Scientists have discovered the Earth’s largest volcano using bathymetric and gravity mapping. After running calculations and petrologic analyses, researchers have determined that the Hawaiian volcano Pūhāhonu is the largest and hottest shield volcano in the world. Also known as Garner Pinnacles, Pūhāhonu means ‘turtle rising for breath’ in Hawaiian. With a calculated size of 150,000 cubic kilometers of rock (∼12.5-14.1 Ma), Pūhāhonu is roughly twice the volume of Mauna Loa volcano, the world’s tallest shield volcano. Located in the northwest Hawaiian Ridge (NWHR), only about 30% of that volume is located above the sea floor.
In 2014, sonar surveys of the volcano were collected. This data was combined with existing bathymetric synthesis for the NWHR and a lower resolution SRTM15+V2 global bathymetry and topography data set. The results from analyzing the combined datasets showed that the subaerial twin Gardner Pinnacles visible above sea level are just a tiny portion of the massive morphology of Pūhāhonu. These two small and barren peaks rise only 170 feet above sea level. Much of the mass of Pūhāhonu lies obscured beneath the seafloor after 14 millions of years of lava output created a mass heavy enough to bend the ocean crust.
Garcia, M. O., Tree, J. P., Wessel, P., & Smith, J. R. (2020). Pūhāhonu: Earth’s biggest and hottest shield volcano. Earth and Planetary Science Letters, 542, 116296. https://doi.org/10.1016/j.epsl.2020.116296
Grabowski, M. (2020, May 13). SOEST researchers reveal largest and hottest shield volcano on earth. https://www.soest.hawaii.edu/soestwp/announce/news/uh-researchers-reveal-largest-and-hottest-shield-volcano-on-earth/