Ocean hidden under sea floor could be the cause of ‘slow motion’ earthquakes

A hidden underground ocean could be causing ‘slow motion’ earthquakes, according to scientists.

Though it sounds like a conspiracy theory, experts believe that the water is part of a vast volcanic region that was formed over 125 million years ago.

If that wasn't weird enough, the water’s movement has resulted in mysterious earthquakes in the country's northern region.

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Puzzled by the so-called ‘slow motion earthquakes’, which have been increasing, a scientist from the University of Texas Geophysics department set out to investigate.

Though the quakes had caused relatively little damage, their occurrence close to the cost of Gisborne was a concern for Andrew Gase.

It was then that he discovered the ‘hidden ocean’ at the bottom of the sea floor, while surveying a volcanic site.

Now covered by water, the scientist used a boat towing a 3D seismic sensor to gain deep insight into the area – with a shocking revelation.

Andrew Gase

Having built a model of the area, drill core samples revealed that water had become trapped among the thick sediment.

It was puzzling for the expert, with Gase explaining: “Normal ocean crust, once it gets to be about seven or 10 million years old should contain much less water.”

However, these surrounding rocks were 10 times as old – potentially formed 125 million years ago after a dramatic eruption forced lava to the Earth’s surface.

The resulting plume is thought to have covered an area bigger than the US.

While researchers are still investigating, the breakthrough might explain one of New Zealand’s weirdest phenomena.

The country experiences ‘slow motion’ earthquakes, also known as slow slip events – with the seismic event happening over several days.

It’s thought that the Pacific tectonic plate could play a part in producing these strange events, with the Hikurangi Subduction Zone having more trapped water than other regions.

Continuing, Gase said in statement: “We can't yet see deep enough to know exactly the effect on the fault, but we can see that the amount of water that's going down here is actually much higher than normal.”

The scientist and his team are planning to take more samples of the area and try to discover more about the water.

Speaking about the discovery, Director Demian Saffer added: “This is something that we’ve hypothesized from lab experiments, and is predicted by some computer simulations, but there are very few clear field experiments to test this at the scale of a tectonic plate.”

Clearly, there’s motion in the ocean in New Zealand!