Plate Nº 18 · recorded November 13, 2026
Earth & ClimateReported finding
Two Hot Zones Near Earth's Core May Fuel Undersea Volcanoes
Two hot zones near the Earth's core may drive most volcanic activity within oceanic plates, building seamounts up to 4,000 meters tall, a Nature Geoscience study finds.
By Elena Vasquez4 min read730 words
In brief
- The study was published in Nature Geoscience in 2026 by Clint Conrad and Mathew Domeier of the University of Oslo.
- Seamounts can rise as much as 4,000 meters (13,100 feet) above the seafloor.
- Two LLSVPs — one under Africa, one under the Pacific — may have existed for billions of years.
- The Hawaiian–Emperor chain contains more than 80 identified submarine volcanoes.
- The ocean covers about 70% of Earth's surface, yet much of its floor remains unexplored.
Two giant hot zones sitting near the boundary between Earth's mantle and its core may drive much of the volcanic activity that builds mountains on the ocean floor. That's the central finding of a new study published in Nature Geoscience by Clint Conrad and Mathew Domeier, two geoscientists at the University of Oslo.
The structures in question are called LLSVPs — short for large low seismic velocity provinces. There are two of them: one beneath Africa, one beneath the Pacific. "They are like two 'island-like' hot zones near Earth's core—enigmatic but important structures that may have existed for billions of years," Conrad said.
What did the researchers actually find?
Conrad and Domeier traced a connection between these deep structures and seamounts — mountains on the seafloor, often ancient extinct volcanoes, that can rise as much as 4,000 meters (13,100 feet) above the ocean floor. Many never break the surface at all.
"Seamounts are mountains beneath the sea. They come in all sizes, and many are completely invisible from the surface. Researchers can locate them by using satellites to detect small variations in gravity," Domeier explained.
The study's key result: volcanic activity on seamounts is more extensive on seafloor that has previously passed over an LLSVP. "We see that volcanic activity on seamounts is more extensive on seafloor that has previously passed over such LLSVPs—large regions where seismic S-waves travel more slowly," Domeier said.
S-waves, in plain terms, are seismic vibrations from earthquakes that travel through the planet. They slow down inside these provinces because the rock there is hotter and softer than its surroundings.
The takeaway: where the ocean floor once drifted over one of these deep hot zones, it grew more volcanoes.
How do deep structures build mountains on the seafloor?
The mechanism, as the researchers propose it, works in steps:
- The two LLSVPs are hotter and less rigid than the surrounding mantle.
- Weak plumes of hot rock rise from them toward the surface.
- Those plumes interact with the drifting seafloor and promote volcanic activity on seamounts.
- The process may be especially strong in the Pacific, where mantle rocks can be hotter and wetter — and therefore more dynamic.
The study suggests plumes carrying heat from the LLSVPs are likely responsible for most volcanic activity within oceanic plates, including scattered seamounts. This remains a proposed mechanism, not a directly observed one — nobody can watch rock rising through 2,900 kilometers of mantle.
One example stands out. The Hawaiian–Emperor seamount chain, an undersea mountain range in the Pacific containing more than 80 identified submarine volcanoes, has drifted over one of the LLSVPs. That long passage, the researchers argue, produced sustained volcanic activity and built the chain of mountains, with the Hawaiian ridge eventually rising above sea level to form the Hawaiian Islands.
"The Hawaiian–Emperor seamount chain is a good example of how the deep mantle can control where and when seamounts form. In our study, we show that similar processes may have been important in many places on the seafloor," Domeier said.
Why do seamounts matter?
The ocean covers roughly 70% of Earth's surface, yet large parts of the seafloor remain barely explored. "The deep oceans and the life they host are still something we know surprisingly little about," Conrad noted.
Seamounts matter for several practical reasons:
- Hazard. Submarines have crashed into uncharted seamounts.
- Habitat. They provide hard substrate, shelter, favorable currents and rich nutrients, and can serve as stopovers for migratory species.
- Ocean circulation. Water forced up and around seamounts carries nutrients toward the surface, creating rich feeding grounds for fish, marine mammals and seabirds.
- Planetary history. Because seamount volcanism is sensitive to the deep mantle, it offers a record of how Earth's interior has changed over geological time.
Norwegian waters hold their own examples. Conrad points to seamounts near Svalbard and in areas around Jan Mayen and Bouvet Island. These structures are drawing attention from Norwegian Arctic efforts, including the GoNorth expedition and the government's Arctic Ocean 2050 initiative.
The study, "Seamount volcanism associated with Earth's basal mantle structures," appears in Nature Geoscience (2026), DOI: 10.1038/s41561-026-02007-z.
In short: two ancient hot zones at the bottom of the mantle may have shaped volcanoes across much of the ocean floor — and the mountains they built are still shaping ocean life today.
via phys.org/rss-feed/ (Source)
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Correspondent covering money, funding and market shifts around general science news at SciBeat.
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