Incompressibility

Definition

Incompressibility (K) is an elastic property of a material which describes the measure of which the material resists change in volume (compression) when subjected to uniform pressure. it is also known as Bulk Modulus .

Incompressibilty is an elastic constant mathematically defined as the ratio of the applied pressure(stress) to the volume strain caused by the pressure. This is illustrated below:

$K={\frac {P}{\Delta V/V}}$

     where P denotes pressure or stress
     V denotes volume
     The delta V (ΔV) denotes change in volume.

Application in Geophysics

The incompressibilty of Earth materials (Rocks and Fluids) greatly determine their acoustic velocities (V_P and V_S). The elastic constant can expressed in terms of acoustic velocities as shown below:

$K=\rho \left(V_{\mathrm {P} }^{2}-{\frac {4}{3}}V_{\mathrm {S} }^{2}\right)$

Related Topics

• Bulk modulus
• Elastic modulus
• Shear modulus

External links

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