Adaptive Multiple Subtraction with Non-Stationary Helical Shaping Filters

P 167 ADAPTIVE MULTIPLE SUBTRACTION WITH NON-STATIONARY HELICAL SHAPING FILTERS 1 SUMMARY JAMES RICKETT ANTOINE GUITTON AND DOUGLAS GRATWICK Department of Geophysics Stanford University Stanford CA 94305 USA We suppress surface-related multiples with a smart adaptive least-squares subtraction scheme in the time-space domain after modelling multiples with a very fast but approximate modelling algorithm. The subtraction scheme is based on using a linear solver to estimate a damped non-stationary shaping filter. Convergence is improved by the preconditioning with a space domain helical roughening filter. Dragoset and Jeričević (1998) describe a two-step multiple elimination process: prediction followed by subtraction with an