Agua de Pau

Photo of this volcano
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 37.77°N
  • 25.47°W

  • 947 m
    3106 ft

  • 382090
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

Most Recent Bulletin Report: March 1989 (SEAN 14:03) Citation IconCite this Report


Seismicity since May 1988 summarized

[Agua de Pau information only; extracted from a summary of significant seismic activity in the E Azores (figure 1) since May 1988.]

Figure (see Caption) Figure 1. Sketch map showing islands in the eastern Azores. Approximate epicenters of the 3-5 October 1988 swarm at the submarine volcano Don Joao de Castro Bank (4) and the 21 November 1988 and 21 January 1989 earthquakes in the Hirondelle Basin (6 and 7) are shown. Courtesy of R. Moore.

"A swarm of microearthquakes, accompanied by weak harmonic tremor, occurred beneath the NE flank of Agua de Pau Volcano on Sao Miguel (figure 2, zone 1) 23-24 May 1988. Seismometers recorded 383 earthquakes; the largest had intensities of MM IV-V in villages along the N coast. A similar but smaller swarm occurred in the same area in 1983 and was recorded by USGS seismographs. Numerous, small, normal faults (including some that show scissor-type movement) displace basaltic, tristanitic, and trachytic vent deposits and flows in this area. However, the area has had no eruptions for about 3,000 years and is the least active of the five volcanic zones on Sao Miguel that have erupted during Holocene time.

Figure (see Caption) Figure 2. Approximate epicenters for earthquakes on and near the island of Sao Miguel, May-October, 1988. Courtesy of R. Moore.

"A small swarm of microearthquakes occurred 24-26 June [1988] on the S flank of Agua de Pau Volcano (zone 2). Sixty-four earthquakes were recorded; the largest had intensities of MM III-IV in nearby villages. No tremor accompanied this episode.

"A small swarm of microearthquakes occurred 6 July [1988] near the S coast of Sao Miguel (zone 3). Fifty-one earthquakes were recorded; the largest was felt and had an intensity of MM III-IV. No tremor accompanied this episode.

Information Contacts: A. Rodrigues da Silva, Consorcio Geotermico de S. Miguel; R. Moore, USGS; National Institute of Meteorology and Geophysics, Portugal.

The Global Volcanism Program has no Weekly Reports available for Agua de Pau.

Bulletin Reports - Index


Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

03/1989 (SEAN 14:03) Seismicity since May 1988 summarized




Information is preliminary and subject to change. All times are local (unless otherwise noted)


March 1989 (SEAN 14:03) Citation IconCite this Report


Seismicity since May 1988 summarized

[Agua de Pau information only; extracted from a summary of significant seismic activity in the E Azores (figure 1) since May 1988.]

Figure (see Caption) Figure 1. Sketch map showing islands in the eastern Azores. Approximate epicenters of the 3-5 October 1988 swarm at the submarine volcano Don Joao de Castro Bank (4) and the 21 November 1988 and 21 January 1989 earthquakes in the Hirondelle Basin (6 and 7) are shown. Courtesy of R. Moore.

"A swarm of microearthquakes, accompanied by weak harmonic tremor, occurred beneath the NE flank of Agua de Pau Volcano on Sao Miguel (figure 2, zone 1) 23-24 May 1988. Seismometers recorded 383 earthquakes; the largest had intensities of MM IV-V in villages along the N coast. A similar but smaller swarm occurred in the same area in 1983 and was recorded by USGS seismographs. Numerous, small, normal faults (including some that show scissor-type movement) displace basaltic, tristanitic, and trachytic vent deposits and flows in this area. However, the area has had no eruptions for about 3,000 years and is the least active of the five volcanic zones on Sao Miguel that have erupted during Holocene time.

Figure (see Caption) Figure 2. Approximate epicenters for earthquakes on and near the island of Sao Miguel, May-October, 1988. Courtesy of R. Moore.

"A small swarm of microearthquakes occurred 24-26 June [1988] on the S flank of Agua de Pau Volcano (zone 2). Sixty-four earthquakes were recorded; the largest had intensities of MM III-IV in nearby villages. No tremor accompanied this episode.

"A small swarm of microearthquakes occurred 6 July [1988] near the S coast of Sao Miguel (zone 3). Fifty-one earthquakes were recorded; the largest was felt and had an intensity of MM III-IV. No tremor accompanied this episode.

Information Contacts: A. Rodrigues da Silva, Consorcio Geotermico de S. Miguel; R. Moore, USGS; National Institute of Meteorology and Geophysics, Portugal.

Eruptive History


Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).


Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1564 Feb 10 1564 Feb 12 Confirmed 2 Historical Observations Lagoa do Fogo caldera
1563 Jun 28 1563 Jul 26 ± 5 days Confirmed 5 Historical Observations Caldera, NW flank (Cerro Queimado)
0700 ± 150 years Unknown Confirmed   Radiocarbon (uncorrected) WNW flank (Mos)
0160 ± 150 years Unknown Confirmed   Radiocarbon (uncorrected) NW flank (251 m)
1290 BCE (?) Unknown Confirmed 4 Radiocarbon (uncorrected) Lagoa do Fogo caldera
1850 BCE ± 500 years Unknown Confirmed 3 Radiocarbon (uncorrected) East flank (Lagoa do Congro)
2210 BCE ± 150 years Unknown Confirmed   Radiocarbon (uncorrected) East flank (East Congo maar)
2990 BCE (?) Unknown Confirmed 5 Radiocarbon (uncorrected) Lagoa do Fogo caldera and north flank
4550 BCE ± 100 years Unknown Confirmed   Radiocarbon (uncorrected) SW flank (449 m)
6750 BCE ± 200 years Unknown Confirmed   Radiocarbon (uncorrected) West flank (Pico Joao Fernandes)

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Photo Gallery


The inner Agua de Pau caldera, seen here from the western caldera rim, is now partially filled by Lagoa do Fogo caldera lake. The caldera was the source of a major explosive eruption about 5000 years ago. This eruption produced tephra layer Fogo A, which marked the renewal of major explosive activity within the 15,000-year-old inner Agua de Pau caldera. The eruption produced pyroclastic flows and thick mudflows that reached the northern and southern coasts of Sao Miguel Island.

Photo by Rick Wunderman, 1997 (Smithsonian Institution).
See title for photo information.
Lagoa do Fogo ("Fire Lake") appears to occupy a line of craters possibly dating from a major eruption during 1563. A plinian eruption from the central caldera began on June 28, 1563, depositing trachytic pumice eastward over the island. On July 2, a NW-flank effusive eruption began, which lasted until the end of July and produced a lava flow that reached the northern coast at Ribeira Grande.

Photo by Rick Wunderman, 1997 (Smithsonian Institution).
See title for photo information.
Lagoa do Fogo lake, seen here from the west, partially fills the younger of two Pleistocene calderas on Agua de Pau stratovolcano in central Sao Miguel Island. Several post-caldera lava domes were emplaced on the northern and western flanks of the volcano, but activity inside the caldera did not resume until the eruption of the 5000-year-old Fogo-A plinian pumice-fall deposit, the product of the largest-known Holocene eruption in the Azores. Numerous cinder cones have erupted on the flanks of Agua de Pau during historical time.

Photo by Rick Wunderman, 1977 (Smithsonian Institution).
See title for photo information.
The forested ridge in the center of the photo is part of the northern rim of the 2.5 x 3 km inner Agua de Pau caldera. The Serra de Agua de Pau hills in the background mark the northern rim of an outer 4 x 7 km caldera of Pleistocene age, which formed approximately 33,000 years ago. Lagoa de Fogo caldera lake (lower right) partially fills the inner caldera.

Photo by Rick Wunderman, 1997 (Smithsonian Institution).
See title for photo information.
A public fountain at Ribeira Grande on the northern coast of San Miguel Island was buried by a lava flow that was erupted from Agua de Pau volcano in 1563. The fountain had been constructed sometime during the half century prior to the 1563 eruption. The lava flow, which originated on July 2 from a vent of the NW flank of Cerro Queimado, remained active until the end of the month. It was preceded by a major plinian eruption from the central caldera that began on June 28 and deposited trachytic pumice eastward over the island.

Photo by Rick Wunderman, 1997 (Smithsonian Institution).
See title for photo information.

Smithsonian Sample Collections Database


There are no samples for Agua de Pau in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

Affiliated Sites