Dictionary:Gassmann equation

{{#category_index:G|Gassmann equation}} (gasz' man) Seismic P-wave velocity through a dense packing of uniform spheres is proportional to

$\left[{\frac {E^{2}z}{\left(1-\sigma ^{2}\right)^{2}}}\right]^{1/6}$,

where E=Young's modulus, z=pressure (or depth where proportional to pressure), $\sigma$=Poisson's ratio. See Gassmann (1951). Named for Fritz Gassmann, Swiss geophysicist.