HYPERFINE BEAMSTEERING USING A SIGNAL CROSSCORRELATION TECHNIQUE
Seismic data laboratory rept.
TELEDYNE INDUSTRIES INC ALEXANDRIA VA EARTH SCIENCES DIV
Pagination or Media Count:
A method is developed to eliminate automatically the loss in signal amplitude of LASA phased sums with travel-time anomaly corrections due to small mis-alignments in the signal arrivals. This method is a hyper-fine or vernier adjustment of the trace alignments, making use of a least-squares estimate of the misalignments made from the time lags of all possible crosscorrelations between the signals. A mathematical description of the procedure and its errors is given. Three events with different signal-to-noise ratios recorded by 11 LASA subarrays were chosen as examples of the method. The results show improvements ranging from 0.0 to 0.5 db in the phased sum of the subarray sums. The results seem to depend on the signal-to-noise ratio of the event, the method performing best when that ratio is high.