Summary. A Debye model using two cut-off frequencies corresponding to compressional and shear velocities is used to calculate mineral entropies. This model permits entropy and heat capacity in the Earth to be calculated from seismic profiles, and iteration yields temperature profiles along an isentrope. With an adiabatic temperature profile it is possible to obtain Grüneisen's parameter and thermal expansion as a function of depth. Only in the lower mantle is the calculated Grüneisen's parameter along an isentrope approximately proportional to volume.