All told a dozen previously unknown peaks were discovered beneath the waves—some up to 10,000 feet (3,000 meters) tall, according to the British Antarctic Survey.

The volcanoes were found near the U.K. territories of the South Georgia Islands and South Sandwich Islands.

Read about it here in Nat Geo:  http://news.nationalgeographic.com/news/2011/07/110715-undersea-volcanoes-antarctica-science-tsunamis/?source=email_gg