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Furnas

Stratovolcano · Portugal · 805m

Furnas volcano, at the eastern end of Sao Miguel Island, contains two nested calderas. The southern rim of the younger 6-km-wide caldera is seen here from the north, with Furnas Lake on the right foreground. At least 10 trachytic pumice layers, all erupted during the past 5,000 years, post-date the caldera. The dome with the semi-circle of trees in the center behind the lake is the site of the most recent eruption at Furnas, a sub-Plinian eruption in 1630 CE.
Furnas volcano, at the eastern end of Sao Miguel Island, contains two nested calderas. The southern rim of the younger 6-km-wide caldera is seen here from the north, with Furnas Lake on the right foreground. At least 10 trachytic pumice layers, all erupted during the past 5,000 years, post-date the caldera. The dome with the semi-circle of trees in the center behind the lake is the site of the most recent eruption at Furnas, a sub-Plinian eruption in 1630 CE. · Photo: Photo by Rick Wunderman, 1997 (Smithsonian Institution). · Wikimedia Commons
Type
Stratovolcano
Country
Portugal
Region
Atlantic Ocean Volcanic Regions / Azores-Terceira Rift Volcanic Province
Elevation
805m
Coordinates
37.770, -25.320
Last eruption
1630
Tectonic setting
Rift zone / Oceanic crust (< 15 km)
Landform
Composite
Major rock type
Trachyte / Trachydacite
Geological summary

Furnas volcano lies at the eastern end of Sao Miguel Island, immediately west of the older Nordeste shield volcano and its Povoaçao caldera. There are 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 Furnas caldera overlaps the western wall of the Nordeste Povoaçao caldera. Volcanic activity 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, 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.

From Wikipedia

Furnas is a civil parish in the municipality of Povoação on the island of São Miguel in the Portuguese Azores. The population in 2011 was 1,439, in an area of 34.43 km2. The parish is one of the largest in the island and in the Azores. It is located east of Lagoa and Ponta Delgada, west of Povoação and southeast of Ribeira Grande.

Wikipedia · CC BY-SA · Read full article →

Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
4570 BCE~4363 BCE · 1 eruptions · max VEI ?1677 BCE~1470 BCE · 1 eruptions · max VEI ?437 BCE~230 BCE · 1 eruptions · max VEI ?23 BCE~183 · 1 eruptions · max VEI 5803~1010 · 1 eruptions · max VEI 41010~1217 · 1 eruptions · max VEI 41423~1630 · 3 eruptions · max VEI 54570 BCE3123 BCE1470 BCE23 BCE1423

Detailed timeline

  1. 1630VEI 5Observed
    1630-09-03 – 1630-11-02
    South end of caldera (Pico da Areia)
  2. 1441 (±2 yrs)VEI 4Observed
    1441 – Ongoing
    Center of caldera (Gaspar)
  3. 1430 (±100 yrs)VEI 3Geological estimate
    1430 – Ongoing
    East caldera floor
  4. 1170 (±100 yrs)VEI 4Geological estimate
    1170 – Ongoing
    E caldera floor (Lake crater)
  5. 840 (±100 yrs)VEI 4Geological estimate
    840 – Ongoing
    Center of caldera (Gaspar)
  6. 80 (±100 yrs)VEI 5Geological estimate
    80 – Ongoing
    N floor of younger caldera
  7. 360 BCE (±150 yrs)VEI ?Geological estimate
    BCE 360 – Ongoing
  8. 1670 BCE (±1460 yrs)VEI ?Geological estimate
    BCE 1670 – Ongoing
  9. 4570 BCEVEI ?Geological estimate
    BCE 4570 – Ongoing
    East rim of caldera (Pico do Canário)

External links

⚠ For reference only. Not for emergency response.