Accession Number : AD0787689
Title : Cross-Correlation Techniques for the Determination of the Complex Shear Modulus of the Ocean Bottom.
Descriptive Note : Final rept.,
Corporate Author : SCIENTIFIC RESEARCH ASSOCIATES INC ROCKVILLE MD
Personal Author(s) : Hudimac,Albert A.
Report Date : 28 AUG 1974
Pagination or Media Count : 21
Abstract : Cross-correlation methods were used to determine the time delay and attenuation of a cylindrical shear wave projected by a pulse-modulated source. To overcome the difficulty because of the distortion of the received signal due to strongly frequency dependent absorption and the need to operate in the near-field, the cross-correlation between the predicted signal and the received signal is expressed. The predicted signal is obtained by the analysis of the propagation of shear wave with the known displacement on the surface of the projector as the boundary condition; the result is given as a function of the unknown real and imaginary parts of the shear modulus (which are assumed to be frequency independent). An iterative procedure is given for the determination of the unknowns. (Author)
Descriptors : *Ocean bottom, *Shear properties, Signal processing, Fourier transformation, Complex variables, Numerical integration
Subject Categories : Physical and Dynamic Oceanography
Distribution Statement : APPROVED FOR PUBLIC RELEASE