Poisson's ratio and the porosity of surface soils and shallow sediments, determined from seismic compressional and shear wave velocities

Propagation of compressional (P) and shear (S) waves through soils, sediments and rocks is governed by various factors, including:

Poisson's ratio σ is a measure of the transverse strain or contraction to longitudinal strain or extension resulting from a change in normal stress under compression or dilatation. A change in the wave propagation from one lithology to another or from an unsaturated to a saturated medium leads to variations in the value of σ from 0 (indicating a considerable change in volume) to 0·5 (indicating no volumetric change, corresponding to fluids). Also, σ can have negative values, and these indicate...