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Sete Cidades Massif

Sete Cidades

Stratovulcano · Portugal · 842 m

A small peninsula extends into Lagoa Azul ("Blue Lake"), one of two main lakes partially filling the floor of the summit caldera on Sete Cidades volcano at the western end of Sao Miguel Island. The 5-km-wide caldera was formed in three major eruptions at about 36,000, 29,000 and 16,000 years ago, and at least 17 eruptions have occurred here in the last 5,000 years. This view looks to the northwest from the rim of a post-caldera cone containing Lagoa Santiago. Two other post-caldera cones, Caldeira do Alferes and Seara, lie across the lake, behind and to the right of the town of Sete Cidades.
A small peninsula extends into Lagoa Azul ("Blue Lake"), one of two main lakes partially filling the floor of the summit caldera on Sete Cidades volcano at the western end of Sao Miguel Island. The 5-km-wide caldera was formed in three major eruptions at about 36,000, 29,000 and 16,000 years ago, and at least 17 eruptions have occurred here in the last 5,000 years. This view looks to the northwest from the rim of a post-caldera cone containing Lagoa Santiago. Two other post-caldera cones, Caldeira do Alferes and Seara, lie across the lake, behind and to the right of the town of Sete Cidades. · Foto: Photo by R.V. Fisher, 1980 (University of California Santa Barbara). · Wikimedia Commons
Tipo
Stratovulcano
Paese
Portugal
Regione
Atlantic Ocean Volcanic Regions / Azores-Terceira Rift Volcanic Province
Altitudine
842 m
Coordinate
37.865, -25.785
Ultima eruzione
1880
Contesto tettonico
Rift zone / Oceanic crust (< 15 km)
Forma vulcanica
Composite
Roccia principale
Trachyte / Trachydacite
Sintesi geologica

Sete Cidades volcano at the western end of Sao Miguel Island contains a 5-km-wide summit caldera occupied by two caldera lakes. The steep-walled, 500-m-deep caldera was formed about 22,000 years ago, and at least 22 post-caldera eruptions have occurred. A large group of Pleistocene post-caldera trachytic lava domes, lava flows, and pyroclastic-flow deposits is found on the western-to-northern flanks. A nearly circular ring of six Holocene pyroclastic cones on the caldera floor have been the source of a dozen trachytic pumice-fall deposits erupted during the past 5,000 years. Recorded eruptions date back to the 15th century and have occurred both within the caldera and from submarine vents off the west coast.

Sintesi da Wikipedia

Riassunto in inglese

Sete Cidades Massif is a stratovolcanic complex, referring to a polygenetic volcano and caldera, located in western part of the island of São Miguel, in the Portuguese archipelago of the Azores. More recognizable for the Lagoa das Sete Cidades at its centre, the volcanic complex includes centuries of geomorphological structures that include lava domes, cones, lava flows and maar geomorphology that have marked its history.

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Storia delle eruzioni

Riepilogo (VEI nel tempo)
Fai clic su una barra per vedere le singole eruzioni
3050 BCE~2853 BCE · 1 eruzioni · VEI max. 42064 BCE~1867 BCE · 1 eruzioni · VEI max. ?881 BCE~684 BCE · 1 eruzioni · VEI max. ?92 BCE~105 · 1 eruzioni · VEI max. 4302~500 · 1 eruzioni · VEI max. 4500~697 · 1 eruzioni · VEI max. 3894~1091 · 1 eruzioni · VEI max. 21091~1288 · 1 eruzioni · VEI max. 21288~1486 · 1 eruzioni · VEI max. 41486~1683 · 2 eruzioni · VEI max. 21683~1880 · 5 eruzioni · VEI max. 33050 BCE1867 BCE684 BCE5001683

Cronologia dettagliata

  1. 1880VEI 0Stima geologica
    1880 – In corso
    Volcano Uncertain: submarine vent off Sao Miguel
  2. 1861VEI 0Stima geologica
    1861 – In corso
    Volcano Uncertain: submarine vent off Sao Miguel
  3. 1811VEI 2Osservata
    1811-02-01 – 1811-02-08
    Submarine vent west of Sete Cidades
  4. 1811VEI 3Osservata
    1811-06-14 – 1811-06-22
    Submarine vent west of Sete Cidades
  5. 1713VEI 2Osservata
    1713 – In corso
    West flank (Pico das Camarinhas)
  6. 1682VEI 2Osservata
    1682-12-13 – In corso
    Submarine vent west of Sete Cidades
  7. 1638VEI 2Osservata
    1638-07-03 – 1638-07-28
    Submarine vent west of Sete Cidades
  8. 1444VEI 4Osservata
    1444 – In corso
    SW side of caldera (Caldeira Seca)
  9. 1110 (±50 anni)VEI 2Stima geologica
    1110 – In corso
    West flank (Ponta de Ferraria)
  10. 950 (±100 anni)VEI 2Stima geologica
    950 – In corso
    SE flank (Ferraria)
  11. 670 (±150 anni)VEI 3Stima geologica
    670 – In corso
    SE flank (Carvao)
  12. 380 (±300 anni)VEI 4Stima geologica
    380 – In corso
    SE caldera floor (Lagoa Rasa)
  13. 90 (±100 anni)VEI 4Stima geologica
    90 – In corso
    SE caldera floor (Lagoa de Santiago)
  14. 750 a.C. (±300 anni)VEI ?Stima geologica
    BCE 750 – In corso
    SE flank (Eguas)
  15. 2050 a.C. (±1000 anni)VEI ?Stima geologica
    BCE 2050 – In corso
    Caldeira do Alfreres and NW flank
  16. 3050 a.C.VEI 4Stima geologica
    BCE 3050 – In corso
    Seara Cerrado da Ladeira

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