Scientists warn huge underwater volcano could erupt ‘any day now’

Deep beneath the surface of the Pacific Ocean, some 300 miles off the Oregon coast, a colossal underwater volcano is showing signs that it may soon awaken. Known as the Axial Seamount, this submerged giant lies nearly a mile below sea level—far from sight, yet closely watched by scientists who say it could erupt “any day now.”

Unlike the dramatic eruptions we associate with volcanoes on land, undersea eruptions are quieter, harder to detect, and often go unnoticed by the public. But they are no less significant. When the Axial Seamount last erupted in 2015, it reshaped the seafloor, disrupted deep-sea ecosystems, and offered scientists a rare window into the inner workings of Earth’s crust. Today, researchers monitoring the site are detecting familiar warning signs: inflation of the seafloor, a rise in earthquake activity, and subtle shifts that suggest magma is building pressure beneath the ocean bed once again.

The Silent Build-Up Beneath the Surface

Far beneath the Pacific Ocean’s surface, about 300 miles off the coast of Oregon, the Axial Seamount is showing signs that it could erupt imminently. Situated nearly 5,000 feet below sea level, this submarine volcano is out of sight but not out of scientific scrutiny. It last erupted in 2015 and has a well-documented history of reshaping the ocean floor during its eruptions in 1998, 2011, and 2015. Now, researchers are seeing familiar warning signs that it may be on the verge of another event.

Central to this concern is the inflation of the seafloor—a telltale sign of magma accumulating beneath the crust. As the magma chamber fills, it causes the surface above to bulge, much like a balloon. “Over time, the volcano inflates due to the buildup of magma beneath the surface,” explains Dr. William Wilcock, a marine geophysicist at the University of Washington. He and other researchers note that the Axial Seamount has already reached, and in some measures surpassed, the inflation levels recorded prior to its last three eruptions.

But inflation is just one part of the equation. Seismic activity—specifically the frequency and intensity of earthquakes—is also under close watch. According to Dr. Deborah Kelley, director of the Regional Cabled Array and professor at the UW School of Oceanography, current seismicity is relatively moderate, averaging 200 to 300 quakes per day. “If what we learned in 2015 is correct, I would expect to see more than 2,000 per day for a few months before the eruption,” she said.

Interestingly, some of this seismic activity may be tied to ocean tides. Marine geophysicist Dr. Maya Tolstoy notes that tidal fluctuations subtly affect the Earth’s crust. “At high tide, the weight of the ocean presses down on the crust, and when that weight is ever so slightly decreased at low tide, the number of earthquakes increases,” she explained. This interplay between tides and seismic events could play a role in triggering an eruption, adding complexity to scientists’ forecasting efforts.

Despite the dramatic nature of these developments, the public is not in danger. The Axial Seamount’s remote location and underwater setting mean its activity, while significant to scientists, remains virtually undetectable to those on land. Still, this impending eruption is more than a geological curiosity—it’s a rare chance for scientists to learn more about the hidden dynamics of Earth’s oceanic crust.

Monitoring a Volcano in the Deep Sea

Tracking the behavior of a volcano nearly a mile beneath the ocean surface presents unique scientific and technological challenges. Unlike land-based volcanoes, which can be monitored with satellite imagery and on-site instruments, underwater volcanoes like the Axial Seamount require a far more intricate system of observation. Fortunately, the Axial Seamount is one of the most closely monitored submarine volcanoes in the world, thanks to pioneering ocean observatory networks and decades of research.

Central to this effort is the Regional Cabled Array, a part of the National Science Foundation’s Ocean Observatories Initiative. This seafloor observatory, operated by the University of Washington, links underwater instruments to shore via high-powered fiber-optic cables. These cables provide real-time data on seismic activity, temperature, pressure, and chemical changes—allowing scientists to detect and analyze early signs of volcanic unrest without the need to deploy ships or remotely operated vehicles every time.

Dr. Deborah Kelley, who directs the project, emphasizes the importance of such systems in bridging the information gap between eruptions. “We’re seeing, in real-time, how these systems behave, from inflation of the seafloor to earthquake swarms that precede an eruption,” she explained. In 2015, this network was key in capturing the full arc of volcanic activity, from the initial inflation to the explosive event and the subsequent collapse of the seafloor.

One of the most valuable insights from previous eruptions has been the recognition of predictive patterns. As Dr. William Wilcock noted, the repeatability of the inflation levels before each of the last three eruptions suggests a measurable correlation between magma buildup and eruption timing. If proven consistent over time, this would mark a significant step forward in understanding how submarine volcanoes behave—and possibly, in forecasting future eruptions with greater precision.

What Makes Underwater Eruptions Unique

Unlike their land-based counterparts, underwater volcanic eruptions unfold under a cloak of water pressure, extreme depth, and often, total darkness. These conditions not only mask eruptions from casual observation but also significantly alter the way volcanic activity manifests and impacts the surrounding environment. Understanding these differences is crucial to interpreting the current signs at Axial Seamount—and to advancing the broader field of marine geology.

One of the defining features of submarine eruptions is the immense water pressure at depth. At nearly 5,000 feet below sea level, the Axial Seamount’s magma is constrained by pressures over 150 times greater than at the surface. This pressure prevents explosive degassing, the violent release of gases that typifies many land eruptions. Instead, magma tends to ooze out more slowly, forming pillowed lava flows that spread across the seafloor in bulbous, mound-like shapes. These flows can cover vast areas and even reshape hydrothermal systems, as was documented during the 2015 eruption.

This lack of explosive activity might seem to make underwater eruptions less dramatic—but they are no less transformative. In 2015, the Axial Seamount’s eruption caused the seafloor to drop by nearly 8 feet, drastically altering the topography and disrupting local ecosystems. Hydrothermal vents—cracks in the seafloor that emit superheated, mineral-rich water—were buried or newly formed, which in turn disrupted the lifeforms that depend on them. These ecosystems, often based on chemosynthesis rather than photosynthesis, are among the most unique and least understood biological communities on Earth.

Another distinguishing factor is the invisibility of warning signs. While land volcanoes may show visible smoke, ash, or lava, underwater volcanoes rely on indirect signals such as seismic tremors, ground deformation, and temperature anomalies. The very signs now evident at Axial Seamount—inflation, increased microearthquake activity, and subtle geochemical shifts—are only accessible due to highly sensitive instrumentation installed on the seafloor.

Environmental and Scientific Impacts of an Eruption

Though Axial Seamount poses no immediate threat to human populations, its next eruption could have far-reaching implications—both ecologically and scientifically. These underwater events serve as powerful reminders of the Earth’s dynamic nature, offering a front-row seat to geological processes that typically unfold over millennia. But they also present ecological disruptions and research opportunities that ripple well beyond the eruption itself.

One of the most immediate impacts is on hydrothermal vent ecosystems, which thrive around the superheated fissures in the ocean floor. These ecosystems support unique life forms—such as tubeworms, vent crabs, and extremophile bacteria—that rely on chemical energy rather than sunlight. When lava flows over these vent fields, it can bury them completely, instantly wiping out entire communities. Conversely, new vents formed by volcanic reshaping can foster colonization and ecological succession, providing scientists with rare case studies in resilience and adaptation.

The 2015 eruption, for example, allowed researchers to document how vent communities recover over time and how species redistribute themselves after such disturbances. “It’s like hitting a reset button on a complex ecosystem,” Dr. Deborah Kelley noted in earlier research. These changes help marine biologists better understand not just adaptation in extreme environments, but also broader questions about biodiversity and evolution in isolated ecosystems.

Volcanic activity also influences chemical and thermal balances in the ocean. New lava releases gases like carbon dioxide, sulfur, and methane into the water, temporarily altering its chemistry. Although the ocean’s vastness dilutes these emissions, localized changes can affect pH levels and microbial communities. Over longer periods, this data feeds into global models of ocean circulation and climate interactions—areas of growing concern as climate patterns become more volatile.

Why It Matters—And What Comes Next

While the Axial Seamount lies far from human settlements, its activity is anything but irrelevant. In a world increasingly affected by climate shifts, ocean changes, and natural disasters, understanding the forces shaping the seafloor is more than academic—it’s essential. Submarine volcanoes like Axial Seamount play a crucial role in Earth’s geodynamics, impacting everything from ocean chemistry to plate tectonics and even global climate patterns over time.

The current signs—rising magma, seafloor inflation, and a growing cadence of microearthquakes—place Axial Seamount on the cusp of transformation. But perhaps the most remarkable aspect of this moment is not the potential eruption itself, but what it represents: a rare opportunity to witness and learn from a powerful geologic process as it unfolds in real time.

For scientists, it’s a chance to test hypotheses, refine models, and expand the limits of underwater observation. For the public, it’s an invitation to understand the planet in deeper, more interconnected terms. Events like this underscore the importance of sustained investment in ocean science and infrastructure, such as the Regional Cabled Array and similar observatories around the world. These systems not only enhance our understanding of natural hazards, but also allow for earlier warning and more resilient responses—benefits that extend to earthquake zones, coastal cities, and climate forecasting alike.

There’s also a quiet, humbling takeaway: much of the Earth remains beyond our view, yet vibrantly alive and evolving. Beneath miles of water, volcanoes build new land, reset ecosystems, and release the Earth’s inner heat in ways that subtly shape the world we live in. The more we know, the better equipped we are to care for that world—and to face the complex challenges ahead with knowledge, preparation, and awe.