If you guessed Hawaii, you’re right. Researchers University of Hawai’i at Mānoa The School of Ocean and Earth Sciences and Technologies reveals that the Pūhāhonu volcano now holds the distinction of the largest and hottest shield volcano on Earth.
Ocean explorers and volcanologists have used several pieces of evidence to point out that the volcano inside the Papahānaumokuākea National Marine Monument now beats Mauna Loa.
After a careful study of the ocean floor along the calm Hawaiian volcanic chain and an analysis of the rocks in the UH Mānoa rock collection, the researchers set up a model of the results they collected, leading them to this new conclusion.
They determined that the Pūhāhonu volcano, which meant “turtle rising to breathe”, was almost twice the size of Mauna Loa. 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 former Earth Sciences professor at SOEST, it has been suggested that the hot spots that make up volcanic chains like those in Hawaii be subjected to continuous cooling over one to two million years, after which they die .
However, he adds that they have learned that hot spots can go through pulses of melt production through their study. Garcia said that a small impulse led to the creation of the Midway cluster of currently extinct volcanoes, and that other larger ones were responsible for the creation of Pūhāhonu. He says it will change textbooks around the world on how the mantle plumes work.
Previous studies of 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 taken into account in the 1974 study. Now a large survey and modeling using approaches similar to those used for Mauna Loa now indicate that Pūhāhonu is the most important.
According to the volcanologists, the study presents 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 also share with everyone that volcanoes should be called the Hawaiian names they originally owned, rather than converting them to western names. Their work was funded by the University of Hawaii, the National Science Foundation and the Schmidt Ocean Institute.
Shield volcanoes are considered the largest volcanoes on Earth. A well-known example is the volcanoes of the Hawaiian shield. The volcanoes of the Shield are almost entirely made from basalt, a type of lava that is very fluid when it erupts.
For this reason, the shield volcanoes are not stiff. Eruptions on shield volcanoes are only explosive if water escapes through the vent. Usually, they are characterized by a weak push of “fountain” which forms cones of ash and stops the cones at the vent. Nevertheless, about 90% of the volcano is lava rather than pyroclastic substances.
Shield volcanoes are the product of high magma supply rates. This happens when the lava is hot and has undergone 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 on their own.
Examples of shield volcanoes are Kilauea, Mauna Loa, Erta Ale, Fernandina, Karthala, Masaya, Tolbachik, and of course, Pūhāhonu.