World’s Largest Shield Volcano Pūhāhonu (AKA Gardner Pinnacles) Found in Hawaii
So apparently weve been wrong about the worlds largest volcano this whole time. Like completely wrong. Everyone and their grandmother thought it was Mauna Loa – that massive beast on the Big Island that dominates every geology textbook ever written, the one tourists gawk at, the one that makes Hawaiian postcards look dramatic. But nope. Turns out theres something even bigger lurking beneath the waves about 1,000 kilometers northwest of Honolulu, and its called Pūhāhonu. And nobody really knew until now.
The name means “turtle rising for breath” in Hawaiian which honestly is such a beautiful image when you think about it. Picture this massive ancient volcano barely poking above the ocean surface like a sea turtle coming up for air. Thats what Hawaiian navigators saw centuries ago and thats the name that stuck with them. These researchers at the University of Hawaii at Mānoa have been surveying the ocean floor and crunching numbers for years, and what they found is kind of mind-blowing. This thing is nearly TWICE the size of Mauna Loa. Like… twice. Not 10% bigger, not 50% bigger – literally double. We actually covered the initial discovery here but the full scope of what theyre dealing with keeps getting more impressive the more they study it.
The Numbers Are Absolutely Bonkers
According to the university research team, Pūhāhonu contains roughly 150,000 cubic kilometers of rock. Thats 36,000 cubic miles for the Americans in the room who refuse to learn metric. Im not even sure how to visualize that amount of material honestly. The thing is so massive that its literally causing the Earths crust to sink underneath it. Like imagine something so heavy it actually deforms the planet itself. The hot mantle underneath just flows away because theres this incomprehensible weight pressing down. Thats what were dealing with here and I genuinely cant wrap my head around it.
And heres the kicker that really got me – its also the HOTTEST shield volcano ever recorded on Earth. The magma temperatures hit around 1,700 degrees Celsius which is just… I dont even know how to process that information. Thats hot enough to melt basically anything. Lead researcher Michael Garcia told CNN that finding this in the 21st century was surprising quote “but then we know more about the surface of Mars than what is below the ocean on Earth.” Which honestly makes me feel some type of way about our priorities as a species but thats a rant for another day I suppose.
Why Didnt We Know Sooner Though
The thing is, Pūhāhonu barely sticks above sea level. Were talking about two little rocky peaks that rise maybe 170 feet above the water – thats like a 17-story building, which sounds big until you realize the vast majority of this volcano is hidden underwater and underground. Sailors called them Gardner Pinnacles after some 19th century discovery, and for over a hundred years nobody really thought much about what might be underneath. Just some rocks in the ocean right? Wrong apparently.
It wasnt until researchers got proper sonar surveys done in 2014 and started modeling the ocean floor that the true scale became apparent. They used gravity measurements and chemical analysis of rock samples to figure out how much material was actually there. The science is pretty fascinating if youre into that sort of thing – basically they can tell how hot the original magma was by looking at certain minerals in the rocks. The hotter the source, the different the mineral composition. And Pūhāhonu’s rocks showed signs of absolutely scorching temperatures.
Garcia and his team are pushing for everyone to use the Hawaiian name instead of the Western one. “We are sharing with the science community and the public that we should be calling this volcano by the name the Hawaiians have given to it,” he said. Fair point honestly. The Hawaiians knew about this place for centuries before any European sailor showed up. Seems right to use their name.
The volcano is now part of the Papahānaumokuākea Marine National Monument and hasnt erupted in about 12-14 million years so nobody needs to panic about it going off anytime soon. Its completely extinct at this point, just sitting there being enormous. But still. The largest volcano on Earth was just chilling there this whole time and we had no idea. Makes you wonder what else were missing in our own backyard while we send robots to Mars.
