Warning issued over mile-long volcano off US mainland that could erupt this year

The so-called most active volcano in the Pacific Northwest is looking like it'll erupt again this year, as scientists have been keenly studying the mile-long structure due to its heightened levels of activity.

Volcanoes can be some of the most dangerous natural occurrences across the Earth, and reports of hundreds of subglacial volcanoes trapped across Antarctica show worrying signs for the future of the area.

The destructive capabilities of volcanoes are present throughout history too, as you only have to look at Mount Vesuvius in Pompeii as a clear example as archaeologists are still only just discovering things hidden underneath the ash and rubble.

That's why warnings surrounding what many scientists have branded the most active volcano in the Pacific Northwest to be initially concerning - although it's thankfully not as dangerous as you might think.

Axial Seamount is found off the coast of the Pacific Northwest, and stretches over a mile wide (Susan Merle/Oregon State University)

Axial Seamount is around 280 miles (460 kilometers) off the coast of Washington and Oregon in the Pacific Northwest, and stretches around a mile wide and roughly 3,600 feet (1,100 meters) from the sea floor, as reported by Indy 100.

It's proven to be incredibly active - especially in the last decade and a half - registering eruptions in 1998, 2011, and most recently 2015.

Scientists now predict that a decade later Axial Seamount could be scheduled to erupt again, as both swelling and magma build-up has been detected inside of the underwater volcano.

It's indicated that this swelling has reached around 95% of the amount that caused it to erupt in 2015, and Bill Chadwick, Marine Science Research Professor at Oregon State University, has explained the interest in Axial Seamount, speaking to KOIN:

"If it's not erupting, it's inflating and getting ready for the next one. And that's why we're kind of monitoring what's happening to it all the time [...] And in the last year, especially, the number of earthquakes, which is also monitored by this cable observatory, has really increased.

"So, all these signs are pointing toward the final stages of buildup to the next eruption."

'Seamount' or underwater volcanoes don't have the same destructive qualities associated with their eruptions, and are more akin to 'deflated balloons' (K. Lynn/USGS/Anadolu via Getty Images)

Thankfully, while eruption appears to be imminent, it doesn't carry the same level of danger as a typical land-bound volcano. As opposed to the violent and often devastating eruptions you'll likely be aware of, submarine volcanoes are akin to that of a balloon deflating.

Chadwick outlined to OregonLive: "Axial's summit inflates like a balloon as magma is supplied from below and stored in the reservoir beneath the volcano summit. The balloon keeps getting bigger and bigger.

"And at some point, the pressure becomes too great and the magma forces open a crack, flowing to the surface. When that happens, the seafloor subsides as the 'balloon' deflates."

It's still likely to make quite the show when it does eventually erupt though, but thankfully without any of the suboptimal risks you'd typically associate with something of this kind.