rotational wave

5.11  shear wave; rotational wave. Wave in an elastic medium which causes an element of the medium to change its shape without a change in volume.

Annotation 1          Mathematically, a shear wave is one for which the velocity field has zero divergence.

Annotation 2          A shear wave in an isotropic medium is a transverse wave.

Annotation 3          When shear waves combine to produce standing waves, linear displacements may result.