sudden explosive eruptions.

Colombia's volcanoes owe their existence to the convergence of two major tectonic plates along South America's Pacific margin. The Nazca Plate, a dense oceanic plate in the eastern Pacific, subducts beneath the South American Plate at the Peru-Chile (or Peru-Colombia) Trench at a rate of approximately 5–6 cm per year. As the Nazca Plate descends to depths of 100–200 km beneath the Andes, dehydration of the subducting slab releases fluids that lower the melting point of the overlying mantle wedge, generating magma.

This magma ascends through the exceptionally thick continental crust of the Colombian Andes — estimated at 35–45 km — undergoing fractional crystallization and assimilation along the way. The result is predominantly intermediate to silicic magma compositions (andesite to dacite) that are inherently gas-rich and viscous, favoring explosive eruption styles. This is why Colombia's volcanic record is dominated by moderate-to-large explosive events rather than effusive lava flows.

The volcanic chain follows the Cordillera Central, one of three parallel ranges that make up the Colombian Andes. This range is bounded by major fault systems — the Romeral Fault to the west and the Palestina Fault to the east — which provide structural pathways for magma ascent. The northern terminus of Andean volcanism in Colombia occurs near Romeral volcano, beyond which the subduction angle becomes too shallow to generate significant melt.

The country lies firmly within the [[special:ring-of-fire|Ring of Fire]], and its volcanic arc connects southward with [[country:ecuador|Ecuador's]] volcanic chain and northward with the Caribbean tectonic domain.

**Nevado del Ruiz** — [[volcano:nevado-del-ruiz|Nevado del Ruiz]] is Colombia's most notorious volcano and one of the deadliest in world history. This broad, glacier-covered [[special:types-of-volcanoes|stratovolcano]] rises to 5,279 m (17,320 ft) and has produced 20 confirmed eruptions, including the catastrophic November 13, 1985 event. A relatively small VEI 3 eruption melted summit glaciers and generated lahars that raced 74 km down river valleys, obliterating the town of Armero and killing approximately 23,000 people.

Ruiz remained active in 2025, with elevated seismicity and ash emissions prompting ongoing monitoring by Colombia's Servicio Geológico Colombiano.

**Galeras** — [[volcano:galeras|Galeras]] is Colombia's most frequently active volcano, with 36 confirmed eruptions, and one of the most dangerous due to its position directly above Pasto (population ~500,000). This complex stratovolcano rises to 4,276 m (14,029 ft) and was designated a UN Decade Volcano in the 1990s. A tragic 1993 eruption killed six scientists and three tourists who were inside the crater conducting research.

Galeras last erupted in 2014.

**Nevado del Huila** — At 5,364 m (17,598 ft), [[volcano:nevado-del-huila|Nevado del Huila]] is the highest peak in the Colombian Andes and the tallest active volcano in the country. It is an elongated, glacier-covered stratovolcano that was thought to be dormant until a series of eruptions beginning in 2007 generated lahars along the Páez River. Its most recent activity occurred in 2012.

**Nevado del Tolima** — [[volcano:nevado-del-tolima|Nevado del Tolima]] is a steep, glaciated stratovolcano rising to 5,215 m (17,110 ft), forming a prominent peak southeast of Nevado del Ruiz. With 12 confirmed eruptions and a VEI maximum of 5, Tolima has the potential for highly explosive activity. Its last confirmed eruption occurred in 1943.

**Puracé** — [[volcano:purace|Puracé]] is one of Colombia's most active volcanoes, with 29 confirmed eruptions. This andesitic stratovolcano rises to 4,650 m (15,256 ft) in the Los Coconucos chain of southwestern Colombia. Puracé showed renewed activity in 2025.

**Cerro Machín** — Though only 2,749 m (9,019 ft) tall, [[volcano:machin|Cerro Machín]] is considered by many volcanologists to be Colombia's most potentially dangerous volcano. This small dacitic stratovolcano lies within 20 km of the city of Ibagué (population 530,000+) and near major transport routes. Its silicic magma composition favors catastrophic explosive eruptions.

**Cumbal** — [[volcano:cumbal|Cumbal]] is the southernmost historically active volcano in Colombia, a glacier-capped stratovolcano rising to 4,764 m (15,630 ft) near the Ecuadorian border, last erupting in 1926.

Colombia's volcanic record encompasses 130 confirmed eruptions across 13 Holocene volcanoes, with a history that includes some of South America's most devastating volcanic disasters. The VEI distribution reveals a notable concentration of moderate-to-large events: 25 eruptions at VEI 3, 18 at VEI 4, and one at VEI 5, with comparatively fewer small eruptions — an unusual pattern reflecting the explosive character of Colombian volcanism.

The most consequential eruption in Colombian history occurred on November 13, 1985, at [[volcano:nevado-del-ruiz|Nevado del Ruiz]]. A relatively modest VEI 3 eruption produced pyroclastic flows that rapidly melted portions of the summit glacier. The resulting lahars cascaded down river valleys at speeds exceeding 60 km/h, traveling up to 74 km.

The city of Armero was engulfed in a 5-meter-thick wave of mud. Approximately 23,000 of the town's 29,000 residents perished. The disaster became a landmark case in volcanic risk management: scientists had warned of the danger months in advance, but evacuation orders were delayed by bureaucratic failures.

The Armero tragedy directly led to the establishment of modern volcanic early warning systems worldwide.

[[volcano:galeras|Galeras]] has dominated Colombia's modern eruption record, with frequent explosive eruptions throughout the 20th and early 21st centuries. The January 14, 1993 eruption killed six volcanologists and three tourists who were conducting measurements inside the crater, transforming safety protocols for fieldwork on active volcanoes globally.

Historical eruptions at Cerro Bravo (VEI 4 events in the medieval period), Doña Juana (VEI 4 in 1906), and Puracé (29 eruptions spanning centuries) have maintained Colombia's position as one of the most volcanically significant countries in the Americas. The 2007 discovery that Nevado del Huila — long considered dormant — was generating lahars added a new dimension to the country's volcanic hazard profile.

Colombia faces exceptionally severe volcanic hazards, primarily because its glacier-capped Andean volcanoes combine explosive potential with lahar-generating capacity. The Armero disaster of 1985 demonstrated that even a moderate eruption can produce catastrophic results when pyroclastic material interacts with summit ice. Lahars remain the single greatest volcanic threat in Colombia: Nevado del Ruiz, Nevado del Tolima, and Nevado del Huila all retain significant glacier cover, and major river valleys downstream pass through populated areas.

Pyroclastic flows represent the most lethal proximal hazard. Cerro Machín's dacitic magma composition makes it especially prone to dome-collapse pyroclastic flows that could impact Ibagué. Galeras poses a persistent threat to Pasto, where Vulcanian explosions can generate pyroclastic surges reaching the city's outskirts.

Ashfall from large eruptions could affect Bogotá, Cali, and Medellín. The Servicio Geológico Colombiano (SGC) operates a comprehensive monitoring network including seismometers, tiltmeters, GPS stations, and gas sensors. Since the Armero disaster, Colombia has invested significantly in volcanic early warning systems, and the country's monitoring capabilities are now among the most advanced in Latin America.

Colombia's 13 volcanoes are distributed along approximately 600 km of the Cordillera Central, extending from Cumbal (0.95°N) near the Ecuadorian border to Romeral (5.2°N) north of Manizales. The Ruiz-Tolima massif contains the densest concentration: Romeral, Cerro Bravo, Santa Isabel, Nevado del Ruiz, Nevado del Tolima, and Cerro Machín within ~80 km. Nevado del Huila stands in relative isolation further south.

The southern segment — Sotará, Puracé, Doña Juana, Galeras, Azufral, and Cumbal — follows the narrowing Cordillera toward Ecuador.

Colombia's volcanoes profoundly influence the nation's geography, agriculture, and cultural landscape. The fertile volcanic soils of the Cordillera Central support the Colombian coffee industry — one of the world's largest — with the UNESCO-designated Coffee Cultural Landscape situated in the shadow of Nevado del Ruiz. The Armero disaster of 1985 left an indelible mark on Colombian national consciousness and catalyzed significant investment in geological monitoring and risk management.

Los Nevados National Natural Park, encompassing Ruiz, Tolima, and Santa Isabel, draws hikers and mountaineers to the volcanic highlands. Thermal springs fed by volcanic heat support local tourism economies around Puracé and the Ruiz-Tolima region.

Los Nevados National Natural Park is Colombia's premier volcanic tourism destination, offering trekking access to the flanks of Nevado del Ruiz, Nevado del Tolima, and Santa Isabel through stunning páramo ecosystems. However, summit access to Ruiz is frequently restricted due to volcanic activity. Puracé National Natural Park offers hiking to the sulfurous summit crater.

The Galeras region features hot springs, though summit access is restricted. The town of Armero serves as a memorial site and educational destination. Visitors should acclimate to altitude gradually, as summits exceed 4,500 m (14,760 ft), and check SGC alert levels before all trips.