Researchers recently discovered that O'ahu, Hawai'i actually consists of three major Hawaiian shield volcanoes, not two, as previously thought. Extending almost 100 km WNW from the western tip of the island of O'ahu is the submarine Ka'ena Ridge, a region that has now been recognized to represent a precursor volcano to the island of O'ahu, and on whose flanks the Wai'anae and Ko'olau Volcanoes later formed....