Māhukona is a submerged
shield volcano
A shield volcano is a type of volcano named for its low profile, resembling a warrior's 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 v ...
on the northwestern flank of the
Island of Hawaii
Hawaii ( ; haw, Hawaii ) is the largest island in the United States, located in the state of Hawaii. It is the southeasternmost of the Hawaiian Islands, a chain of volcanic islands in the North Pacific Ocean. With an area of , it has 63% of th ...
. 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 volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...
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 t ...
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 ( or ; ; abbreviation for ''Mauna a Wākea''); is a dormant volcano on the island of Hawaii. Its peak is above sea level, making it the highest point in the state of Hawaii and second-highest peak of an island on Earth. The peak is ...
.
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 Foundation ...
investigated the area with a remotely controlled submarine in 2001.
It was named for the area known as
Māhukona
Māhukona is a submerged shield volcano on the northwestern 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 ol ...
, on the shore to the northeast.
References
Further reading
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External links
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Volcanoes of Hawaii
Hawaiian–Emperor seamount chain
Shield volcanoes of the United States
Hotspot volcanoes
Extinct volcanoes
Polygenetic shield volcanoes
Pleistocene shield volcanoes
Pleistocene Oceania
Cenozoic Hawaii
Calderas of Hawaii
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