Things are heating up off the coast of Oregon, where scientists are monitoring a large underwater volcano showing signs of a potential eruption.
Axial Seamount, located nearly a mile (1.4 kilometers) beneath the surface, sits on a geological hotspot where molten rock from Earth’s mantle rises into the crust. This type of volcanic activity is common on the seafloor, but Axial Seamount’s unique location on the Juan de Fuca Ridge adds to the tension. The Juan de Fuca Ridge is where two massive tectonic plates—the Pacific and Juan de Fuca plates—are slowly pulling apart, creating pressure beneath the Earth’s surface.
Recent seismic activity has increased significantly, with frequent earthquakes indicating that the volcano is inflating as it fills with more magma. Researchers from the National Science Foundation’s Ocean Observatories Initiative Regional Cabled Array, operated by the University of Washington, are closely monitoring the activity, suggesting that an eruption could be imminent.
At present, there are a couple hundred earthquakes each day, but that’s still far fewer than what was recorded before the last eruption,” said William Wilcock, a marine geophysicist and professor at the University of Washington’s School of Oceanography, who has studied Axial Seamount extensively.
“I would estimate the eruption could happen later this year or early 2026, but it could occur tomorrow too, because it’s completely unpredictable,” he explained.
What happens during an eruption?
The last eruption at Axial Seamount occurred in April 2015, when the team recorded nearly 10,000 small earthquakes in just 24 hours, a pattern that’s expected to repeat during the next eruption, Wilcock noted.
During that eruption, magma — molten rock from beneath the Earth’s surface — flowed from the volcano for a month, spreading over 25 miles (40 kilometers) across the seafloor.
Axial Seamount’s magma chamber has also collapsed multiple times in the past, forming a massive crater known as a caldera. This unique feature serves as a habitat for thriving sea life, sustained by the mineral-rich gases escaping through hydrothermal vents, akin to underwater hot springs. These vents emit hot fluids rich in microbes and waste, which bubble up in white plumes, referred to as “snowblowers.”
Despite the devastation caused by lava flows in previous eruptions, the ecosystem around these vents has rebounded remarkably quickly, often flourishing within just three months, said Debbie Kelley, director of the Regional Cabled Array.
“This is one of our biggest discoveries,” Kelley, a professor of marine geology and geophysics at the University of Washington, commented. “Life can thrive in such extreme conditions, and volcanoes are likely one of the major drivers of life in our oceans.”
While marine life in the area, including fish, whales, and octopuses, may experience the heat and seismic tremors of the volcanic activity, they are unlikely to be harmed. People on land will probably not notice the eruption at all, according to Kelley.
“It’s not a very explosive event. You won’t see ash clouds or anything above water,” she explained. “It’s more like if you had a mile of seawater on top of Kilauea — you might see some fountaining, but that’s about it.”
In fact, most volcanic activity occurs in underwater spreading centers, such as the Juan de Fuca Ridge, where small eruptions take place almost daily, Kelley noted.
“The magma is quite close to the surface — about a mile beneath it — which is very shallow compared to many land volcanoes where magma can be 8 miles (12.9 kilometers) deep,” Kelley explained. The magma’s viscosity, or thickness, also plays a crucial role in the eruption. Like thick tomato sauce on a stove, the higher-viscosity magma experiences more dramatic ruptures, whereas Axial Seamount’s thinner, runnier magma results in a less explosive eruption.
How to Watch
The relative mildness of Axial Seamount makes it an ideal candidate for close human observation. In fact, when the volcano erupts again, the observatory plans to publicly livestream the event — a first for the research team, according to Kelley.
Watching an undersea volcanic eruption, however, is no simple task. The first direct observation of such an event occurred on April 29, when researchers, in collaboration with the Woods Hole Oceanographic Institution (WHOI), were on a routine submersible dive to collect data on the East Pacific Rise. During the dive, they noticed that the once-vibrant Tica vents were no longer home to thriving sea life. Instead, the team found what WHOI Emeritus Research Scholar Dan Fornari described as a “tubeworm barbecue.” They observed flashes of orange lava leaking through the seafloor and solidifying in the frigid water, confirming that an eruption was underway.
“It’s quite a significant development,” Fornari remarked. “This is a very understudied environment because it’s so difficult to reach, and we rely on advanced technology to explore it. At the core of it, we are witnessing how this planet is constructed and reshaped by volcanism beneath the sea.”
As Above, So Below
Surprisingly, close observation of Axial Seamount has revealed that the timing of its eruptions isn’t solely determined by the magma building up beneath the surface — it may also be influenced by factors above.
All three of the most recent eruptions — in 1998, 2011, and 2015 — occurred between January and April, during the period when Earth is moving away from the sun.
“I don’t think we fully understand why that is, but it could be related to the gravitational forces from the moon influencing the volcano,” Wilcock explained. These lunar forces, which affect tides on Earth, may play a role in triggering volcanic activity by exerting subtle pressure on the Earth’s crust. However, this connection remains an area of active research and intrigue.
The moon orbits Earth every month, and its gravitational pull causes ocean tides to rise and fall, creating pressure variations on the seafloor. As Axial Seamount’s magma chamber accumulates more magma, these tidal pressure changes begin to have an effect. The gravitational forces, particularly at high tide, exert additional stress on the caldera—the crater formed by previous eruptions. This pressure intensifies the seismic activity, with more frequent earthquakes gradually pushing the magma chamber toward its breaking point, according to Kelley. These subtle, lunar-driven forces could be contributing to the eventual eruption.
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