Agua de Pau (Portugal): Recorded Eruptions and Historical Activity

Agua de Pau is a stratovolcano located in Portugal, standing at an elevation of 947 meters with a tectonic setting characterized by a rift zone and oceanic crust less than 15 kilometers deep. According to the Smithsonian Global Volcanism Program, the volcano has a confirmed record of 10 eruptions spanning from deep prehistory into the 16th century CE.

The historical and prehistoric record demonstrates activity across different flanks and summit areas, documented through a combination of isotopic dating methods—such as uncalibrated radiocarbon dating—and direct historical observations.

Overview of Recorded Eruptions

The confirmed eruption record for Agua de Pau contains 10 events, with the earliest recorded activity dating back to approximately 6750 BCE with an uncertainty of 200 years on the start year. The largest recorded eruption reached a Volcanic Explosivity Index (VEI) of 5.0. Out of the 10 confirmed eruptions, 5 have recorded VEI classifications.

Representative events within the official record illustrate the variety of activity areas and evidence methods:

• 6750 BCE: An eruption occurred on the west flank at Pico Joao Fernandes, evidenced by uncalibrated radiocarbon isotopic methods.
• 2990 BCE: A large eruption with a VEI of 5.0 took place at the Lagoa do Fogo caldera and north flank.
• 1850 BCE: Activity occurred on the east flank at Lagoa do Congro, with a VEI of 3.0 and a start year uncertainty of 500 years.
• 1563 CE: A VEI 5.0 eruption occurred between June 28, 1563, and July 26, 1563, affecting the caldera and the northwest flank at Cerro Queimado, documented by reported observations.
• 1564 CE: A final recorded eruption took place in the Lagoa do Fogo caldera between February 10, 1564, and February 12, 1564, with a VEI of 2.0 based on reported observations.

Chronological Distribution by Century

Confirmed eruptions at Agua de Pau are distributed across multiple centuries of activity ranging from the 68th century BCE to the 16th century CE:

• 68th century BCE: 1 eruption
• 46th century BCE: 1 eruption
• 30th century BCE: 1 eruption
• 23rd century BCE: 1 eruption
• 19th century BCE: 1 eruption
• 13th century BCE: 1 eruption
• 2nd century CE: 1 eruption
• 7th century CE: 1 eruption
• 16th century CE: 2 eruptions

The latest recorded eruption in the official database started on February 10, 1564, and concluded on February 12, 1564. The last known eruption year listed in the volcano profile is 1564.