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A Report by Andrew Collins
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ATLANTIS & the Atlantic Ocean

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Author Topic: ATLANTIS & the Atlantic Ocean  (Read 22110 times)
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« Reply #345 on: March 30, 2009, 12:04:47 am »

   Don Joao de Castro Bank

Two unusual-looking flank craters are visible in this side-viewing sonar perspective of the NW flank of Don Joao de Castro Bank in the Azores taken by U.S. Navy submarine NR-1. The two craters are 90 x 45 m wide. The left-hand and younger crater displays a floor consisting of a chilled lava lake with polygonal surface fractures. The right-hand crater is much less distinct because its surface is obscured by tephra deposits. The line at the right is the center track line of the sonar image.

U. S. Navy image courtesy of Rick Wunderman, 2003 (Smithsonian Institution).

Country: Portugal
Subregion Name: Azores and Madeira
Volcano Number: 1802-07=
Volcano Type: Submarine volcano
Volcano Status: Historical
Last Known Eruption: 1720   
Summit Elevation: -14 m - 46 feet
Latitude: 38.23°N  38°14'0"N
Longitude: 26.63°W 26°38'0"W
Don Joao de Castro Bank is a large submarine volcano that rises to within 14 m of the sea surface roughly halfway between Terceira and San Miguel Islands. A submarine eruption during December 1720 produced an ephemeral island that attained a length of 1.5 km and an altitude of about 250 m before it was eroded beneath the sea surface two years later. The volcano (also spelled Dom Joao de Castro) was named after the Portuguese hydrographic survey vessel that surveyed the bank in 1941. Two youthful parasitic craters, one tephra covered and the other sediment free, are located on the NW flank. The submarine volcano has an impressive fumarole field and remains seismically active. 
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