A surprising amount of water from the planet slips deep into the surface of the earth within certain tectonic boundaries, a new comprehensive seismic study of the Mariana Canal trenches revealed, reports Phys.org.
The first study of its kind, which took place along the deepest channel in the world, found that the amount of water that passes through the "cracks" along the regions of change – places where tectonic plates drop deep into the Earth – can be as much as four times what previous estimates suggested. And the water disappears even deeper into the planet's envelope, 20 miles below the seafloor.
"People knew that the cutting areas could drop water, but they did not know how much water," said Tsun Ai of the University of Washington, the first author on the study.
"This study shows that the switching areas transfer much more water into the deep interior of the Earth – many kilometers below the surface – than previously thought," said Candace Meigher, program manager at the National Science Foundation's Division of Marine Sciences, The research.
The cutting regions, which cause most of the deepest trenches of the Earth, can draw water into the Earth because of the enormous pressure and temperature they create. Rocks along these borders can act like sponges, absorb the water and drag them down. It was not until now that scientists knew exactly how much water has been pumped down, and the numbers are so significant that it is not clear where the water is.
Where did all this water go?
The good news is that a large part of the water will likely back up bubbles at some point. For example, volcanoes flow water vapor back into the atmosphere as part of the water cycle. The only problem is, measurements of water vapor released by volcanoes fall in the estimates from this study of the amount of water lost through subduction. In other words, it appears that the amount of water entering the soil far exceeds the amount of water that goes out.
So at this point, where water goes a bit of mystery. It is not lost – Earth's Earth levels have not sunk dramatically throughout the planet's history – but more research will be needed to understand how the water cycle sustains itself.
"Estimates of water coming back through volcanic arc are probably very uncertain," said Doug Vince, research consultant on the study. "This study will probably be re-evaluated."
One possible explanation is that not all crop regions are created equal. Perhaps the conditions along the Mariana Canal are more extreme than in other places around the planet, where less water is lost. This is a hypothesis for another study, however.
"Does the amount of water vary significantly from one sub-region to another based on the type of faults you have when your plate is bent?" Asked Vince. "There were such proposals in Alaska and Central America, but no one looked at the deeper structure, as we can do in the Mariana Canal."
An enormous amount of water sinks through the tectonic lines of the planet
An excessive amount of water from the planet slips deep into the earth's interior in some tectonic boundaries, a new study found. But where is it going?