ASA 124th Meeting New Orleans 1992 October

4aUW6. Two-dimensional cross correlation of reverberation data.

L. Canales

J. Harris

Stanford Univ., Dept. of Geophys., Stanford, CA 94305

E. J. Yoerger

J. W. Caruthers

NRI, Stennis Space Center, MS 39529

A technique of time stretching time-series data is applied to reverberation time sequences beamformed from a multielement horizontal receiving array. For different, but nearby, array locations, beams that are scattered off a common area should be highly correlated. The correction method applied here maps each beamformed time series such that common scatterers coincide in position on a 2-D grid. The method uses an average pilot signal and 2-D cross correlations to stretch the time series in a way similar to static corrections in surface seismic processing. This process requires multiple iterations and the average pilot signal is recalculated between iterations. This method was applied to the aforementioned data from five different array locations using an average pilot signal. The results showed a high degree of correlation among the time series. The results are compared with available bathymetry to determine if scattering events can be matched with bottom features. [Work supported by ONR.]