Surprise under a cliff on Hawaii coast

Just rising about 51.8 m above sea level, the Pūhāhonu volcano of the Northwest Hawaiian archipelago does not look great.

Located about 1,000 km northwest of Honolulu, Pūhāhonu volcano means "floating turtle to breathe air" in Hawaiian language. No longer active, two small peaks protruding from the water's surface are also known as Gardner Pinnacles.

Gardner Pinnacles may appear barren, but is home to a number of seabirds. Photo: Lucy Pemoni / AP.

Looking at Pūhāhonu the smaller it is, compared to other volcanoes in the same archipelago like Mauna Kea and Mauna Loa - all at least 3,900 m above sea level.

Scientists from the University of Hawaii at Mānoa have proved that Pūhāhonu's humble appearance is false. A new study published in the journal Earth and Planetary Science Letters points out that Pūhāhonu is the largest shield volcano in the world, surpassing Mauna Loa's height of 4,169 m.

Survey results of the ocean floor and quantitative calculations showed that Pūhāhonu, 275 km long and more than 90 km wide, was twice the size of Mauna Loa.

"Great Pūhāhonu", it wrote, "to the extent that it is possible to submerge the Earth's crust".

Michael Garcia, lead author of the study, said: "The crust construction quickly causes it to sink. When a giant volcano forms, the cover melts, the volcano sinks."

Joseph Allen, captain of the American whale hunter Maru, first discovered Pūhāhonu in 1820, and the crew of a Russian ship were the first to set foot on the mountain in 1828. Pūhāhonu present It is part of the Papahānaumokuākea Maritime National Monument, which was established in 2006. Although home to only one species of succulent marine plants, the island is an ideal habitat for a multitude of fish. coral and insects.

Today visitors to Hawaii can book a tour to explore Gardner Pinnacles, learn about the wildlife world when there are 19 different seabirds nesting on this isolated island, besides the spiders, fish, coral, marine plants ... Photo: Kim Morishige / Papahānaumokuākea Marine National Monument.

A 1974 study considered Pūhāhonu to be the largest volcano in the Hawaii-Emperor submarine chain, based on limited survey data. Subsequent studies have measured both the undersea and protruding from the sea, and concludes that Mauna Loa is the largest volcano. And the latest research updates that conclusion, confirming that the title of the largest shield volcano in the world belongs to Pūhāhonu.

Not only the greatest, Pūhāhonu is also the hottest volcano in the world, these elements are interconnected, according to author Garcia.

"Size and temperature go hand in hand. Larger sizes are usually caused by hot magma. It will erupt more if it's hot," Garcia said.

Analysis of rock samples from Pūhāhonu used to calculate the heat of magma - about 1,700 degrees Celsius. "Finding the largest shield volcano in the world in the 21st century was a surprising discovery, but then Humans understand the Martian surface more than what exists under the Earth's ocean. We are still discovering many unknown things about the planet. There is much more to learn about Earth, "Garcia said.