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Sierra Negra

Negra, Sierra

Vulcano a scudo · Ecuador · 1124 m

An aerial view of the SW caldera floor of Sierra Negra volcano shows El Azufre fumarolic field and the trap-door fault to the left. This sinuous 14-km-long, N-S-trending ridge occupies the west part of the caldera floor, which lies only about 100 m below its rim. El Azufre, the largest fumarolic area in the Galápagos Islands, lies within a graben between this ridge and the west caldera wall. The broad shield volcano of Sierra Negra at the southern end of Isabela Island contains a shallow 7 x 10.5 km caldera that is the largest in the Galápagos Islands.
An aerial view of the SW caldera floor of Sierra Negra volcano shows El Azufre fumarolic field and the trap-door fault to the left. This sinuous 14-km-long, N-S-trending ridge occupies the west part of the caldera floor, which lies only about 100 m below its rim. El Azufre, the largest fumarolic area in the Galápagos Islands, lies within a graben between this ridge and the west caldera wall. The broad shield volcano of Sierra Negra at the southern end of Isabela Island contains a shallow 7 x 10.5 km caldera that is the largest in the Galápagos Islands. · Foto: Photo by Patricio Ramon, 2005 (Instituto Geofisca, Escuela Politecnica Nacional). · Wikimedia Commons
Tipo
Vulcano a scudo
Paese
Ecuador
Regione
Eastern Pacific Volcanic Regions / Galapagos Hotspot Volcano Group
Altitudine
1124 m
Coordinate
-0.830, -91.170
Ultima eruzione
2018
Contesto tettonico
Rift zone / Oceanic crust (< 15 km)
Forma vulcanica
Shield
Roccia principale
Basalt / Picro-Basalt
Sintesi geologica

The broad shield volcano of Sierra Negra at the southern end of Isabela Island contains a shallow 7 x 10.5 km caldera that is the largest in the Galápagos Islands. Flank vents abound, including cinder cones and spatter cones concentrated along an ENE-trending rift system and tuff cones along the coast and forming offshore islands. Although it is the largest of the five major Isabela volcanoes, it has the flattest slopes, averaging less than 5° and diminishing to 2° near the coast. A sinuous 14-km-long, N-S-trending ridge occupies the west part of the caldera floor, which lies only about 100 m below its rim. The Volcán de Azufre fumarolic area lies within a graben between this ridge and the west caldera wall. Lava flows from a major eruption in 1979 extend all the way to the north coast from circumferential fissure vents on the upper northern flank.

Sintesi da Wikipedia

Riassunto in inglese

Sierra Negra is a large shield volcano at the southeastern end of Isabela Island in the Galapagos that rises to an altitude of 1124m. It coalesces with the volcanoes Cerro Azul to the west and Alcedo to the north. It is one of the most active of the Galapagos volcanoes with the most recent historic eruption beginning in June 2018 and continuing through the summer.

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Storia delle eruzioni

Riepilogo (VEI nel tempo)
Fai clic su una barra per vedere le singole eruzioni
8250 BCE~7908 BCE · 1 eruzioni · VEI max. 01405 BCE~1062 BCE · 1 eruzioni · VEI max. 0307~649 · 1 eruzioni · VEI max. 0991~1333 · 1 eruzioni · VEI max. 01333~1676 · 1 eruzioni · VEI max. 01676~2018 · 13 eruzioni · VEI max. 38250 BCE5854 BCE3116 BCE720 BCE1676

Cronologia dettagliata

  1. 2018VEI 2Osservata
    2018-06-26 – 2018-08-23
    Summit crater and NNW flank, Volcan Chico fissure vent
  2. 2005VEI 3Osservata
    2005-10-22 – 2005-10-30
    North caldera rim
  3. 1979VEI 3Osservata
    1979-11-13 – 1980-01-14
    Upper NW and NE flanks (Volcán Chico)
  4. 1963VEI 2Osservata
    1963-04-13 – 1963-05-16
    Volcán Chico area & NW caldera rim
  5. 1957VEI ?Stima geologica
    1957-07-02 – In corso
    Volcano Uncertain: Isabela Island
  6. 1954VEI 2Stima geologica
    1954-11-09 – In corso
    Volcano Uncertain: originally Alcedo
  7. 1953VEI 3Osservata
    1953-08-27 – 1954-01-16
    Volcán Chico area & NW caldera rim
  8. 1948VEI 2Osservata
    1948-08 – 1949-02
  9. 1911VEI ?Osservata
    1911-12-31 – In corso
  10. 1860VEI 2Stima geologica
    1860 – In corso
    Volcano Uncertain: Isabela Island
  11. 1844VEI 0Stima geologica
    1844 – In corso
    Volcano Uncertain: Isabela Island
  12. 1817VEI ?Stima geologica
    1817 – In corso
    Volcano Uncertain: Isabela Island
  13. 1813VEI 2Stima geologica
    1813-07-13 – In corso
    Volcano Uncertain: South end of Isabela Island
  14. 1350 (±500 anni)VEI 0Stima geologica
    1350 – In corso
  15. 1060 (±500 anni)VEI 0Stima geologica
    1060 – In corso
  16. 370 (±1100 anni)VEI 0Stima geologica
    370 – In corso
  17. 1250 a.C. (±100 anni)VEI 0Stima geologica
    BCE 1250 – In corso
    SE flank
  18. 8250 a.C. (±1600 anni)VEI 0Stima geologica
    BCE 8250 – In corso

Link esterni

⚠ Solo a scopo informativo. Non adatto a situazioni di emergenza.