Dom João de Castro Bank

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Dom João de Castro Bank
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Image wanted BW
height 6.7 m below sea level
location Azores , Atlantic Ocean
Coordinates 38 ° 13 '2 "  N , 26 ° 36' 1"  W Coordinates: 38 ° 13 '2 "  N , 26 ° 36' 1"  W
Dom João de Castro Bank (Azores)
Dom João de Castro Bank
rock Basalt , hyaloclastite
Last eruption 1720
particularities Underwater volcano
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The Dom João de Castro Bank ( Portuguese Banco D. João de Castro ) is an underwater volcano in the Azores , 36  nautical miles (67 km) from Terceira Island and 40 nautical miles (74 km) from São Miguel Island . The volcanic cone rises about 1000 m above the sea floor and has a minimum depth of 6.7 meters. Its oval crater, the bottom of which is up to 50 m below sea level, measures 300 m in north-south direction and 600 m in east-west direction. There are hydrothermal vents at a depth of only 20 m, which reach temperatures of 121 ° C. Gas rises in several places, especially carbon dioxide . It comes from a magma chamber one to five kilometers below the ocean floor. To the southeast of the shallowest part of the bank , a second hydrothermal field was found at a depth of 200 m.

When the volcano erupted in 1720, its ash clouds could be seen as far as São Miguel and Terceira. An island was created with a diameter of 1500 m, but it had disappeared again by 1722. The area around the Dom-João-de-Castro-Bank is seismically active to this day. On June 27, 1997, a severe earthquake with a magnitude of 5.5, which was felt on São Miguel and the islands of the central group of the Azores, had its epicenter here . It was followed by a swarm of around 2,000 individual quakes within a month.

The shoal is named after the 16th century Portuguese navigator João de Castro .

See also

Web links

Individual evidence

  1. ↑ a b c d Sérgio P. Ávila, Frederico Cardigos, Ricardo S. Santos: D. João de Castro Bank, a shallow water hydrothermal-vent in the Azores: checklist of the marine molluscs (PDF; 303 kB). In: Arquipélago. Life and Marine Sciences 21A, 2004, pp. 75-80.
  2. ↑ a b Luis Sobrinho-Gonçalves, Frederico Cardigos: Fish Larvae around a Saemount with Shallow Hydrothermal Vents from the Azores (PDF; 477 kB). In: Thalassas 22, No. 1, 2006, pp. 19-28.
  3. ↑ Sailing Directions (Enroute). West Coast of Europe and Northwest Africa. Pub. 143, National Geospatial-Intelligence Agency, Springfield, Virginia 2017, p. 202: Banco Dom Joao de Castro ( PDF ; 15.9 MB; English).
  4. ^ Dom-João-de-Castro-Bank in the Global Volcanism Program of the Smithsonian Institution (English).