This is known as groundwater.
Most of the earths surface is covered with water. There is land under that water though, below the surface.
it is water cycle
70% or 80% of water covers the earths surface
it will over flood the earths surface with melt water of the ice berg and detroy land under sea level
3/4 of the earth's surface is water.
69%
about 30%
the sun
Water.
Ground water.
the water cycle
To the best of my knowledge, the water under the surface was formed when the oceans were formed, or thereafter. In simple terms, cracks in the ground allows water to leak below ground into large open voids.