California’s nearest active undersea volcano is about to erupt

The mysterious and highly active undersea volcano off the Pacific coast could erupt by the end of the year, scientists say.

About a mile deep in San Francisco and about 700 miles northwest, the volcano known as Axial Seamount has increased scrutiny from scientists who discovered its existence in the 1980s.

The submarine volcano is located in a darkened section of the northeastern Pacific Ocean and has erupted three times since its discovery in 1998, 2011 and 2015, according to Oregon State University researcher and volcanic expert Bill Chadwick.

Fortunately, for residents of California, Oregon and Washington, Axial Seamount does not erupt explosively, resulting in zero risk of a tsunami.

“Mounts St. Helens, Mount Rainier, Mount Hood, Crater Lake — such volcanoes have more gas and are generally explosive. Magma is more viscous,” Chadwick said. “The shaft is like a volcano in Hawaii or Iceland… There is little gas, lava is very liquid so you can get gas out without explosion.”

The destructive power of an explosive eruption is legendary. When Mount Vesuvius was blown away in 79 AD, it wiped out the city of Pompeii, ancient Rome. When the eruption erupted in 1980, 57 people died. And when the Hunga Tonga Hunga Haapai Volcano in the Tonga archipelago exploded in 2022 – a once-in-a-century event – the resulting tsunamis caused damage to the Pacific Ocean, leaving at least six people dead.

In contrast, Axial Seamount is a volcano that dissolves during an eruption. It is similar to the type of eruption of Kilauea on the island of Hawaii. As a result, the Axial eruption is not noticeable to people on land.

It’s underwater in a very different story.

William Wilcock, a professor of oceanography at the University of Washington, said the heat eruption from the eruption would rise (probably half a mile) from the seabed but would not reach the surface.

The outermost layer of lava flows quickly cools down and forms a crust, but the interior of lava flows can remain melted for a while, Chadwick said. “In some places… the lava slowly comes out and piles up. And it takes a long time for all this heat to dissipate. And with those thick streams, microbial mats can grow, making them look like snow on the landscape.”

If buried in lava, marine life could die. This also has the risk of destruction or damage to scientific equipment installed around the volcano, detecting eruptions and earthquakes. But the eruption probably won’t affect whales like whales that are “too close to the surface” that are not plagued by the eruption, Wilcock said.

Additionally, an eruption at Axial Seamount is not expected to cause a long-term, magnitude 9.0 earthquake in the Cascadia subduction zone. Earthquakes like this would likely create a devastating tsunami in Washington, Oregon and California’s northernmost coastal counties. This is because the shaft sailors are too far from their major drawbacks.

Axial Seamount is one of countless volcanoes underwater. Scientists estimate that 80% of Earth’s volcanic products (magma and lava) occur in the ocean.

Axial Seamount has attracted a strong interest from scientists. Currently, it is the most monitored underwater volcano in the world.

The volcano is partly a prolific Elta due to its location, Chadwick said. Not only do Juan de Fuca and Pacific tectonic plates perch on ridges that spread apart from each other, they also create new seabeds in the process, but the volcano is firmly planted on top of geological “hot spots.”

For Chadwick and other researchers, frequent eruptions provide an appetite-inducing opportunity to predict volcanic eruptions a few weeks or months in advance. It’s very difficult on other volcanoes. (If the scientist is wrong, it’s far less likely that anyone will get mad.)

“For many volcanoes around the world, they’re sitting, dormant for a long time, and all of a sudden they’re active. But this is always pretty active, at least during the period we’ve been studying,” Chadwick said. “If it’s not erupting, you’re ready for the next thing.”

Scientists know this. Because they found a pattern.

“During the eruption, the volcano slowly expands, meaning that the seabed will rise. And during the eruption, when magma comes out, the volcano settles and the seabed will fall,” Wilcock said.

According to Chadwick, the eruption is “like removing air from a balloon, and what we saw is that every time an eruption was caused it swelled to a similar level,” he said.

Chadwick and fellow scientist Scott Noener predicted the volcano’s 2015 eruption seven months before they noticed that the seabed was bulging very quickly and linearly. It “has made it easier to extrapolate into the future and it’s easy to reach this threshold that it reached before,” Chadwick said.

But since then it has been more difficult to predict. Chadwick began creating a forecast window in 2019, but around that time inflation began to slow down, and by the summer of 2023 it was pretty much stopped. So, ‘Who knows who’s erupting?’

However, in the second half of 2023, the seabed slowly began to swell again. Since its launch in 2024, “it’s been sort of cranking at a fairly steady speed,” he said. He and Nooner from the University of North Carolina at Wilmington made their latest eruption predictions in July 2024 and posted them. Their predictions remain the same.

“Inflation rates we expect it to erupt by the end of the year,” Chadwick said.

However, based on seismic data, the volcano is unlikely to be imminent. Scientists have not mastered predicting volcanic eruptions weeks or months ago, but they do a decent job of predicting eruptions from a few minutes to a few days ago using clues like increasing earthquake frequency.

At this point, “We’re not at the rate of earthquakes we saw before 2015,” Chadwick said. “If it explodes tomorrow, it won’t impact, but I don’t think the time will soon come.”

He warned that his predictions, although very public, are still experimental equivalents. “I think it’s that honesty, rather than looking back,” Chadwick said in November’s A. Prediction after he gave a lecture at the American Geophysical Union Conference in December.

On the bright side, he said, “I have or have the wrong alarm, it’s fine.”

If the predictions are correct, “there may be lessons that can be applied to other more dangerous volcanoes around the world,” Chadwick said. However, “more complicated” predictions of eruptions on many volcanic volcanoes on the land do not have “reproducible patterns as seen in this offshore.”

Other scientists are considering other ways to predict undersea eruptions. Scientists have begun to notice recurring patterns of temperature rise in hydrothermal holes in volcanoes in the Eastern Pacific Ocean and the timing of three eruptions at the same location over the past 30 years. “And that kind of worked,” Chadwick said.

Many fortunes have led to the scientist being located at the volcanic site known as “9 degrees north 50 minutes north on the rise in the Eastern Pacific.”

But Chadwick suspects that researchers are lucky enough to videotape the eruption of axle sailors.

Scientists are funded by the National Science Foundation, a sensor system run by the University of Washington, so taking the time to get there is a challenge.

“They don’t last that long, so you have to be in the right place at the right time to catch an eruption. The shaft stuff probably lasts for a week or a month,” Chadwick said.

And it is difficult to get a vehicle or submarine that operated remotely with a ship to capture images. Such vessels are generally well before, perhaps a year or a half away, and projects are strictly scheduled.

Chadwick is expected to last go to the volcano in 2024 and will be out next in the summer of 2026. If his predictions are correct, the sailors on the shaft would have already erupted.