Deep below the surface of the northeastern Pacific Ocean, a massive undersea volcano is quietly swelling. Hidden under 1,400 meters of water and located nearly 300 kilometers off the coast of Oregon, Axial Seamount has long captured the attention of volcanologists. Now, subtle shifts in pressure and consistent tremors suggest the site may be nearing another eruption — the first since 2015.
Axial is not a stranger to such activity. It has erupted three times in the last few decades — in 1998, 2011 and 2015 — each time releasing slow-moving lava flows rather than explosive outbursts. Unlike well-known stratovolcanoes like Mount St. Helens, this underwater formation releases fluid lava with low gas content, which allows it to inflate gradually before venting magma in what scientists describe as a “balloon-like” cycle. These dynamics make it one of the most predictable volcanic systems on Earth.
A Laboratory Beneath the Waves
Axial Seamount is perched at a volatile geological intersection — the meeting point of the Juan de Fuca and Pacific tectonic plates. The volcano rises over 1,000 meters above the ocean floor and rests atop the Juan de Fuca Ridge, a seismically active submarine mountain range. The site is also believed to be fed by a persistent hotspot, further fueling its volcanic behavior.
Scientists have tracked Axial’s movements for decades, but the research effort intensified after the installation of the Regional Cabled Array in 2014. Operated by the University of Washington and funded by the National Science Foundation, this fiber-optic network has transformed Axial into the most closely monitored submarine volcano in the world. More than 140 instruments embedded in the seafloor now record pressure changes, seismicity, temperature, and seafloor deformation in real time.
According to data released in July 2024, inflation has been steadily increasing since the beginning of the year. The observations have led Bill Chadwick, a volcanologist at Oregon State University, and his colleague Scott Nooner of the University of North Carolina Wilmington, to forecast the possibility of another eruption before the end of 2025.
“The volcano acts like a balloon,” Chadwick told NBC News, “and eventually it reaches a threshold and empties itself.” The pair had previously predicted the 2015 eruption with a lead time of seven months, a rare success in a field often hampered by uncertainty.
When Lava Reshapes the Seafloor
The eruptions themselves are not marked by dramatic plumes or shockwaves. Instead, lava oozes across the seabed in thick, dense flows that alter the topography. The 2015 eruption left deposits up to 140 meters thick in some areas — equivalent to about two-thirds the height of Seattle’s Space Needle. As the lava cools rapidly in contact with seawater, it forms bulbous, rounded formations known as pillow lavas, characteristic of submarine volcanic activity.
These changes have long-term consequences for the geology of the region, but their impact remains mostly confined to the ocean depths. The summit of Axial is too deep to trigger tsunamis, and any eruption would likely go unnoticed from the surface. Chadwick noted that even a nearby ship wouldn’t detect the event without instruments.
Extreme Life in Extreme Heat
Axial’s influence extends beyond geology. Along its flanks, hydrothermal vents discharge superheated water — reaching temperatures above 370°C — into the cold surrounding sea. These vents create an environment where bacteria thrive by converting minerals into energy through chemosynthesis. This microbial life forms the base of a unique ecosystem populated by tube worms, crustaceans, and fish that have adapted to the pitch-black, high-pressure conditions.
The lava flows can temporarily bury these vent systems, disrupting the ecosystem. But over time, new vents typically emerge as magma continues to heat the subsurface. This ongoing cycle of destruction and renewal has turned Axial into a natural observatory for studying both volcanic activity and life under extreme conditions. For biologists and geologists alike, the volcano offers a rare glimpse into one of the planet’s most remote and dynamic environments.
