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Rate of Geothermal Temperature  change along True Vertical Direction with no account of effects of the seasonal/daily temperature variations ( which are only noticeable above Neutral Temperature Layer ):

Ratio of ture vertical compnent of the Earth heat flux to the subsurface heat conbductivity:

G_T({\bf r}) = \frac{j_z({\bf r})}{\lambda_e({\bf r})}


Fig. 1. Schematic view of the Earth's Geothermal Temperature Gradient.


The most common value of Geothermal Temperature Gradient away from tectonic plate boundaries  : GT = 0.025 ÷ 0.030 °C/m. 

See Also


Geology / Geothermal Temperature Field

Geothermal Temperature Gradient (GradT) ] [  Geothermal Temperature Profile (TG) ]