Thousands of years ago when volcanoes were still active in Oahu, Koko Crater’s lava flowed into this area of the ocean. The molten lava tubes that occurred thousands of years ago formed the natural occurrence we now kn0w as Halona Blowhole. The lava tubes extend into the ocean which are narrow at the top and, when the surf is favorable, this blowhole can shoot sea spray up to thirty feet high in the air. The geyser is most active when the tide is high and the winds are strong. On a calm and clear day, the island of Moloka’i can also be observed in the distance.