Elasticity is the property which have some solids which recovers their initial form after being deformed (in some limit) by the application of a force.
The couple modulus of compressibility , K_T, modulus of rigidity, G_T, is classically used in logging to describe the elastic behavior of the rocks. Other couples of variables can describe elasticity as the Young modulus and the coefficient of Poisson (E, ) or the two coefficients of Lamé (,). the table hereafter shows the correspondences between these various modules.

Table of constant