A massive underwater volcano off the coast of Oregon has been rocked by hundreds of earthquakes a day, a sign that it could soon erupt.
Axial Seamount, the most active volcano in the Pacific Northwest, is nestled about 300 miles off the coastline and nearly a mile beneath the ocean’s surface.
Scientists have detected around 100 earthquakes per day, with recent peaks hitting 300 a day. Seismic activity is a sign magma is moving up through cracks in the volcano.
The quakes are small, typically magnitude 1 or 2, and too far offshore for humans to feel, but they’re frequent.
William Wilcock, a professor of oceanography at the University of Washington, said: ‘If this was a volcano in places where people lived, they would be evacuated.’
Experts believe pressure is building, magma is on the move, and the stage may be set for an eruption similar to the spectacular one that occurred in 2015, which saw 500 quakes per day, then 1,000, and then 2,000.
Since the magma is rising from deep within the Earth through a complicated and irregular pathway, the inflation has been less uniform and slower than in past eruptions, making this event harder to predict, Wilcock explained.
‘We think there will be some warning,’ Wilcock said. ‘But then again… volcanoes do tend to surprise people.’
The Axial Seamount has many hydrothermal vents (pictured), which are part of a complex, sprawling network
In November 2024, Oregon State University geophysicist William Chadwick noticed its surface had swelled to nearly the same height it reached before its last eruption 10 years ago
The uncertainty means that the volcano by all appearances may erupt any day now, but researchers believe it’s likelier the eruption will come by July 2026, or as late as May 2027.
When Axial Seamount does erupt, the number of underwater quakes is expected to skyrocket, rising from a hundred per day right now to as many as 10,000 earthquakes within a 24-hour period, according to Interesting Engineering.
At the heart of the volcano lies a magma chamber, a reservoir of molten rock half a mile beneath the seafloor.
As magma rises, it inflates the chamber like a balloon, stressing the surrounding rock and triggering swarms of tiny earthquakes.
Scientists have installed an array of ultra-sensitive sensors, including underwater seismometers and GPS stations, to monitor every shake and swell beneath the waves, but it’s not just the earthquakes that have them on alert.
Another warning sign is inflation, the slow swelling of the volcano as magma fills the chamber below.
In 2015, Axial Seamount was inflating at two feet per year. Now, it’s rising at about eight inches annually. That’s still significant, but less predictable.
‘This time, it’s been very erratic,’ Wilcock said. ‘It inflated quickly, then almost completely stopped. That’s what’s made this eruption harder to predict.’
If Axial Seamount does blow soon, it’ll form bulbous tubes of molten rock known as pillow lavas (pictured)
When the volcano erupted a decade ago, lava came pouring out, producing 450-foot-thick lava flows.
It also formed massive structures known as pillow lavas, bulbous tubes of molten rock that solidify quickly in seawater.
Additionally, the eruption triggered roughly 8,000 earthquakes, causing the bottom of the ocean to sink nearly eight feet.
This time, there’s also the possibility that lava could erupt from a dike, a crack that pushes magma sideways through the Earth’s crust rather than directly out of the seafloor.
Emilie Hooft, a geophysicist at the University of Oregon, said: ‘If that happens, the magma could travel laterally and erupt somewhere unexpected.’
Due to the volcano’s remote location, an eruption wouldn’t threaten human life directly, but scientists are still watching it closely.
The forecasting knowledge scientists have gained from studying the Axial Seamount could help them predict eruptions from nearby volcanos that do pose a risk to people.
Axial Seamount sits 300 miles off the coast of Oregon and more than 4,900 feet below the surface of the Pacific Ocean
Mount Rainier (pictured) sits just 240 miles from the Axial Seamount in the Pacific Northwest
For example, Washington State’s Mount Rainier is just 240 miles from the Axial Seamount.
Mount Rainier has been one of the most active volcanos in the Pacific Northwest’s Cascade Range, and a devastating eruption remains a real possibility in the near future.
Experts have said that it is only a matter of time until Mount Rainier unleashes a deadly volcanic event upon the Pacific Northwest.
This huge, active stratovolcano looms over nearly 90,000 people living in cities such as Seattle, Tacoma, and Yakima in Washington, and Portland in Oregon.
