A rocky resting place

(Image credit: University of Hawaii at Manoa)A newly-discovered volcano, named Ka'ena, erupted 5 million years ago in the deep waters south of Kauai. It was the first of three volcanoes that would form the island of Oahu. Researchers recently showed that Ka'ena was a separate volcano, distinct from its neighbor, Wai'anae volcano.

Former island

(Image credit: University of Hawaii at Manoa)The blocky texture of these a'a lavas only forms in air, a clue that Ka'ena volcano once poked above the ocean surface 3 million years ago.

Friendly visitor

(Image credit: University of Hawaii at Manoa)Researchers snapped images of local marine life while searching for signs of past eruptions.

Sampling rocks

(Image credit: University of Hawaii at Manoa)Rock samples collected with a remotely operated vehicle helped prove Ka'ena volcano is older and chemical distinct from its neighbors.

Where fire meets the sea

(Image credit: University of Hawaii at Manoa)Sheets of hyaloclastite, a glassy lava that forms where molten rock meets the sea.