Fastest flowing underground magma river in history discovered

Scientists have discovered a 15-km-long underground magma river beneath Iceland that reaches a flow rate of up to 7,400 cubic metres per second.

Smoke rises and lava flows from a fissure during a volcanic eruption on the outskirts of Grindavik, Iceland, February 8. Photo: AFP — Smoke rises and lava flows from a fissure during a volcanic eruption on the outskirts of Grindavik, Iceland, February 8. Photo: *AFP*

The massive underground magma river that caused recent volcanic eruptions on Iceland's Reykjanes Peninsula is flowing much faster than scientists thought, Newsweek reported on February 8. The underground magma river is about 15 kilometers long and reaches a flow rate of 7,400 cubic meters per second. According to a new study in the journal Science , this is the fastest subsurface magma flow rate ever recorded. Meanwhile, the average flow rate of the Seine River in Paris is only 560 cubic meters per second.

Underground magma rivers can transport molten rock to the Earth’s surface, allowing it to break through the crust and become a volcanic eruption. These magma rivers were responsible for the December 2023 and January 2024 eruptions on the Reykjanes Peninsula. The January eruption occurred just outside the town of Grindavík. Lava flowed into the town and burned down homes after residents had evacuated.

"In November 2023, a 15-km-long underground magma river spread beneath the town of Grindavík, Iceland, causing widespread damage and forcing the evacuation of residents. The formation of the underground magma river was followed by eruptions through fissures on December 18, 2023 and January 14, 2024, with lava flowing into Grindavík," said Sigrún Hreinsdóttir, a geodetic scientist at the institute for geology, geophysics and nuclear science GNS Science.

"Using satellite geodetic observations and seismic measurements, the team found that the underground magma river reached an extremely fast subsurface flow rate of 7,400 cubic meters per second," Hreinsdóttir added.

The study also found that pressure is not the only major cause of volcanic eruptions, but that plate pressure and the tendency of the ground to rupture are also important factors that determine the amount of magma flowing into underground rivers and the likelihood of a volcanic eruption.

“High flow rates provide valuable information about the formation of large underground magma rivers,” the team wrote. They also said that the rapid flow rate of the Reykjanes Peninsula magma river may be influenced by the low density of lava beneath Iceland, which gives it better buoyancy and allows it to flow quickly through cracks in the ground. Thus, high flow rates into underground magma rivers at other volcanoes around the world could mean they are at risk of a major eruption.

The underground magma river in the new study likely also caused a third eruption near Grindavík in the past few months, with lava starting to pour from a new fissure on February 8. The new eruption sent lava streams shooting tens of meters into the air, according to the Icelandic Meteorological Service.

Thu Thao (According to Newsweek )

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