Body Wave Amplitude Calculations--II

A modification of asymptotic ray theory that replaces the ‘energy propagation in tubes’ determination of amplitude by a ‘disk superposition model of the wavefront’ leads to a simple construction technique for synthetic seismograms. The disk-ray theory (DRT) method generates arrivals based solely on the distance function Δ(p). The DRT computed arrivals compare very well with wave theory computations for caustics, reflections and refractions. The approximation of head-waves is adequate only at high frequencies. No approximation at all is made for the effects of waveguides, tunnelling or diffraction at spherical interfaces.