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  • Portugal
  • Azores
  • Stratovolcano
  • 1630 CE
  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 37.77°N
  • 25.32°W

  • 805 m
    2640 ft

  • 382100
  • Latitude
  • Longitude

  • Summit

  • Volcano

There are no activity reports for Furnas.

 Available Weekly Reports

There are no Weekly Reports available for Furnas.

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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1630 Sep 3 1630 Nov 2 Confirmed 5 Historical Observations South end of caldera (Pico da Areia)
1441 ± 2 years Unknown Confirmed 4 Historical Observations Center of caldera (Gaspar), Tephra layer I
1430 ± 100 years Unknown Confirmed 3 Radiocarbon (uncorrected) East caldera floor, Tephra layer H
1170 ± 100 years Unknown Confirmed 4 Radiocarbon (uncorrected) E caldera floor (Lake crater), Tephra layer G
0840 ± 100 years Unknown Confirmed 4 Radiocarbon (uncorrected) Center of caldera (Gaspar), Tephra layer F
0080 ± 100 years Unknown Confirmed 5 Radiocarbon (uncorrected) N floor of younger caldera, Tephra layer C
0360 BCE ± 150 years Unknown Confirmed   Radiocarbon (uncorrected) Tephra layer B
1670 BCE ± 1000 years Unknown Confirmed   Tephrochronology Tephra layer A
4570 BCE (in or before) Unknown Confirmed   Radiocarbon (uncorrected) East rim of caldera (Pico do Canário)

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

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.

Cole P D, Guest J E, Queiroz G, Wallenstein N, Pacheco J-M, Gaspar J L, Ferreira T, Duncan A M, 1999. Styles of volcanism and volcanic hazards on Furnas volcano, Sao Miguel, Azores. J Volc Geotherm Res, 92: 39-53.

Cole P D, Queiroz G, Wallenstein N, Gaspar J L, Duncan A M, Guest J E, 1995. A historic subplinian/phreatomagmatic eruption: the 1630 AD eruption of Furnas volcano, Sao Miguel, Azores. J Volc Geotherm Res, 69: 117-135.

Duncan A M, Queiroz G, Guest J E, Cole P D, Wallenstein N, Pacheco J M, 1999. The Povoacao Ignimbrite, Furnas volcano, Sao Miguel, Azores. J Volc Geotherm Res, 92: 55-65.

Ferreira T, Oskarsson N, 1999. Chemistry and isotopic composition of fumarole discharges of Furnas caldera. J Volc Geotherm Res, 92: 169-179.

Guest J E, Gaspar J L, Cole P D, Queiroz G, Duncan A M, Wallenstein N, Ferreira T, Pacheco J-M, 1999. Volcanic geology of Furnas volcano, Sao Miguel, Azores. J Volc Geotherm Res, 92: 1-29.

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, 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.

Newhall C G, Dzurisin D, 1988. Historical unrest at large calderas of the world. U S Geol Surv Bull, 1855: 1108 p, 2 vol.

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).

Furnas volcano lies at the eastern end of Sao Miguel Island, immediately west of the older Nordeste shield volcano and its Povoaçao caldera. Furnas contains at least two calderas, a younger one that is 6-km wide and a larger older one that is less topographically distinct. The eastern wall of the 500-m-deep caldera of Furnas overlaps the western wall of the Povoaçao caldera of Nordeste volcano. Volcanic activity at Furnas dates back about 100,000 years. At least 11 trachytic pumice layers, all erupted during the past 5000 years, post-date the caldera. The most prominent post-caldera feature is the Pico do Gaspar lava dome, east of the Lagoa das Furnas caldera lake. A zone of late-Pleistocene to Holocene basaltic-to-trachytic cinder cones and lava domes is located between Furnas and Agua de Pau volcanoes. Two historical eruptions have occurred at Furnas, one sometime between 1439 and 1443 and the other in 1630. The latter was one of the largest Holocene explosive eruptions in the Azores and caused significant damage and fatalities.