The ability to calculate traveltimes and amplitudes of seismic waves is useful for many reflection seismology applications such as migration and tomography. Traditionally, ray tracing (C⁁erveny et al., 1977; Julian, 1977), paraxial methods (Claerbout, 1971), or full‐wave methods (Alterman and Karal, 1968) are used for such calculations. These methods have in common considerable computational expense. Recently, Vidale (1988, 1990a) presented two‐dimensional and three‐dimensional methods to efficiently compute traveltimes of the first arrivals to every point in a regularly spaced grid of points, given an arbitrary velocity field sampled at these points. The computational cost of finding each traveltime is roughly one square root operation.
Lightning Response of Multi-Port Grids Buried in Dispersive Soils: An Approximation versus Full-wave Methods and Experiment