In a new study published in the journal Geophysical Research Letters, scientists believe they have discovered the reason why Bermuda never sank after its volcanoes deactivated more than 30 million years ago. Typically, when volcanoes die out, the tectonic plate moves away from the deep mantle hotspot, and the crust and volcano, as they cool, slowly sink. However, scientists have discovered an unusual layer of rock beneath the oceanic crust beneath Bermuda, pushing the island, one of the points of origin of the area called the Bermuda Triangle, upward.
- Caves on the moon? New discovery strengthens plans for future human bases beneath the lunar surface
- See also: The footprints show the dinosaur may have walked with a limp while making a rare turn 150 million years ago.
The layer is 20 km thick, a level never before observed anywhere in the world. The team, led by seismologist William Frazer of the Carnegie Science Research Institute and Jeffrey Park of Yale University, analyzed seismic waves from 396 distant earthquakes, all strong enough to send vibrations of their own through the Earth.
Using these waves and the records they left behind, researchers were able to draw a vertical picture of the rocks beneath Bermuda, down to about 31 miles deep. The image revealed a thick layer of rock that was less dense than the rocks surrounding it.
/i.s3.glbimg.com/v1/AUTH_da025474c0c44edd99332dddb09cabe8/internal_photos/bs/2025/C/G/KNfXpySpyCHdEOUfv3ug/map-earthquakes-used-study-b-117388087.webp)
Frazer explained that normally, past the base of the oceanic crust, one would expect to find the Earth’s mantle. “But in Bermuda, there is this other layer which is positioned under the crust, within the tectonic plate on which Bermuda rests,” he explained to the specialist magazine Live Science.
- Lunar calendar: see the moon phases predicted for December 2025
Bermuda is located on an ocean hill, where the oceanic crust is higher than its surroundings, rising about 500 meters (1,640 ft) above the seafloor. This discovery suggests that the last volcanic eruption could have inserted the mantle rock into the crust, where it would have frozen in place and created a raft-like structure above the ocean floor.
The origin of this layer is not immediately clear, but Park told Brighter Side of News that “some of the magma could have been trapped beneath the surface rather than erupting, forming a mafic pluton over time.”
“We found that volatile-rich melts rising beneath Bermuda could also have effectively depleted and modified the upper mantle, leaving behind a lighter residue,” he added. “Another possibility is metasomatic underplating, in which rising hot material fractures the crust, allows seawater to enter, and partially serpentines the mantle.”
Despite 31 million years of volcanic inactivity at the site, the ocean rise has yet to subside, and although there is debate about what might be happening below the surface, there have been no volcanic eruptions on the surface.
“There is still this material from the time of active volcanism under Bermuda that potentially helps maintain this high relief area in the Atlantic Ocean,” Sarah Mazza, a geologist at Smith College in Massachusetts who was not involved in the study, told Live Science. “The fact that we are in an area that was previously the heart of the last supercontinent explains, I believe, part of why this is unique,” he added.
Today, Frazer is studying other islands around the world to see if there are layers similar to those discovered beneath Bermuda or if they are truly unique.
“Understanding a place like Bermuda, which is an extreme place, is important for understanding less extreme places and gives us an idea of the more normal processes that occur on Earth and the more extreme processes that occur,” Frazer said.
About The Author
