An ancient underwater volcano has just been discovered in Hawaii. It was previously believed that the Island of Oahu had been created by two volcanoes, Wai'anae and Ko'olau, but this discovery reveals that there were actually three active volcanoes.

"I think we may very well have had three active volcanoes in the Oahu region," said lead study author John Sinton, a geologist at the University of Hawaii at Manoa as noted by Fox News.

The Geological Society of America Bulletin writes that the volcano is dubbed as Ka'ena. The now dormant volcano was born in the channel south of Kauai and began to erupt about 5 million years ago, making it the oldest of the three. Researchers then estimate that Wai'anae rose on Ka'ena's flanks 3.9 million years ago and Ko'olau, the latest to surface came up about 3 million years ago.

At about 2.5 miles high, Ka'ena reached about 3,000 feet above sea level and was the shortest of the three peaks, according to LiveScience. Ka'ena used to be above sea level but only briefly and is now completely submerged underwater because evidence found shows it's capped with lavas with textures attributed to interaction with open air.

"The first ones, because they form in deep water, they kind of escape notice," Sinton continues. "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."

Earlier, prior to Ka'ena's discovery, it was assumed that Wai'anae was very large and was formed unusually far from Kaua'i.

Professor Sinton explained, "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."

For more information and to read the University's article/ press release on the discovery of the precursor volcano, you may refer to the institution's site.