A deep-sea volcano 300 miles off the Oregon coast is showing strong signs it may erupt soon, researchers at the University of Washington confirmed.
Axial Seamount, located more than 4,900 feet below the surface of the Pacific Ocean, is one of the most active underwater volcanoes in the Pacific Northwest.
Although it’s far from shore and little known to the public, scientists say the looming eruption presents a rare opportunity to observe one of the Earth’s most important geologic processes — and it could happen before the end of 2025.
“Over two-thirds of the Earth’s surface was formed by volcanic eruptions at these mid-ocean ridges,” said Maya Tolstoy, marine geophysicist and dean of the UW College of the Environment.
The volcano last erupted in 2015, and signs of increasing pressure beneath the seafloor have been steadily mounting.
Axial Seamount sits at the intersection of a mantle hotspot and the tectonically active Juan de Fuca Ridge, where two plates are slowly pulling apart.
That combination makes it a geological anomaly and a scientific goldmine.
The UW is home to the Regional Cabled Array (RCA), one of the largest underwater observatories in the world. Since 2014, RCA sensors have provided real-time data from the ocean floor, sending information and video from 150 instruments via fiber-optic cables stretching from the Oregon coast to Axial Seamount.
“It’s a genuine hotspot, and the volcano itself is quite large,” said William Wilcock, a UW oceanography professor. “It rises about 3,600 feet above the seafloor, and its summit is marked by a large caldera, formed by previous eruptions.”
The RCA’s constant monitoring revealed that Axial Seamount has been inflating — a sign that magma is building beneath the crust. Scientists say it has already surpassed the inflation observed ahead of the 2015 eruption.
“We’re seeing 200 to 300 earthquakes per day,” said Deborah Kelley, UW oceanography professor and director of the RCA. “We expect that to jump above 2,000 daily before an eruption, based on what we saw last time.”
Despite public concerns, experts stress the volcano poses no danger to people on land.
At such depths, there is no threat of tsunamis or regional earthquakes.
But the eruption could temporarily wipe out vibrant deep-sea ecosystems at Axial’s hydrothermal vents. These mineral-rich hot springs support unique communities of life, including microbes, tubeworms, clams, crabs, and octopuses, all thriving in the pitch-black ocean depths.
“When you get to the vent fields, you realize the volcano is an oasis of life,” Kelley said. “Even though the chemistry is similar at different vents, the microbial life can be very different — like little islands with distinct communities.”
After past eruptions, researchers observed lava flows burying entire vent areas — but life returned quickly. In 2011, animals and bacteria recolonized the area within three months.
Scientists also hope to once again observe “snowblowers” — microbial-rich fluid bursts from the seafloor seen during eruptions. These plumes contain billions of microorganisms and their waste, offering insights into how life might exist on other planets.
Axial Seamount’s rumblings also produce unusual acoustic events. As lava traps seawater beneath it, steam forms, eventually escaping in loud implosions that can be picked up by underwater microphones. While unlikely to harm marine mammals like whales, these sounds are easily detected by hydrophones.
Researchers are also watching for tidal influences on the eruption. Gravitational forces from the moon and sun affect not only ocean tides but also the Earth’s crust.
All three known Axial eruptions — in 1998, 2011, and 2015 — occurred between January and May, when the Earth is moving away from the sun.
“At high tide, the ocean’s weight presses down on the crust,” said Tolstoy. “When that weight lessens at low tide, we often see more earthquakes. It’s possible that those factors could help trigger the eruption.”
What excites scientists most is the chance to improve their ability to predict eruptions at mid-ocean ridges. If inflation continues and earthquake activity increases as expected, this event could confirm years of theoretical models — or challenge them.
“Until it happens, we won’t know which of these hypotheses are right,” Wilcock said. “Whatever it does, we’re going to learn something new.”
Whenever it does erupt, Axial Seamount is expected to produce a trove of real-time data, with thousands of earthquakes, lava flows, and seafloor collapses transmitted live for scientists — and the public — to study.
“It’s such an amazing opportunity to observe one of our planet’s most important processes,” Tolstoy said. “I think we’re all looking forward to it.”
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