Scientists have discovered a third volcano under the Hawaiian island of Oahu that now accompanies Wai'anae to the west and Ko'olau to the east.
According to LiveScience.com, the discovery challenges what scientist previously knew about the island - that it was built on two volcanoes. Authors of the study, published in the Geological Society of America Bulletin, said Oahu would have towered over the ocean with three volcanic peaks instead of two.
The researchers said the third volcano, named Ka'ena, emerged from the sea five million years ago, predating the other two. They said Wai'anae originated 3.9 million years ago and Ko'olau did so three million years ago.
"I think we may very well have had three active volcanoes in the Oahu region," study lead study author John Sinton, a geologist at the University of Hawaii at Manoa, told LiveScience.com.
The researchers said Ka'ena is 2.5 miles high, but only stood 3,000 above sea level because it was the first to emerge from the sea and had to grow farthest from the floor.
"The first ones, because they form in deep water, they kind of escapenotice," Sinton said. "We like to think we know how many Hawaiian volcanoes there are, but what we know about what's underwater is a huge area of ignorance."
They determined Ka'ena was once an island peak because they found lava textures on its cap that could only have been formed with air, thanks to a remote controlled vehicle.
"Both of these assumptions can now be revised: Wai'anae is not as large as previously thought and Ka'ena Volcano formed in the region between Kauai and Wai'anae," Sinton said in a press release. "What is particularly interesting is that Ka'ena appears to have had an unusually prolonged history as a submarine volcano, only breaching the ocean surface very late in its history."
