A seismic pulse is influenced by the various media through which it has travelled. The crust is known to have a considerable influence. With the use of the Thomson-Haskell matrix formulation, the crustal effect can be easily calculated. Because a time window is imposed on the signal, it is necessary to take into account this truncation in calculating the theoretical crustal effects. A method to obtain truncated crustal transfer functions is presented.
It is suggested that the frequency analysis of short-period P waves can yield detailed information on the crustal structure at a given station when selected truncated transfer functions are used as crustal inverse filters. The basis for deciding upon a particular model is the optimum match between one of a series of spectra corrected for a series of crustal models and the approximated spectrum of the incident pulse obtained through the averaging of many well grouped spectra.