Researchers have long suspected that there is a massive water reservoir deep within the Earth. Now, that theory has been confirmed.

Hidden ocean found deep within the Earth

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Cheryl Santa Maria

Digital Reporter

Thursday, June 12, 2014, 6:24 PM - Back in March researchers at the University of Alberta made headlines when they confirmed a 50-year old theory that the centre of the Earth contains a mineral named ringwoodite.

When U of A researchers discovered the first naturally-occurring piece of ringwoodite embedded in a diamond from deep within the Earth, it marked the first time anybody had ever seen the elusive material.

Approximately 2.5 % of ringwoodite's composition is water, leading scientists to believe that a hidden reservoir exists deep within the Earth.

Now -- that theory has proven correct.

A study published Thursday has confirmed the existence of a massive water reservoir containing three times the volume of the Earth's oceans some 700 kilometres underground.

The water, according to researchers at Northwestern University in Illinois, is concealed inside the ringwoodite, which lies inside the Earth's mantle -- i.e., the layer of rock between our planet's surface and core.

The team used 2,000 seismometers to study seismic waves spurred by hundreds of earthquakes. Upon analyzing the speed of the waves at different depths, the team was able to figure out what types of rocks were moving around.

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According to NewScientist, the water layer revealed itself because the seismic waves slowed down at the mantle because it "takes them longer to get through soggy rock than dry rock."

The findings could shed some light on where our oceans came from.

While some experts believe our water accumulated as comets struck the planet, the new discovery suggests that the ocean water may have migrated to the surface from the Earth's mantle.

"We should be grateful for this deep reservoir," lead author Steven D. Jacobson was quoted as saying.

"If it wasn't there, it would be on the surface of the Earth, and mountain tops would be the only land poking out."

The complete paper can be found in the journal Science.