Bulk Modulus 4
Bulk Modulus 4 : The modulus of volume elasticity which relates a change in volume to a change in hydrostatic pressure. It is the reciprocal of compressibility. See Birch (1966) for an introduction and a Compilation of values, section 2.2 in Chapter 2 of this Manual and Eq. (1.6) in Ben-Zion (2003)