Axial Seamount, a massive volcano off Oregon’s coast, is swelling and expected to erupt by the end of 2025

A huge underwater volcano, Axial Seamount, located off the coast of Oregon, is poised to erupt later this year, experts warn. Situated about 300 miles from the US northwestern coast, the volcano rises 1,100 metres from the seafloor and has been one of the most active undersea volcanoes in the world. Scientists are closely monitoring its activities as new data suggests it is nearing an eruption, which would mark its fourth in the past three decades.

In November 2024, research revealed that the surface of Axial Seamount had swollen to 95% of the height it reached before its last eruption in 2015, indicating an intense build-up of magma beneath. This increase in size, along with an uptick in seismic activity, led geologists William Chadwick from Oregon State University and Scott Nooner from the University of North Carolina Wilmington to predict that an eruption could occur by the end of 2025.

The two experts have analysed the rate of inflation at Axial over the last six months and noted that seismicity—earthquakes that indicate magma movement—has been moderating. While Chadwick cautions that an eruption is not imminent, he insists that the volcano can’t keep swelling forever. The volcano’s surface is fully “re-inflated,” an indication that it’s ready to release the built-up pressure in the form of lava.

Axial Seamount differs from land-based volcanoes in that its eruptions are not explosive. The immense pressure of the surrounding ocean water prevents an explosive release, resulting in a steady, non-threatening flow of lava across the seafloor. Previous eruptions at Axial have not posed any immediate danger to human life, and scientists believe the upcoming eruption will not either, though the area’s ecosystems will be impacted.

The volcano, which has been actively monitored by cabled systems and underwater sensors, is likely to erupt in a fashion similar to previous events. As Chadwick describes, an eruption at Axial Seamount resembles the deflation of a balloon, releasing a consistent stream of lava rather than the violent eruptions that we associate with land volcanoes. The regularity of its eruptions suggests it has a predictable pattern, and while an eruption is certain, it will likely pose no direct threat to coastal populations.

Even so, scientists are not ruling out the possibility of an earlier-than-expected eruption. With seismic activity on the rise, the next few months will be critical for monitoring Axial’s behaviour. The last eruption in 2015 saw the release of approximately 5 million cubic metres of lava, significantly altering the surrounding seafloor and affecting nearby hydrothermal vents. As one of the most studied underwater volcanoes in the world, Axial continues to offer critical insights into the dynamics of oceanic eruptions and the geology of the Pacific Ocean.

Axial Seamount’s potential eruption highlights the growing need for vigilance in monitoring underwater volcanoes, which, though less explosive than their land-based counterparts, can still have profound environmental consequences. As we await the eruption, the scientific community continues to gather data and improve our understanding of these deep-sea giants.