Honolulu:  Scientists in Hawaii say that they have discovered an ancient underwater volcano, now dormant, that once extended 3,000 feet above sea level and is believed to have helped form the island of Oahu. The newly documented volcano, named Kaena, began erupting some 5 million years ago in the channel between what is now Oahu and its neighbour island Kauai, according to a study published this month in the Geological Society […]