Geothermal Gradient

The geothermal gradient is the rate at which temperature increases with depth into the Earth's interior, driven by the flow of heat from the much hotter mantle into the crust above it. Away from tectonic plate boundaries, temperature in the continental crust typically rises by about 25 to 30 degrees Celsius per kilometer of depth near the surface. In some settings the near surface gradient can instead run in reverse, a condition known as an inverse or negative geothermal gradient, though the shallow effects of weather and climate on ground temperature reach down only about 10 to 20 meters.