Iceland Volcano Update: New Eruption Warning Issued

The threat of a new eruption has emerged on Iceland's Reykjanes Peninsula as magma pooling under the surface of the Earth's crust continues to accumulate after being dramatically discharged from a fissure last week.

The Icelandic Meteorological Office said on Wednesday that the land around a geothermal power plant at Svartsengi was rising at a rate "very similar to what it was before the eruption on December 18."

When the eruption occurred, the crustal uplift reduced by nearly 3 inches as pressure was released, having risen by nearly 14 inches since the magma intrusion formed on November 10. At the time, officials said it was "too early to determine if magma will continue to accumulate" beneath the surface there.

However, they said on Wednesday that the recent land rise suggested magma was still accumulating under Svartsengi and was "likely to lead to another magma flow and also an eruption." Around 730 earthquakes have been recorded in the region since December 22, most at a depth of around 4 kilometers (2.5 miles) as magma pushes up into the crust.

A horizontal intrusion of magma—around 6 miles in diameter—has been building under the peninsula since November 10, and is thought to be channeling magma into a vertical intrusion—estimated to be around 9.3 miles long—near the coastal fishing town of Grindavik.

Swarms of seismic activity led to anticipation that a volcanic event was set to occur, with magma likely propagating to the surface through the vertical dike. That occurred on Monday, December 18, with lava shooting up to 650 feet into the air from five fissures in the initial phase of the eruption.

As of December 21, the volcanic activity from the fissures—which sit around 1.7 miles from Grindavik—had ceased, but the Icelandic Met Office warned that a similar event could occur due to the building magma.

It said that around 11 million cubic meters (2.9 billion gallons) of magma were calculated to have propagated from the horizontal intrusion to form the vertical dike, which resulted in an eventual eruption.

Officials said at the current rate, "it will take about two weeks for the same volume to accumulate in the magma chamber," but cautioned that "there is great uncertainty as to when the pressure in the magma chamber will be high enough to trigger a new magma injection."

While magma could propagate from the horizontal intrusion into other parts of the crust under the Reykjanes Peninsula, the Icelandic Met Office said that "the most likely source area for the next eruption is between [the] Stóra-Skógfell and Hagafell [mountains]," where the fissures opened up on December 18.

"There is still a chance of an eruption that increases with each passing day," it warned.

Ben Edwards, an American volcanologist who has visited the Reykjanes Peninsula multiple times, previously told Newsweek that the eruption could mark the start of over a century of volcanic activity in the region.

His remarks came after a leading Icelandic volcanologist told Newsweek that after a dormant period, the activity leading up to the eruption could mark the start of an "intense" period of "rifting and volcanism" on the peninsula.

While Haraldur Sigurdsson, an emeritus professor of geophysics at the University of Rhode Island, expressed hopes following the eruption for a brief reprieve from volcanic activity, both he and Edwards noted much of Iceland's infrastructure—including the capital Reykjavík—is located in the region.