Removal of Multipath Effects in the Estimation of Rayleigh Wave Spectra

摘要

The effects of multipathing on the Rayleigh spectrum mask depth-dependent spectral zeroes and cause significant errors in magnitude determinations. A new technique, called phase equilization filtering, is introduced for the purpose of eliminating multipath effects. The technique is demonstrated to be effective on synthetic signals in which the undisturbed spectrum is known. In a typical case, an 18-dB spectral hole at a period of 20 seconds, caused by multipathed energy arriving only 30 seconds later than the primary arrival, was essentially eliminated. The usefulness of the technique is also demonstrated by application to teleseismic Rayleigh waves. (Author)