Dynamic moduli

The denomination of the “dynamic” term, refers to all the elastic properties that have been obtain from geophysical logs. The dynamic moduli is usually larger than the corresponding static moduli. This difference is larger for weak rocks and is smaller with increasing confinement.

The dynamic shear modulus, G_dyn, shown below, is also known as the modulus of rigidity, a measure of the sample’s resistance to shear deformation.

The dynamic P-wave modulus, M_dyn, is

The dynamic bulk modulus, K_dyn, shown below, is a measurement of the sample’s resistance to hydrostatic compression. The inverse of K is known as the compressibility.

The dynamic Young’s modulus, E_dyn, is