A huge amount of water is sinking through Earth's tectonic fault line: Study- Technology News, Firstpost

Indo-Asian News Service
Nov 16, 2018 10:10 AM IST

The Earth is more likely to be affected by seismic studies, with major implications for the global water cycle.

Mariana Trench – deepest ocean trench in the world.

The trench is where the western pacific ocean plate slides beneath the Mariana plate and sinks deep into the earth's mantle as the plates slowly converge.

"People knew that subduction zones could bring water, but they did not know how much water," said lead author Chen Cai, from the Washington University in St. Louis.

"Candide Major, a program director in the National Science Foundation 's Division of Ocean Sciences, said:" This research shows that subduction zones have become more important.

For the study, published in the journal Nature, the team listened to more than one year's worth of Earth's rumblings – from ambient to actual earthquakes – using a network of 19 passive, ocean-bottom seismographs across the Mariana Trench, along with seven island-based seismographs.

They found that ocean water at the bottom of the earth's crust and upper mantle. Then it gets trapped.

Under certain temperature and pressure conditions, chemical reactions force the water into a non-liquid form as hydrous minerals – wet rocks – the water in the rock in the geologic plate.

Then, the plate continues to crawl deeper into the Earth's mantle, bringing the water along with it.

The seismic images show that the area of ​​hydrated rock at the Mariana Trench extends almost 20 miles or 32.2 km beneath the seafloor, the study showed.

For the Mariana Trench region alone, four times more water subducts than previously calculated. These features can be extrapolated to predict the conditions under other ocean trenches worldwide.

Scientists believe that most of the water that goes down the trench comes from the Earth into the atmosphere as water vapor when volcanoes erupt hundreds of miles away.

But with the revised estimates of water, the amount of water going into the earth, the researchers noted.