‘Enormous’ mountain on Pacific seafloor rivals Rocky Mountain peaks, NOAA says

An “enormous” submerged mountain that rivals peaks in the Rockies has been mapped for the first time in a previously unexplored area of the western Pacific, according to NOAA Ocean Exploration.

The seamount is 250 miles north of Palau — an island country east of the Philippines — and multibeam sonar revealed its peak is hidden about 800 feet below the surface.

“This seamount stretches from the abyssal plain at roughly 4,400 meters (2.7 miles) depth to its peak — meaning it is about 4,200 meters (2.6 miles) tall,” NOAA marine policy fellow Garret O’Donnell wrote in a field report posted Sept. 2.

“By comparison, Pikes Peak, one of Colorado’s fabled ‘14’ers’ — that is, mountains that reach over 14,000 feet in elevation — stands at 14,110 feet (4,302 meters) tall. This unnamed undersea mountain would look right at home among the American Rockies instead of submerged beneath the choppy waters of the western Pacific Ocean.”

Evidence of a peak below the surface appeared in nautical charts in 2023, but the scientists were taken off guard by “the sheer scale of what’s beneath,” Garrett wrote.

“It’s funny to me that were we not actively mapping these features, we would have no idea that a mountain half the height of Mount Everest lies directly beneath us,” he said.

“I can’t help but think about the variety of organisms and geologic features that sit below us, undisturbed and undiscovered. Maybe one day the map we made of this behemoth will be used to navigate the feature with a remotely operated vehicle to get a closer look.”

NOAA Ocean Exploration visited the site as part of the Beyond the Blue expedition, which is exploring mysterious deep water regions of the Palau National Marine Sanctuary.

Seamounts are typically extinct volcanoes that either didn’t reach the surface or were submerged over the centuries, experts say.

It’s suspected there may be 100,000 seamounts hidden in the world’s oceans, “however, less than one-tenth of a percent of the seamounts in the world have been explored,” NOAA says.

This story was originally published September 11, 2025 at 11:26 AM with the headline "‘Enormous’ mountain on Pacific seafloor rivals Rocky Mountain peaks, NOAA says."