Abstract：The formulas for separating out compressional wave or shear wave in surface seismic records are derived from elastic wave equation.According to the formula,revising the vertical component with the use of horizontal component of elastic wave field received on the surface can enhance compressional wave but remove shear wave in the vertical component,thus separating out compressional wave similarly,shear wave may be separated out by revising the horizontal compovent with the use of the vertical component of the elastic field.The equations of separating out compressional wave or shear wave are all solved by using difference method.The solving only involves both seismic velocity at the surface and the component contents of the elastic wave field which is received by geophones on the surface,and it is independent of source and medium.This method also applies to the case where surface velocity varies laterally.
