What underwater volcano eruptions look like as scientists warn one off US coast set to explode imminently

A scientist has explained what we can expect to happen when an underwater volcano erupts, as one off the US coast is expected to blow imminently.

Situated off the Pacific coast of America, around 300 miles off the coast of Oregon and Washington state, is Axial Seamount.

Known as a submarine volcano, Axial Seamount sits around 5,000 feet below the ocean's surface and is relatively active, having erupted in 2015, 2011 and three times in 1998.

A decade on from the last time magma exploded from the underwater volcano and it would appear that Axial Seamount is likely to erupt imminently, with scientists noting increased seismic activity in the region.

So what happens when an underwater volcano erupts — and are we in any danger?

What happens when an underwater volcano erupts?

Location of Axial Seamount in regards to the western USA (Google Maps)

Thanks to stories about the citizens of Pompeii, before and after images of Mount St Helens and dramatisations of what a Yellowstone eruption would look like (thanks, 2012) most of us will have grown up with a healthy fear of volcanic eruptions.

However, it would appear that submarine volcano eruptions are rather less dramatic.

Like volcanoes on land, these underwater fissures are caused by magma which forms along tectonic plates. When they erupt magma pours out of the volcano and onto the seafloor.

In some cases submarine volcanoes can even go on to become islands themselves, with examples being found near the countries of Hawaiʻi, Indonesia and Iceland.

Will an eruption at Axial Seamount cause disruption?

When most people think of volcanic eruptions they're likely to picture chaos, however this isn't likely to be the case with Axial Seamount.

"There's no explosion or anything, so it would really have no impact on people," volcanologist William Chadwick explained to GB News

Revealing more about what the eruption process would look like, University of Washington marine geophysicist William Wilcock said: "[The eruption] period lasts about an hour, and then the magma reaches the surface.

Axial Seamount could erupt anytime between now and next year, judging by increasing activity (Schmidt Ocean Institute)

"The seismic activity dies down pretty quickly over the next few days, but the eruption will continue slowly for about a month."

The Axial Seamount can even provide a 'fascinating' source of research for scientists, with University of North Carolina's Scott Nooner noting to NBC: "On land, if you make a forecast that a volcano is going to erupt in a week or a month and you’re wrong, you’ve cost people a lot of money and time and worry.

"But we don’t have to worry about that at Axial Seamount because these eruptions don’t impact anyone."

Researchers are continuing to monitor Axial Seamount (Susan Merle/Oregon State University)

When could Axial Seamount erupt?

There's not an exact timeframe on when we can expect the underwater volcano to blow its top, but seismic activity in the region points to it being anytime from now to early next year.

"I would say it was going to erupt sometime later (this year) or early 2026, but it could be tomorrow, because it's completely unpredictable," Wilcock concluded.