[Rockhounds] World’s biggest volcano is barely visible

[Kreigh Tomaszewski]

Two small, guano-covered islands that peek above the waves in the central
North Pacific Ocean are merely the tips of our planet’s largest single
volcano, new research reveals.

Pūhāhonu—Hawaiian for “turtle surfacing for air”—lies about 1100 kilometers
northwest of Honolulu. It is a shield volcano—a broad dome that rises about
4500 meters from the sea floor from a single source of molten rock. In an
analysis reported this month in Earth and Planetary Science Letters,
researchers
estimate that Pūhāhonu contains approximately 150,000 cubic kilometers
<https://www.sciencedirect.com/science/article/pii/S0012821X20302399> of
rock, based on a 2014 sonar survey.

But only one-third of that volume is exposed above the sea floor; the rest
is buried beneath a ring of debris, broken coral, and other material that
has eroded from the peak. Pūhāhonu is so heavy, researchers note, that it
has caused Earth’s crust nearby—and thus the volcano itself—to sink
hundreds of meters over millions of years.

https://www.sciencemag.org/news/2020/05/world-s-biggest-volcano-barely-visible