The Surtsey eruption is among the longest eruptions to have occurred in Iceland in historical times. The first sign of an eruption came early in the morning of November 14, 1963, at a site approximately 18 km southwest of Heimaey, the largest of the Vestmannaeyjar (Westman Islands). The eruption is believed to have commenced a few days earlier on the sea floor, at a depth of 130 m. Explosive phases characterized the Surtsey eruption in the beginning, and due to the rapid cooling effects of the sea, the hot magma transformed into tephra (volcanic ash). The tephra production was tremendous, and an island had already been formed the day after – on November 15. By the end of January 1964, the new island’s elevation was 174 m, or over 300 m above the sea floor where it had all begun. The eruption activity moved to the northwest on February 1, 1964,...
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