摘要 |
<p>The two-way water-layer travel time, tau , is derived from dual-mode seismic sensor data by cross-correlating the Fourier transforms of the sum and difference of the velocity and pressure signatures. The Z-transform of tau evaluates one of the two Backus variables, Zw. The second variable is Rb, the water bottom reflectivity coefficient. The frequency-domain transforms of the above summed and differenced signatures are each multiplied by the Backus operator (1+RbZw)<2> after initializing Rb and the products are iteratively cross-correlated until the correlation function converges to a minimum. Rb is perturbed after each iteration. The value of Rb upon convergence is the local water bottom reflectivity coefficient. <IMAGE></p> |