🌋VolcanoAtlas

Agua de Pau

The Lake of Fire Volcano

Elevation

947 m

Last Eruption

1564

Type

Stratovolcano

Country

Portugal

Location

Loading map...

Volcanic Hazards & Risk Assessment

Primary Hazards

  • Pyroclastic flows
  • Lava flows
  • Volcanic bombs and ballistics
  • Lahars and mudflows

Risk Level

Population at RiskLow
Infrastructure RiskModerate
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

MetricValueGlobal RankingSignificance
Total Recorded EruptionsUnknownLowModerately active volcano
Maximum VEIVEI UnknownMinorLocal impact potential
Recent Activity462 years agoHistoricalHistorically active

Monitoring & Alert Status

Monitoring Networks

Global Volcanism Program
International eruption database

Current Status

Normal
No recent activity. Routine monitoring continues.

Authority Sources

Smithsonian GVP
Official volcano database

Related Volcanoes

All Portugal Volcanoes
Explore by country
Stratovolcano Volcanoes
By volcano type
Azores, São Miguel Island
Regional volcanoes

Other Volcanoes in Portugal

Interesting Facts

🌋

Agua de Pau is the tallest point on São Miguel Island at 947 m (3,107 ft), towering above both Sete Cidades (842 m) and Furnas (805 m).

🌋

The Fogo-A eruption around 2990 BCE deposited approximately 3 km³ of trachytic pumice, making it one of the largest Holocene eruptions in the entire Azores archipelago.

🌋

Agua de Pau has a double caldera — an outer one 4 × 7 km formed 30,000–45,000 years ago, and an inner one 2.5 × 3 km created about 15,000 years ago.

🌋

Lagoa do Fogo ('Lake of Fire') fills the inner caldera and is one of the most pristine volcanic crater lakes in Europe, protected as a nature reserve since 1974.

🌋

The 1563 eruption was the most devastating volcanic event in São Miguel's recorded history, producing a Plinian column, pyroclastic flows, and thick pumice falls that buried central São Miguel.

🌋

Hot springs at Caldeira Velha on the northwest flank discharge water at temperatures exceeding 90°C, confirming ongoing magmatic heat input beneath the volcano.

🌋

Agua de Pau sits on the narrowest section of São Miguel, where the island is only 8 km wide, placing populations on both coasts within direct hazard range.

🌋

The 460-year repose since 1564 is the longest gap in Agua de Pau's documented eruption history, but consistent with an average recurrence interval of roughly 875 years.

🌋

Two of Agua de Pau's 10 recorded eruptions reached VEI 5 — the same explosive magnitude as Mount Vesuvius's legendary 79 AD eruption.

🌋

The Lagoa do Fogo crater lake's water volume represents a significant secondary hazard: interaction between erupting magma and lake water could generate violent phreatomagmatic explosions and lahars.

Frequently Asked Questions

Is Agua de Pau still active?
Yes, Agua de Pau is classified as an active volcano despite not having erupted since 1564. The 460-year repose is consistent with its historical eruption frequency (average interval of roughly 875 years between events). Active hydrothermal features, including the Caldeira Velha hot springs on the northwest flank and diffuse CO₂ degassing from the caldera, confirm an active magmatic system. CIVISA monitors the volcano continuously. Volcanologists consider a future eruption certain on geological timescales.
What happened during the 1563 eruption?
The 1563 eruption was a VEI 5 Plinian event — the most destructive volcanic disaster in São Miguel's recorded history. It began in late June with a massive explosive phase from the caldera, generating a towering eruption column and depositing thick trachytic pumice across central São Miguel. Pyroclastic flows swept down the flanks, and a lava dome was extruded at Cerro Queimado on the northwest flank. Towns on both the north and south coasts suffered severe ashfall, agricultural devastation, and casualties. A smaller VEI 2 eruption followed in 1564.
Can you visit Lagoa do Fogo?
Yes, Lagoa do Fogo is one of São Miguel's top natural attractions. The lake is accessible via a well-maintained hiking trail from the EN5-2A road on the caldera rim, taking approximately 45 minutes to descend to the lakeshore. The trail is of moderate difficulty. Swimming is permitted but the water is cold year-round. The caldera rim road offers several scenic viewpoints even without hiking. The nearby Caldeira Velha hot springs provide a warm geothermal bathing experience in a lush forest setting.
How does Agua de Pau compare to Sete Cidades?
Both are active stratovolcanoes with calderas on São Miguel Island, but they differ significantly. Agua de Pau is taller (947 m vs 842 m), has produced larger eruptions (VEI 5 vs VEI 4 maximum), and has a double caldera system. Sete Cidades has more total recorded eruptions (16 vs 10) and erupted more recently (1880 vs 1564). Sete Cidades is best known for its twin-colored lakes, while Agua de Pau is known for the pristine Lagoa do Fogo. Both volcanoes are monitored by CIVISA and are considered potentially dangerous.
How tall is Agua de Pau?
Agua de Pau reaches 947 m (3,107 ft) above sea level, making it the highest point on São Miguel Island. The inner caldera containing Lagoa do Fogo sits at approximately 575 m elevation. For comparison, the other two major volcanoes on São Miguel — Sete Cidades and Furnas — reach 842 m and 805 m respectively. Agua de Pau's elevation, combined with its position on the island's central spine, makes it a dominant topographic feature visible from both the north and south coasts.
What is the danger of Agua de Pau erupting?
Agua de Pau is considered the most hazardous volcano in the Azores due to its proven capacity for VEI 5 Plinian eruptions and its position on São Miguel's narrowest isthmus (only 8 km wide). A major eruption could produce pyroclastic flows reaching both coasts, thick pumice falls collapsing buildings, and lahars from interaction with Lagoa do Fogo's water. Approximately 30,000 people live within the primary hazard zone. Ashfall could disrupt Atlantic air traffic and affect all of São Miguel's 140,000 residents.