The ratio of the fractional transverse contraction to the fractional longitudinal extension when a long isotropic rod is stretched.
Equivalently: the negative of the ratio of axial strain to radial strain in a long cylinder (with stress-free sides) of an isotropic medium.
Named for Siméon Poisson, French physicist. Specifying Poisson’s ratio is equivalent to specifying the ratio of VS/VP, where VS, and VP are S- and P-wave velocities. Values ordinarily range from 0.5 (no shear strength, e.g., fluid) to 0 (but theoretically from 0.5 to –1.0; see Debski and Tarantola, 1995).
- Debski, W. and Tarantola, A., 1995, Information of elastic parameters obtained from the amplitudes of elastic waves: Geophysics, 60, 1426–1436.