Volcanoes in Peru

Peru has 13 Holocene volcanoes located along the western Andes in the southern part of the country, forming part of the Central Volcanic Zone (CVZ) of the Andean volcanic arc. These volcanoes include some of the highest volcanic edifices on Earth — [[volcano:coropuna|Coropuna]] reaches 6,377 m (20,922 ft), [[volcano:el-misti|El Misti]] rises to 5,793 m (19,006 ft), and [[volcano:ubinas|Ubinas]], Peru's most active volcano, stands at 5,608 m (18,399 ft). Among them, [[volcano:huaynaputina|Huaynaputina]] produced the largest historical eruption in South America: a cataclysmic VEI 6 event in 1600 CE that injected massive quantities of sulfur dioxide into the stratosphere and contributed to one of the most severe climate perturbations of the past millennium.

Peru's volcanism results from the subduction of the oceanic Nazca Plate beneath the South American Plate at the Peru-Chile Trench. The volcanic chain in southern Peru lies within the CVZ, where the subducting slab descends at a relatively steep angle (~30°). North of about 15°S latitude, the subduction angle flattens dramatically (the Peruvian flat slab), suppressing volcanism entirely — explaining why Peru's volcanoes are confined to the far south.

The current volcanic landscape is dominated by [[volcano:sabancaya|Sabancaya]], which has been in near-continuous eruption since 2016, producing daily to weekly ash explosions visible from the Colca Valley. [[volcano:ubinas|Ubinas]] erupted most recently in 2024, and [[volcano:el-misti|El Misti]] — the iconic volcano overlooking Arequipa, Peru's second-largest city (~1 million residents) — poses one of the most significant volcanic threats to any major city in South America. With 63 confirmed eruptions across all centers, Peru's volcanic chain demands ongoing vigilance from the Instituto Geofísico del Perú (IGP) and the Observatorio Vulcanológico del INGEMMET (OVI).

Peru's volcanic chain exists because of the subduction of the Nazca Plate beneath the South American Plate at the Peru-Chile Trench. As the oceanic plate descends, fluids released from hydrated minerals trigger partial melting of the mantle wedge, generating magma that ascends through the extraordinarily thick Andean crust — estimated at 50–70 km in southern Peru, among the thickest continental crust on Earth.

Critically, Peru's volcanism is confined to the far south because of variations in subduction geometry. North of ~15°S, the Nazca Plate descends at a very shallow angle (the 'Peruvian flat slab'), remaining in contact with the base of the overriding plate and suppressing conditions needed for magma generation. Only south of this latitude does the slab steepen to ~30°, enabling the normal subduction-driven volcanism of the CVZ.

This creates a sharp volcanic front: there are essentially no active volcanoes in central or northern Peru despite continued subduction offshore.

The southern Peruvian volcanic arc connects with the chains of [[country:chile|Chile]] and Bolivia to the south and [[country:colombia|Colombia]]/[[country:ecuador|Ecuador]] to the north. The predominantly andesitic to dacitic magmas produce explosive eruptions, and several centers — notably [[volcano:huaynaputina|Huaynaputina]] — have generated Plinian eruptions with hemispheric climate impacts.

**Sabancaya** — [[volcano:sabancaya|Sabancaya]] is Peru's most currently active volcano, in near-continuous eruption since November 2016. Rising to 5,960 m (19,554 ft), it produces daily to weekly Vulcanian explosions with ash columns reaching 2–4 km above the crater. It has 12 confirmed eruptions and reached VEI 3 in both 1990 and 2016.

**Ubinas** — [[volcano:ubinas|Ubinas]] is Peru's most active volcano over historical timescales, with 25 confirmed eruptions. This truncated stratovolcano at 5,608 m (18,399 ft) features a 1.4-km-wide summit crater. Ubinas erupted in 2024, reached VEI 5 around 1082 CE, and poses persistent hazards to valley communities below.

**El Misti** — [[volcano:el-misti|El Misti]] is Peru's most iconic and potentially most dangerous volcano: a symmetrical stratovolcano at 5,793 m (19,006 ft) immediately northeast of Arequipa (~1 million people). With 15 confirmed eruptions including VEI 4 events, a significant eruption could generate pyroclastic flows, lahars, and ashfall across the entire metropolitan area.

**Huaynaputina** — [[volcano:huaynaputina|Huaynaputina]] ('New Volcano' in Quechua) produced the largest historical eruption in South America on February 19, 1600 — a VEI 6 Plinian event ejecting ~11 km³ of tephra. The eruption devastated southern Peru and injected enough sulfur dioxide into the stratosphere to contribute to global cooling; 1601 was among the coldest years of the past 600 years. Despite this extraordinary eruption, Huaynaputina lacks a prominent cone — it consists of a depression within an older amphitheater.

**Coropuna** — At 6,377 m (20,922 ft), [[volcano:coropuna|Coropuna]] is Peru's highest volcano and third-highest peak. This massive ice-capped complex covering 12 × 20 km has no confirmed historical eruptions but shows Holocene activity evidence.

**Tutupaca** — [[volcano:tutupaca|Tutupaca]] rises to 5,801 m (19,032 ft) and consists of two dissected edifices. Its last eruption occurred around 1802 at VEI 4, with a catastrophic sector collapse of the northern cone.

Peru's volcanic record includes 63 confirmed eruptions, dominated by the extraordinary VEI 6 eruption of [[volcano:huaynaputina|Huaynaputina]] in 1600 — the largest documented eruption in South American history and one of the most climatologically significant of the past millennium. The Plinian column reached 35+ km, pyroclastic flows devastated areas 12 km from the vent, and ashfall reached Lima over 1,000 km away. Global climate perturbation from stratospheric sulfate aerosols persisted 2–3 years.

[[volcano:ubinas|Ubinas]] has been Peru's most restless volcano, with a VEI 5 eruption around 1082 CE and modern eruptions in 2006–2009, 2013–2017, and 2023–2024. [[volcano:el-misti|El Misti]]'s record extends back thousands of years with VEI 4 events; geological studies reveal pyroclastic flows once reached the present site of Arequipa.

The VEI distribution for Peru shows 28 events at VEI 2, 7 at VEI 3, 2 at VEI 4, 2 at VEI 5, and 1 at VEI 6 — a system capable of extremely powerful eruptions despite modest frequencies. [[volcano:sabancaya|Sabancaya]]'s eruption since 2016 represents the longest sustained episode at any Peruvian volcano in modern times.

Peru's volcanic hazards are amplified by extreme altitudes, glacier ice on several summits, and El Misti's proximity to Arequipa. Pyroclastic flows from Misti, Ubinas, or Sabancaya could devastate communities in deep Andean valleys. Lahars from eruption-triggered glacier melt are a significant secondary hazard from ice-capped Coropuna and Misti.

Ashfall from Sabancaya's ongoing activity affects Colca Valley agriculture and occasionally disrupts air traffic at Arequipa's airport. A major El Misti eruption is the worst-case scenario: pyroclastic flows could reach Arequipa's outskirts within 20–30 minutes, and the city's water supply from Misti's rivers could be contaminated. Monitoring is led by the OVI in Arequipa and the IGP in Lima, operating seismic networks, satellite surveillance, and gas measurement systems.

Peru's 13 Holocene volcanoes occupy a compact zone in the far south, stretching ~450 km from Quimsachata-Oroscocha (14.1°S) near Cusco to Nevados Casiri (17.5°S) near the Chilean border. All lie within the departments of Arequipa, Moquegua, Tacna, and Puno along the Western Cordillera. The highest concentration is in the Arequipa region, where Sabancaya, El Misti, Ubinas, and Huaynaputina cluster within 150 km.

The arc continues seamlessly into [[country:chile|Chile's]] Northern Volcanic Zone to the south.

Volcanoes are deeply embedded in Peruvian culture, stretching back to pre-Inca civilizations. The Inca regarded volcanoes as sacred beings (apus), and the discovery of the 'Ice Maiden' Juanita near Ampato's summit revealed the ritual significance of volcanic peaks. El Misti dominates Arequipa's skyline and is central to the city's identity — 'La Ciudad Blanca' refers partly to the white sillar volcanic rock used in its UNESCO Heritage colonial architecture.

Volcanic soils support Colca Valley agriculture, though Sabancaya's ashfall periodically damages crops. The Colca Valley — famed for condor viewing and one of the world's deepest canyons — is carved through volcanic deposits. Geothermal hot springs attract visitors throughout the region.

Southern Peru offers spectacular volcanic tourism. The Colca Valley provides views of [[volcano:sabancaya|Sabancaya]]'s eruption plume. Multi-day climbs of El Misti (5,793 m, typically 2 days) and Chachani (6,057 m) are popular mountaineering objectives requiring altitude acclimatization.

The Andahua Valley of the Volcanoes offers a unique landscape of cinder cones. Sabancaya's ashfall can affect Colca area air quality, and Misti access may be restricted during elevated seismicity. The dry season (May–October) provides the best conditions.