The stratum or strata below the earth's surface.
- ‘Ground penetrating radar provides an image of the subsurface showing the internal structure of dunes.’
- ‘Also, in some areas (rift valleys) they receive hydrothermal magmatic waters from the subsurface.’
- ‘It seeps through the earth to a subsurface water table, which flows horizontally to a stream bank.’
- ‘It has been estimated that half the biomass of life on the Earth resides in the subsurface doing things other than photosynthesis.’
- ‘Strong, continuous stratal reflections characterize the shallow subsurface on the upper and middle shelf.’