Examples of the Use of the Fourier Transform in Applied Seismics

Abstract

Spectral analysis is useful in geophysical studies for solving problems of data acquisition, data processing, and interpretation in the frequency and wavenumber domains. In exploration seismics, the tools of spectrum analysis can be used, for example, for the following purposes:

• data acquisition:

  • specification of instrument parameters;

  • optimization of source and receiver configuration;

• data processing:

  • improvement of resolution by spectrum whitening, i.e., adjustment of the amplitudes of all frequency components within a certain band-pass to the same level;

  • improvement of the signal-to-noise ratio, for example, by suppressing random or coherent noise by frequency or velocity filtering, respectively;

  • removal of undesired filtering effects, for instance, of near-surface layers or the measuring equipment. This is necessary, for example, for the determination of the true ground motion, a prerequisite for the study of the source process of an earthquake.