If you guessed Hawaii, then you're right. Researchers from the University of Hawai'i at Mānoa School of Ocean and Earth Science and Technology reveal that the Pūhāhonu volcano now holds the distinction as Earth's most extensive and hottest shield volcano.
Ocean explorers and volcanologists used several pieces of evidence to point out that the volcano located within the Papahānaumokuākea Marine National Monument now beats Mauna Loa.
After careful survey of the ocean floor along the calm Hawaiian volcano chain and rock analysis in the UH Mānoa rock collection, researchers have put up a model of the results they gathered, leading them to this new conclusion.
They determined that the Pūhāhonu volcano, which meant 'turtle rising for breath', was almost two times bigger than the Mauna Loa. Back in 1974, it was already suspected to be the largest Hawaiian volcano, but due to limited survey data, it was concluded that Mauna Loa was the most massive volcano instead.
According to Michael Garcia, the lead author of the study and a previous professor of Earth Sciences at SOEST, it was suggested that hotspots that make up the volcanic chains like the ones in Hawaii are subjected to continuous cooling over one to two million years, after which, they die.
However, he adds that they have learned that hotspots can go through pulses of melt production from their study. Garcia said that a small pulse led to the creation of the Midway cluster of presently extinct volcanoes, and other far larger ones were responsible for creating Pūhāhonu. He says that this will change textbooks all around the world about how mantle plumes work.
Previous studies concerning the Hawaiian Islands have concluded Mauna Loa as the largest, but this was due to the inclusion of the base of the volcano below sea level. This was not considered in the study of 1974. Now, broad surveying and modeling using approaches similar to those used for Mauna Loa now point to Pūhāhonu being the largest.
According to volcanologists, the study features Hawaiian volcanoes and draws attention to an unpopular part of the state of Hawai'i containing symbolic cultural, historical, and ecological significance.
Garcia explains that they are also sharing to everyone that the volcanoes should be called the Hawaiian names they initially possess, rather than converting them to Western names. Their work was funded by the University of Hawai'i, National Science Foundation, and Schmidt Ocean Institute.
What are Shield Volcanoes?
Shield volcanoes are considered the biggest volcanoes on Earth. A well-known example is the Hawaiian shield volcanoes. Shield volcanoes are almost entirely made from basalt, a type of lava that is very fluid when erupted.
Due to this, shield volcanoes are not steep. Eruptions at shield volcanoes are only explosive if water escapes into the vent. Usually, they are characterized by a low 'fountain' spurt that forms cinder cones and douses cones at the vent. Nonetheless, about 90% of the volcano is lava rather than pyroclastic substances.
Shield volcanoes are the product of high magma supply rates. This occurs when the lava is hot and underwent minimal transformation since the time it was created. Shield volcanoes are the frequent product of hotspot volcanism, but they can also be spotted along volcanic arcs associated with subduction or all by themselves.
Examples of shield volcanoes are Kilauea, Mauna Loa, Erta Ale, Fernandina, Karthala, Masaya, Tolbachik, and of course, the Pūhāhonu.
