The Axial Seamount, a large underwater volcano about 300 miles off the Oregon coast and nearly a mile below the ocean’s surface, is showing signs that it might erupt again soon. It last erupted in 2015, covering the seafloor with a mile-long stretch of lava. Now, scientists are seeing the same warning signs that showed up before previous eruptions.
This volcano slowly swells over time as magma builds up underneath it. According to William Wilcock, a geophysicist at the University of Washington, the volcano has inflated to the same level it reached before its last three eruptions. If researchers are right, that means it could erupt any day now but no one can say exactly when.
One major clue that an eruption may be near is the increasing number of earthquakes happening around the Seamount. Right now, there are 200 to 300 small quakes each day—sometimes even up to 1,000 on days when tides are shifting. If that number jumps to 2,000, scientists say an eruption is probably imminent.
Maya Tolstoy, another marine expert, explained that even small changes in the ocean’s weight during tides can affect the stress levels in the Earth’s crust, potentially triggering an eruption. This makes the situation around the Seamount especially unstable right now.
Axial Seamount has erupted at least twice before—in 2011 and 2015—but scientists still don’t fully understand how underwater volcanoes behave, mostly because they’re so hard to observe in real time. These eruptions happen in deep water and out of sight, making research more difficult.
Despite their dangers, underwater volcanoes like Axial create unique habitats for sea life. They can help bring food up from deep currents and host strange ecosystems around hydrothermal vents, where heated water from inside the Earth bursts into the ocean. These vents are like underwater oases, full of microbes and animals that thrive in extreme conditions. But eruptions can destroy these habitats in an instant.
In 2011, one of these vent areas was completely wiped out by lava, killing everything in its path. But when scientists returned just three months later, life was already starting to come back—proving how tough and adaptable these deep-sea communities can be.
When magma rises through the Earth and reaches the surface, it releases gases. On land, this can cause explosive eruptions. But underwater, the pressure of the ocean changes how the eruption happens. The cold water cools the magma quickly, turning it solid in a process called “quenching.”
Axial Seamount was formed by a hotspot—basically a deep part of the Earth’s mantle where molten rock pushes upward. As the Earth’s crust moves, the hotspot stays in place, creating a chain of volcanoes over time. Most of Earth’s volcanic activity actually happens deep in the oceans, not on land, and Axial is a key example of that.
Even with all this monitoring and research, no one has ever seen an eruption at this particular underwater mountain chain as it happens. Scientists hope to learn more if Axial erupts soon, but for now, all they can do is watch, wait, and study the signs.
