Māhukona is a submerged

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava ...

on the northwestern flank of the

Island of Hawaii Hawaii is the List of islands of the United States by area, largest island in the United States, located in the Hawaii, state of Hawaii, the southernmost state in the union. It is the southeasternmost of the Hawaiian Islands, a chain of volcani ...

. 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. A roughly circular

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

marks its summit. A prominent

rift zone A rift zone is a feature of some volcanoes, especially shield volcanoes, in which a set of linear cracks (or rifts) develops in a volcanic edifice, typically forming into two or three well-defined regions along the flanks of the vent. Believed ...

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 shield volcano was once 800 feet (250 m) above sea level, but subsided below sea level between 435,000 and 365,000 years ago. Māhukona is the oldest volcano to build Hawaii island, older than Kohala and

Mauna Kea Mauna Kea (, ; abbreviation for ''Mauna a Wākea''); is a dormant Shield volcano, shield volcano on the Hawaii (island), island of Hawaii. Its peak is above sea level, making it the List of U.S. states by elevation, highest point in Hawaii a ...

. The

Monterey Bay Aquarium Research Institute The Monterey Bay Aquarium Research Institute (MBARI) is a private, non-profit oceanographic research center in Moss Landing, California. MBARI was founded in 1987 by David Packard, and is primarily funded by the David and Lucile Packard Foun ...

investigated the area with a remotely controlled submarine in 2001. It was named for the area known as Māhukona, on the shore to the northeast.

References

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* Volcanoes of Hawaii Hawaiian–Emperor seamount chain Shield volcanoes of the United States Hotspot volcanoes Extinct volcanoes of the United States Polygenetic shield volcanoes Pleistocene shield volcanoes Pleistocene Oceania Cenozoic Hawaii Calderas of Hawaii {{Hawaii-geo-stub

References

Further reading

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