Latest news with #magma
Yahoo
19 hours ago
- Science
- Yahoo
Scientists discover 'ghost' plume in Earth's mantle that likely rerouted India as it crashed into Eurasia
When you buy through links on our articles, Future and its syndication partners may earn a commission. Scientists have discovered an ancient "ghost" plume lurking beneath Oman. The magma plume is trapped beneath a thick portion of Earth's crust and the upper part of the mantle, the planet's middle layer. As a result, the material can't rise to trigger volcanic activity at the surface. Researchers don't know if the plume ever sparked eruptions, but evidence suggests it shifted the trajectory of the Indian tectonic plate during its collision with Eurasia tens of millions of years ago, according to a new study. The plume sits beneath Oman's Salma Plateau (also spelled Salmah and Selma), which is up to 6,600 feet (2,000 meters) high, said study lead author Simone Pilia, a geophysicist and assistant professor at King Fahd University of Petroleum and Minerals in Saudi Arabia. The plateau likely formed because of the plume, although some scientists link the plateau's formation to the bending of Earth's crust created by the Makran subduction zone off the coasts of Pakistan and Iran, Pilia told Live Science. "A plume is hot material that wants to rise, rise, rise — so it's underneath and it's pushing up, creating topography," Pilia said. "The uplift [at the Salma Plateau] is rather small, but it's still there. It's telling you that the plume is active." Researchers discovered the plume thanks to seismic waves, or sound waves that travel through Earth at different speeds depending on the chemical makeup of the material. Oman has a dense network of stations that record seismic data, which made the research possible, Pilia said. He named the plume "Dani" after his son. Related: Africa is being torn apart by a 'superplume' of hot rock from deep within Earth, study suggests The Dani plume is the first clear example of an amagmatic "ghost" plume — a term the study authors coined to describe mantle plumes that don't trigger volcanic activity. Mantle plumes originate from the core-mantle boundary roughly 1,800 miles (2,900 kilometers) beneath Earth's surface. These plumes typically fuel volcanic eruptions because they undergo a process called decompression melting as they rise through the mantle and crust. Many mantle plumes trigger volcanic eruptions in the middle of oceanic plates, including in Hawaii, Pilia said. But mantle plumes rarely trigger eruptions within continental plates; they can't rise or undergo decompression melting because they continental plates a thicker crust and upper mantle than oceanic plates do. Researchers have generally assumed that the lack of volcanism from mantle plumes in continental plates means that there are no mantle plumes beneath continental plates, Pilia said. But "absence of evidence is not evidence of absence," he said. "If you don't have surface volcanism, it doesn't mean that you don't have a plume." The Dani plume is proof that mantle plumes can exist without volcanic activity. "What we strongly believe is that there are many other ghost plumes that we don't know of," Pilia said. Africa is a good candidate for ghost plumes because it sits above one of Earth's two large low-shear-velocity provinces — continent-size blobs that protrude from the core-mantle boundary and feed plumes. Like Oman, Africa has regions with a very thick crust and upper mantle, so any plumes would be prevented from rising to the surface, Pilia said. "What we strongly believe is that there are many other ghost plumes that we don't know of." The Salma Plateau is around 40 million years old, which means the Dani plume is at least as ancient, according to the study, which was published online June 6 in the journal Earth and Planetary Science Letters. This timing coincides with the collision between the Indian and Eurasian plates — and this got the researchers thinking, Pilia said. The collision happened relatively close to what is now Oman, before the two plates moved northward to their current positions. Pilia and his colleagues reconstructed the trajectory of the Indian plate and found that it changed direction slightly between 40 million and 25 million years ago. RELATED STORIES —Scientists discover 'sunken worlds' hidden deep within Earth's mantle that shouldn't be there —Gargantuan waves in Earth's mantle may make continents rise, new study finds —North America is 'dripping' down into Earth's mantle, scientists discover "We made some other calculations and basically demonstrated that the shear stress produced by the plume was the reason for the change in azimuth [angle] of the Indian plate," Pilia explained. Researchers already knew that plumes can redirect tectonic plates — but until now, without knowledge of the Dani plume, they hadn't tied this shift in trajectory to a specific plume. Tectonic plates move, but plumes tend to stay in place, Pilia said. This means that scientists can sometimes trace the evolution of a plume through evidence left on tectonic plates as they move over the plume. However, in the case of the Dani plume, this evidence has been swallowed and erased by the Makran subduction zone, Pilia said. "That evidence is gone forever."
Daily Mail
16-05-2025
- Science
- Daily Mail
Massive underwater volcano to blow at any moment and release millions of tons of lava
A volcano in the Pacific Northwest is showing signs of re-awakening. The Axial Seamount is a mile-wide underwater volcano that sits 300 miles off the coast of Oregon and more than 4,900 feet below the surface of the Pacific Ocean. Researchers with the National Science Foundation's Ocean Observatories Initiative have been monitoring this inevitable underwater explosion and now say that the volcano is swelling up like a balloon full of lava. According to William Chadwick, a volcanologist and research professor at Oregon State University, the Axial Seamount acts a lot like the volcanoes in Hawaii and is set to spew out over a billion cubic feet of 'very fluid lava' weighing millions of tons at any moment. 'They tend to inflate like a balloon in between eruptions. At Axial, the seafloor is actually rising, and that's a big signal,' Chadwick said. In recent weeks, there has been a massive uptick in the number of earthquakes under the seamount, caused by this magma pushing to the surface. The Axial Seamount last erupted in 2015, triggering roughly 8,000 earthquakes , producing 450-foot-thick lava flows and causing the bottom of the ocean to sink nearly eight feet. William Wilcock, a professor and marine geophysicist at the University of Washington, warned that Axial Seamount could erupt as soon as tomorrow. Situated along the Juan de Fuca Ridge, a chain of undersea volcanoes extending between Oregon and Alaska, Axial Seamount is a young shield volcano - a broader volcano with a low profile. Based on the 2015 eruption, Chadwick added that this year's magma explosion could produce a lava flow that's nearly as tall as Seattle's Space Needle. However, if Axial Seamount does blow within the next few days, experts say it won't pose any threat to communities along the West Coast. It's too deep and far from shore for people to even notice when it erupts, and it has no impact on seismic activity on land. Although few people have felt the tremors, the region has seen a sharp rise in the number of earthquakes in just the last month, with a major spike in activity recorded on April 13. Since May 6, the number of daily earthquakes under the seamount has been steadily rising. The number of underwater quakes is expected to skyrocket during this event, rising from several hundred per day right now to 10,000 earthquakes within a 24-hour period as magma flows out of the seafloor volcano, according to Interesting Engineering. Mike Poland, a scientist at the Yellowstone Volcano Observatory, expressed excitement about the eruption, highlighting Axial Seamount as one of the world's best-monitored submarine volcanoes. 'This particular volcano is probably the best-monitored submarine volcano in the world,' he told Cowboy State Daily. 'It's fascinating and doesn't really pose a hazard.' Despite the growing anticipation among scientists, Axial Seamount's next eruption will likely come as a surprise to everyone tracking it. Wilcock's best guess is that the swelling lava finally erupts later in 2025 or even early 2026, but there's still chance it happens much sooner. Scott Nooner, a professor of geophysics at the University of North Carolina Wilmington, told NBC News: 'It's much harder than forecasting the weather, even though the weather is a very difficult thing to forecast already.' 'There's still so much that we don't understand about what triggers eruptions and how magma moves around underneath the Earth's surface,' he added. Eruptions from Axial Seamount were recorded in 1998, 2011, and 2015, and the volcano has undoubtedly erupted numerous times prior to those events, according to Poland. In November 2024, Chadwick started investigating the volcano when he noticed its surface had swelled to nearly the same height it reached before its last eruption 10 years ago. The swelling that occurred prior to the 2015 eruption allowed Chadwick and his colleagues to predict that event. This time, the researchers' observations told them that Axial Seamount would erupt before the end of 2025. They also found that seismic activity at Axial Seamount had increased, with hundreds of earthquakes generated around the volcano per day and earthquake swarms greater than 500 per day. Wilcock said the first sign that an eruption from this volcano is imminent would be a sharp increase in the number of earthquakes around it - which the area is now experiencing. The team shared their findings at the annual American Geophysical Union conference in December 2024. This impending eruption will be a major research opportunity for Wilcock and other scientists, who plan to use a suite of high-tech instruments to monitor the eruption from start to finish. The University of Washington's College of the Environment hosts one of the largest underwater observatories in the world, comprised of networks of sensors along the seafloor and throughout the ocean waters. When Axial Seamount finally erupts, Wilcock and his colleagues will use this array to gather data and images of the event as it unfolds. Even though Axial is not a dangerous undersea volcano, the forecasting capabilities scientists have gained from studying it could help them predict eruptions from those that are. Nooner pointed out that when forecasters are wrong with their eruption predictions on land, it can cost people bother time and money through unnecessary evacuations. Watching the seamount explode will allow scientists to test out their latest forecasting models without the repercussions of getting it wrong in a populated area.
