Mile-Wide Underwater Volcano Poised to Erupt Off the West Coast

 

Signs of Imminent Eruption at Axial Seamount Off Oregon Coast

Things are heating up hundreds of miles off the coast of Oregon, as scientists observe growing signs of a potential eruption at the Axial Seamount, a large undersea volcano.

Located nearly a mile underwater on a geological hotspot, Axial Seamount sits on the Juan de Fuca Ridge, where the Pacific and Juan de Fuca tectonic plates are slowly spreading apart. This area, known for volcanic activity, sees molten rock rising from the Earth's mantle into the crust, creating frequent eruptions.

Recently, the volcano has shown increased signs of activity, with a surge in earthquakes coinciding with a rise in magma beneath the surface. These developments have raised concerns that an eruption could be imminent, according to researchers at the University of Washington’s Ocean Observatories Initiative Regional Cabled Array, which tracks Axial Seamount’s activity.

Axial Seamount Volcano Shows Increased Activity, Potential Eruption Imminent

Axial Seamount, an undersea volcano off the coast of Oregon, is showing signs that an eruption may be near. William Wilcock, a marine geophysicist at the University of Washington, noted that the volcano is currently experiencing several hundred earthquakes daily, a rate that is still lower than what was observed before its previous eruption.

Wilcock speculated that the eruption could occur later this year or as early as 2026, but emphasized the unpredictability of the volcano's behavior. “It could happen tomorrow,” he said, highlighting the challenges in forecasting such events.

The volcano's last eruption, in April 2015, was marked by roughly 10,000 small earthquakes in a 24-hour span. During that eruption, magma flowed from Axial Seamount for about a month, spreading approximately 25 miles (40 kilometers) across the seafloor.

Axial Seamount's magma chamber has collapsed several times, creating a caldera where a unique ecosystem thrives. Hydrothermal vents on the caldera floor release mineral-rich gases that support a diverse range of sea life, including microbes and other organisms that thrive in the extreme conditions. These vents produce "snowblower" plumes, where hot fluids rise and form white clouds of microbial life.

Debbie Kelley, director of the Regional Cabled Array, shared that despite past eruptions, the ecosystem quickly rebounded. "Life thrives in these inhospitable environments," she said. "Volcanoes are probably one of the major sources of life in our oceans," adding that this discovery has been one of the most significant in marine geology.

Although marine life in the surrounding areas, including fish, whales, and octopuses, may feel the tremors and heat from seismic activity, they are unlikely to be harmed by the eruption. People on land are also unlikely to notice any impact, according to Debbie Kelley, director of the Regional Cabled Array.

“It’s not an explosive event,” Kelley explained. “You won’t see ash clouds or anything like that above the water. It’s more like if you put a mile of seawater on top of Kilauea — you might see some fountaining, but that's about it.”

Kelley further explained that much of the planet’s volcanic activity occurs in underwater spreading centers like the Juan de Fuca Ridge, which experiences multiple smaller eruptions daily. “The magma is relatively close to the surface, about a mile deep, which is shallow compared to many land-based volcanoes, where magma can be 8 miles deep,” she said.

The behavior of magma is also influenced by its viscosity. Thicker, more viscous magma tends to create more dramatic ruptures, similar to air bubbles popping in thick tomato sauce. However, the thinner, runnier magma at Axial Seamount allows for a gentler eruption with less pressure buildup.

How to Watch

Fortunately, the relatively mild nature of Axial Seamount makes it ideal for close observation. In fact, when the volcano erupts again, the observatory plans to livestream the event to the public for the first time, according to Debbie Kelley.

Watching an undersea volcanic eruption is a challenging task. Scientists only managed to directly witness one for the first time on April 29.

About 1,300 miles (2,092 kilometers) west of Costa Rica in the Pacific Ocean, researchers working with the Woods Hole Oceanographic Institution (WHOI) were conducting a routine submersible dive to collect data on the East Pacific Rise. During their dive, they noticed that the once-lively Tica vents were no longer filled with sea life. Instead, the team discovered a "tubeworm barbeque," as WHOI Emeritus Research Scholar Dan Fornari humorously described it. They also saw flashes of orange lava seeping through the seafloor, solidifying in the cold water — a clear sign of an eruption in progress.

"This is a significant development," Fornari said. "It’s an environment that’s hard to study because it’s difficult to reach, and we need advanced technology to explore it. Ultimately, we’re observing how the planet is shaped and built through volcanic activity on the seafloor."

As Above, So Below

Unexpectedly, researchers have discovered that the timing of Axial Seamount's eruptions may not only be influenced by the activity beneath the surface, but also by forces above.

All three of the most recent eruptions — in 1998, 2011, and 2015 — occurred between January and April, coinciding with the period when Earth is moving away from the sun.

While the exact reason remains unclear, William Wilcock, a marine geophysicist at the University of Washington, suggests that the gravitational forces from the moon may play a role in triggering these eruptions.

“We don’t fully understand why this happens, but the moon's gravitational pull could be affecting the volcano,” Wilcock said.