Gaussian beams, approximate solutions of elastodynamic equation concentrated close to rays of high-frequency seismic body waves, propagating in inhomogeneous anisotropic layered structures, are studied. They have Gaussian amplitude distribution along any straight line profile intersecting the ray.
At any point of the ray, the Gaussian distribution of amplitudes is controlled by the 2×2 complex-valued symmetric matrix M(y) of the second derivatives of the travel-time field with respect to wavefront orthonormal coordinates y1, y2, local Cartesian coordinates in a plane tangential to the wavefront with its origin at the central ray. In: Seismic Waves in Complex 3-D Structures, Report 20, pp. 127-168, Dep.
Geophys., Charles Univ., Prague, 2010.