STUDIES OF THE EFFECT OF DEPTH OF FOCUS ON SEISMIC PULSES
Final rept., 1 Jan 19-31 Oct 1966
PENNSYLVANIA STATE UNIV STATE COLLEGE DEPT OF GEOLOGY AND GEOPHYSICS
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This report summarizes the conclusions reached in thirty other reports issued in connection with this contract, and lists the individual reports which detail how each of the objectives of the contract was reached. The principal method used in an attempt to measure depth-of-focus of shallow events is the Watson-Merdler inverse-filtering technique. It is shown that a simplified version of this method which neglects noise also finds ghosts in a seismogram, as does cross-correlation. The three methods frequently but not always find the same ghosts. Two important factors which make it difficult for all three methods to find ghosts are that short-period seismometers do not record the main part of the energy in most seismic pulses and the ghosts commonly differ greatly from their primaries in waveform and frequency spectrum.