Abstract：The reflecting point of converted wave is not beneath the center of the line between source point and corresponding receiving point, and its deviation to the center depends on both velocity Vs of converted shear wave and reflecting point depth h. Reflection times of converted waves which are reflected at a subsurface point and received on surface do not follow hyperbolic law of reflected compressional wave, so that velocity analysis method for compressional wave does not apply to converted waves. Stack velocity analysis method for converted wave, which considers depth variation in vertical direction and does velocity-variable trace gathering in lateral direction, avoids troubles resulting from both the asymmetry of converted-wave line-ups and the non-hyperbolic characteristic of reflection time values to achieve accurate velocity analysis of converted wave. This method has been used to process converted-wave data of 92LYS501 seismic line, bringing desirable result.
