The Earth sucks its own water

The researchers discovered that the Earth sucks up huge quantities of water. When tectonic plates collide under the ocean, they drag the water into the deep Earth and the process absorbs about three times more water than previously predicted.

Earth's tectonic plates slide under another in a subduction zone. They press water from the surface of the Earth and feed volcanoes, which are then released into the oceans by volcanic eruptions. These inputs and outputs generate a global cycle of deep waters. But until now, researchers were unaware of the amount of water drawn into the Earth's interior.

"This research shows that subduction zones move much more water than previously thought in the depths of the Earth's interior," said Candace Major of the Division of Earth Sciences. Sea of ​​the National Science Foundation. "The results highlight the important role of subduction zones in the Earth's Water Cycle."

To conduct this study, the researchers selected the deepest oceanic trench in the world and listened to the natural seismic rumblings of the earthquake with the help of a network of instruments deployed across the trench of the Marianas. The first seismic survey of its kind provides a more detailed portrait of the plate of the Pacific Ocean folded in the trench. When the plates collide and the descending plates creep deeper and deeper into the Earth's mantle, they drag the water.

"Previous conventions were based on active source studies, which can only show 3 to 4 miles in the incoming plate," said Chen Cai of the University of Washington. "They could not be very precise about its thickness, nor about its hydration.Our study tried to limit it.If the water can penetrate deeper into the plate, it can stay there and be brought back to deeper depths. deep. "

The latest seismic images show an area of ​​the Marianas Trench that stretches for nearly 20 miles under the seabed and contains a considerable amount of water.

"If other old slabs, subjected to a cold subduction, contain a layer of similar thickness of hydrated mantle, estimates of the overall flow of water in the mantle at depths greater than 60 miles shall to be multiplied by three, "said researcher Doug Wiens.

"Does the amount of water vary considerably from one subduction zone to another, depending on the type of defect you have when the plate bends?" Suggestions were made in Alaska and Central America. But no one has yet examined the deepest structure, as we have been able to do in the Mariana Trench. "