Cerro Blanco

South America's Hidden Supervolcano

Elevation

4,670 m

Last Eruption

~2300 BCE

Type

Caldera

Country

Argentina

Location

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Volcanic Hazards & Risk Assessment

Primary Hazards

Pyroclastic flows and surges
Large explosive eruptions (VEI 4+)
Ash fall and tephra deposits
Lahars and debris flows

Risk Level

Population at RiskLow

Infrastructure RiskHigh

Aviation RiskSignificant

Geological Composition & Structure

Rock Types

Primary

Unknown

Silica Content

Varied composition

Tectonic Setting

Unknown

Intraplate setting with hotspot or regional volcanic activity.

Age & Formation

Epoch

Unknown

Evidence

Unknown

Eruption Statistics & Analysis

Metric	Value	Global Ranking	Significance
Total Recorded Eruptions	Unknown	Low	Moderately active volcano
Maximum VEI	VEI Unknown	Minor	Local impact potential
Recent Activity	-274 years ago	Very Recent	Currently active

Monitoring & Alert Status

Monitoring Networks

Global Volcanism Program

International eruption database

Current Status

Active

Recent volcanic activity detected. Continuous monitoring in place.

Authority Sources

Smithsonian GVP

Official volcano database

Related Volcanoes

All Argentina Volcanoes

Explore by country

Caldera Volcanoes

By volcano type

Southern Puna, Catamarca Province

Regional volcanoes

Interesting Facts

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Cerro Blanco's ~4,200 BP eruption ejected over 170 km³ of tephra — roughly double the volume of the 1815 Tambora eruption.

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The eruption column reached approximately 32 km into the stratosphere, according to computer simulations.

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Ash from the eruption was dispersed across approximately 500,000 km² — an area larger than Spain.

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Tephra deposits have been found 400 km from the caldera, near Santiago del Estero in central Argentina.

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The Cerro Blanco eruption is classified as VEI 7, the same magnitude as the Minoan eruption of Santorini that destroyed Bronze Age Cretan civilization.

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Satellite surveys in the 1990s detected the caldera subsiding at 2–2.5 cm/year, indicating ongoing geological activity.

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The Robledo caldera (5 km diameter) is the youngest known caldera in the Central Andes.

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Cerro Blanco remains unmonitored — no seismometers, GPS stations, or gas sensors exist at the site.

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The eruption produced the Campo de la Piedra Pómez — a vast field of white pumice sculpted by wind into formations studied as Mars surface analogues.

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Archaeological evidence suggests the eruption contributed to depopulation of the Fiambalá region for centuries.

Frequently Asked Questions

How big was the Cerro Blanco eruption?

The Cerro Blanco eruption approximately 4,200 years ago was a VEI 7 event — one of the largest volcanic eruptions of the Holocene (past 11,700 years). It ejected more than 170 km³ of tephra across 500,000 km², with the eruption column reaching approximately 32 km altitude. The erupted magma volume (~83 km³ DRE) was roughly double that of Tambora's 1815 eruption and comparable to the Minoan eruption of Santorini. It is the largest known Holocene eruption in the Central Andes.

Is Cerro Blanco still active?

Cerro Blanco is classified as dormant rather than extinct. Although its only documented eruption occurred ~4,200 years ago, satellite radar surveys detected ongoing caldera subsidence at 2–2.5 cm/year in the 1990s, indicating active geological processes at depth. The volcano is currently unmonitored due to its extreme remoteness. While a near-term eruption is considered unlikely, the volcano cannot be ruled out as a future hazard given its VEI 7 capability.

Could Cerro Blanco erupt again?

Future eruptions at Cerro Blanco are possible, though timing is unpredictable. The ongoing caldera subsidence detected by satellite suggests active processes. Future activity might involve dome-building eruptions or smaller Plinian events rather than a full VEI 7 repeat. Given the sparse population, the primary impact of a future eruption would come from stratospheric ash injection affecting climate and air traffic. The volcano's unmonitored status is a concern.

Where is Cerro Blanco?

Cerro Blanco is located in Catamarca Province, northwestern Argentina, on the southern Puna plateau at 26.77°S, 67.75°W. It sits at approximately 4,670 m elevation, roughly 80 km southwest of the Cerro Galán caldera. The nearest town is Antofagasta de la Sierra (~80 km northeast). The region is extremely remote and hyperarid.

Is Cerro Blanco a supervolcano?

Cerro Blanco's VEI 7 eruption places it at the boundary between 'super-colossal' and 'supervolcanic' events (VEI 8 is the threshold for supervolcano status). While not technically a supervolcano, its ~170 km³ tephra output ranks among the largest Holocene eruptions globally. The eruption was comparable to events at confirmed supervolcanic systems like Santorini and Crater Lake (Mazama).

Can you visit Cerro Blanco?

Cerro Blanco is accessible only by off-road vehicle from Antofagasta de la Sierra (6–8 hours from Catamarca city). There are no facilities or maintained trails. The nearby Campo de la Piedra Pómez pumice field is a growing tourist attraction, reachable on guided 4×4 excursions. Visitors must prepare for extreme altitude (4,600+ m), intense UV, temperature extremes, and complete self-sufficiency.