21. Bending waves are more complicated than compressional or shear waves and depend on material properties as well as geometric properties. 22. In the high frequency limit, the phase and group velocities of all these modes converge to the shear wave velocity. 23. Rayleigh waves have a speed slightly less than shear waves by a factor dependent on the elastic constants of the material. 24. Shear waves may also be generated by the use of elastically anisotropic solids cut at oblique angles to the crystal axes.25. It has been shown theoretically that in a certain low-frequency range, polymeric gels should propagate shear waves with relatively low damping. 26. The speed of shear waves , which can occur only in solids, is determined simply by the solid material's shear modulus and density. 27. The pattern of increasing shear wave splitting time-delays is typical of the increase now seen before many earthquakes in Iceland and elsewhere. 28. Their shear wave velocity reduction is on the order of-10 to-30 % and the compressional wave velocity reduction tends to be weaker. 29. In addition to stress waves, Bellamy and Zajtchuck describe shear waves as a possible mechanism of indirect injuries in the WDMET data. 30. These different waves ( compression waves and the different polarizations of shear waves ) may have different speeds at the same frequency.
