Propagation and attenuation of seismic body waves in initially stressed dissipative medium

The paper discussed the effect of initial stresses on the propagation and attenuation of seismic body waves in a dissipative medium. The study reveals that the presence of initial stresses has strong effect in the propagation and attenuation of seismic waves. The velocity of waves depends on the direction of propagation and pure longitudinal and transverse waves are available only in the direction of initial stress and perpendicular to it. In other directions, a longitudinal wave is accompanied by some rotation and a transverse wave by some dilatation. The study also shows that the presence of compressive initial stress increases the velocity of longitudinal wave but diminishes that of trahsverse wave. It is also observed taht the loss of longitudinal wave due to dissipation is maximum in the initially stress-free case and decreases as the initial stress increases. In the case of SV wave, the presence of initil stresses decreases the loss factor upto the point when the direction of propagation makes an angle of 55° with the direction of initial stress, and then increases.