Mahukona, Hawaii

Mahukona (20.1N, 156.1W)is a submarine volcano on the northwest flank of the Island of Hawaii. A drowned coral reef at about 3,770 feet (-1,150 m) below sea level and a major break in slope at about 4,400 feet (-1,340 m) below sea level represent old shorelines. The summit of the volcano was once 800 feet (250 m) above sea level. It has now subsided 3,600 feet (-1100 m) below sea level. A roughly circular caldera marks the summit of Mahukona. A prominent rift zone extends to the west. A second rift zone probably extended to the east but has been buried by younger volcanoes. The main shield-building stage of volcanism ended about 470,000 years ago. The summit of the volcano subsided below sea level between 435,000 and 365,000 years ago.

Source information: Clague, D.A., and Moore, J.G., 1991, Geology and Petrology of Mahukona Volcano, Hawaii: Bulletin of Volcanology, v. 53, p. 159-172.

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