A professor, named Stevenson Jacobsen, at the Northwestern University and a seismologist, named Brandon Schmandt, from the University of Mexico, found proof that our oceans could've emerged from a reserve that is 400 miles below Earth's crust. Brandon studied the seismic waves of 500 earthquakes. His team noticed that the speed of waves slowed down when it passed through ringwoodite. Jacobsen's team found the same thing when they did their technique except that it was a mineral in their lab. When the waves went through the ringwoodite, wtaer squeezed out of it.
The water gets stored in the transition zone because the ringwoodite has a crystal structure that is like a sponge so it stores the water. Since the pressure is mixed with high temperatures, the water splits into hydoxyl radical. This finding helps scientists to figure out that our oceans are probably the result of geological activity pushing out some of the large reserves that are underneath, it also means that our oceans have been the same size for millions of years.