lundi, juin 04, 2012
Fayal volcanThe island of Fayal, also spelled Faial, is the nearest of the central Azorean islands to the Mid-Atlantic Ridge.
Introduction:The island is composed of a complex large andesitic-to-trachytic stratovolcano that contains a 2-km-wide summit caldera. Thick deposits of trachytic airfall pumice, pyroclastic flows, and lahars related to formation of the caldera blanket the island. Formation of the steep-walled 500-m-deep caldera was followed by construction of fissure-fed basaltic lava fields and small volcanoes that form a peninsula extending to the west. This area is covered by the youngest volcanic products on the island and has been the source of all historical eruptions. A dramatic submarine eruption at Capelinhos during 1957-58, the best-studied of historical eruptions in the Azores, created a new island that soon merged with the western peninsula.
Source: Smithsonian GVP
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