Agua de Pau

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  • 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) Cite 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 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 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) Cite 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 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 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.

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude
382090

1564 CE

947 m / 3106 ft

37.77°N
25.47°W

Volcano Types

Stratovolcano
Caldera(s)
Lava dome(s)
Pyroclastic cone(s)

Rock Types

Major
Trachyte / Trachyandesite
Trachybasalt / Tephrite Basanite
Basalt / Picro-Basalt
Trachyandesite / Basaltic trachy-andesite

Tectonic Setting

Rift zone
Oceanic crust (< 15 km)

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
406
17,272
113,131
119,653

Geological Summary

Agua de Pau stratovolcano in central Sao Miguel Island contains an outer 4 x 7 km caldera formed about 30,000 to 45,000 years ago and an inner 2.5 x 3 km caldera that was created about 15,000 years ago. The younger caldera is partially filled by the Lagoa do Fogo caldera lake. Several post-caldera lava domes were emplaced on the northern and western flanks of the volcano, but activity in the caldera did not resume until about 5000 years ago. The 3-cu-km Fogo-A plinian pumice-fall deposit, the product of the largest-known Holocene eruption in the Azores, was emplaced at this time. Numerous flank cinder cones mark radial and concentric fissures, some of which have been active during historical time. The latest trachytic explosive eruption took place during 1563. Prominent hot springs are located on the NW flank.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Booth B, Croasdale R, Walker G P L, 1978. A quantitative study of five thousand years of volcanism on Sao Miguel, Azores. Phil Trans Roy Soc London, Ser A, 288: 271-319.

Capaccioni B, Forjaz V H, Martini M, 1994. Pyroclastic flow hazard at Agua de Pau volcano (Sao Miguel Island, Azores archipelago) inferred from the Fogo A eruptive unit. Acta Vulc, 5: 41-48.

Martins J A, 1982. Excursion guide for field trip V1, Island of Sao Miguel. Proc Internatl Symp Activity Oceanic Volc, Archipelago Univ Azores, 3: 315-328.

Moore R B, 1983b. Preliminary geologic map of Furnas volcano, Sao Miguel, Azores (1:15,000). U S Geol Surv Open-File Rpt, 83-395.

Moore R B, 1986. Preliminary geologic map of Agua de Pau volcano, Sao Miguel, Azores. U S Geol Surv Open-File Rpt, 86-192.

Moore R B, 1990. Volcanic geology and eruption frequency, Sao Miguel, Azores. Bull Volc, 52: 602-614.

Moore R B, 1991. Geologic map of Sao Miguel, Azores. U S Geol Surv Map, I-2007.

Neumann van Padang M, Richards A F, Machado F, Bravo T, Baker P E, Le Maitre R W, 1967. Atlantic Ocean. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 21: 1-128.

Zbyszewski G, Moitinho de Almeida F, Veiga Ferreira O da, Torre de Assuncao C, 1958. Geologic map of Sao Miguel (Azores). Servicos Geologicos Portugal, two 1:50,000 scale maps with 22 and 37 p texts (in Portuguese).

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.


Synonyms

Vulcao de Lagoa do Fogo | Fogo

Cones

Feature Name Feature Type Elevation Latitude Longitude
Escuro, Monte Cone 889 m 35° 47' 0" N 25° 26' 0" W
Joao Fernandes, Pico Cone 386 m 35° 46' 0" N 25° 33' 0" W
Mariana, Pico da Cone 445 m 35° 45' 0" N 25° 31' 0" W
Mos Cone 358 m 37° 46' 0" N 25° 33' 0" W
Vermelho, Pico Cone 269 m 35° 48' 0" N 25° 30' 0" W

Craters

Feature Name Feature Type Elevation Latitude Longitude
Congro, Lagoa do Maar 569 m 35° 45' 0" N 25° 25' 0" W
Fogo, Lagoa do Pleistocene caldera 948 m 35° 46' 0" N 25° 28' 0" W
San Bras, Lagoa de Maar 711 m 35° 48' 0" N 25° 25' 0" W

Domes

Feature Name Feature Type Elevation Latitude Longitude
Altinetes, Pico Dome 226 m 37° 48' 0" N 25° 33' 0" W
Barnabe, Pico Dome 213 m 37° 48' 0" N 25° 33' 0" W
Cerrado Novo Dome 532 m 35° 48' 0" N 25° 27' 0" W
Cintrao Dome 166 m 35° 50' 0" N 25° 29' 0" W
Queimado, Cerro Dome 347 m 37° 47' 0" N 25° 33' 0" W

Thermal

Feature Name Feature Type Elevation Latitude Longitude
Velha, Caldeira Thermal

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).
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).
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).
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).
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).

Smithsonian Sample Collections Database


A listing of samples from the Smithsonian collections will be available soon.

Affiliated Sites

Large Eruptions of Agua de Pau Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
MODVOLC - HIGP MODIS Thermal Alert System Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.
MIROVA Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.