Geological research has determined that there is an area of the Earth's interior with water under great pressure. This research used geodynamic modeling and high-temperature melting experiments, determining that the transition zone is 440 to 660 kilometers deep, a region with water under high pressure.
The dehydration of internal regions through melting and an accumulation of water in a specific area of the globe is idealized. In a way, this idea of dehydration is a more accepted theory, the fact is that this region is determined as a region with water.
It may have existed during the formation of the planet, but in this case it would go against the standard accepted model of planet formation. In fact, the basic idea is that the Earth was a hot planet and that molten rock dominated the environment. Over time it cooled down, but in this case a problem is posed: where did the water come from? Because at high temperatures, water would leave the planet and escape through the atmosphere. Thus, we would have a planet without water.
In this way, they created the idea that a meteor, or several meteors, brought water to the planet, an idea that is really very difficult to accept in a probabilistic way. But if we have water trapped almost 700 kilometers away, then the idea of meteors is extremely compromised. Because such meteors would have to bring water to great depths, and remain trapped there.
Normally, when the probabilistic system tends to zero, that is, it is extremely improbable, the most rational thing would be to accept a directed mechanism, that is, something planned. But normally science does not accept the idea of planned systems, and opts for everything by means of random mechanisms, even if such are totally impossible.