What could happen when huge underwater volcano erupts as scientists say it could be 'any day now'

A number of things could happen when a massive underwater volcano off the coast of the US erupts, which could be 'any day now'.

Scientists have warned of the impact that could be caused by the sleeping giant known as the Axial Seamount, which is around 300 miles off the coast of Oregon, on the American west coast.

This is despite the fact that it lies 5,000 feet below the Pacific Ocean's surface.

The underwater volcano has the power to change the face of the sea floor if it erupts and spews lava, which it also did in 1998, 2011 and 2015.

Experts have warned that another eruption is on the way after spotting some inflation on the sea floor, the sign of an imminent eruption, as well as an increase in seismic activity.

There's no set date, while experts have said it could be 'any day now'. But what were to happen, exactly, if the volcano were to erupt - would anyone on land be affected?

The underwater volcano could cause an earthquake (Schmidt Ocean Institute)

Marine impact

Arguably, the biggest changes we would see would be in water temperature and gas composition caused by the release of magma and other materials, which would alter the surrounding marine life and its environment, either disrupting or killing certain species.

However, some species may actually thrive with the new heat sources on offer, and with the chemistry changing after the eruption following the release of the likes of sulfur dioxide.

Possibility of Earthquakes or Tsunamis

As usually found with volcanic eruptions, seismic activity would come with the eruption.

Axial Seamount already produces a large amount of this, with it being located on the Juan de Fuca plate, and while some shaking is expected, it is said that it will mostly be contained underwater.

Tsunamis on the other hand, are far less likely to be caused, though if the eruption was powerful enough to cause the Seamount's summit to collapse or a large amount of material was spewed out quickly enough, then one would be possible.

It would affect the states of Oregon and California if one were to occur - again, highly unlikely.

The eruption of the Axial Seamount would primarily affect surrounding marine life (Susan Merle/Oregon State University)

Impact on humans

It is expected that due to it being so far off any dry land and being over a kilometre underwater, the eruption of the Axial Seamount will have no direct threat to humans.

However, submarine cables or research instruments in the surrounding area could be damaged, such as those on the Ocean Observatories Initiative.

As the eruption is expected any day though, scientists will be able to get a real-time look at seafloor volcanism due to the technology in place to monitor the eruption.

Long-term effects

The eruption could reshape the seafloor, altering vent ecosystems and making new lava fields, but it could help scientists get a better understanding of mid-ocean ridge volcanoes in general.

As with all earthquakes and seismic activity, it would also give experts an insight into how our planet's crust forms at spreading centres.

There is a low chance of the eruption affecting humans (University of Washington/OOI Regional Cabled Array)

Scientists' claims

William Wilcock, a marine geophysicist and professor at the University of Washington, said: "Over time, the volcano inflates due to the buildup of magma beneath the surface,

"Some researchers have hypothesised that the amount of inflation can predict when the volcano will erupt, and if they’re correct it’s very exciting for us, because it has already inflated to the level that it reached before the last three eruptions.

"That means it could really erupt any day now, if the hypothesis is correct."

Deborah Kelly, a professor in the UW School of Oceanography and director of the Regional Cabled Array added to this point, too.

She explained: "We’re seeing 200 to 300 earthquakes per day, with some spikes around 1,000 per day due to the tides. 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."

Marin geophysicist spoke of the eruption getting closer, claiming: "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.

"What will be really interesting to see is whether those factors also affect the likelihood of an eruption by putting additional stress on the magma chambers."