A SIMPLIFICATION OF THE ZOEPPRITZ EQUATIONS

The compressional wave reflection coefficient R( theta ) given by the Zoeppritz equations is simplified. The result is arranged into three terms which contribute to three distinct features of the R( theta ) curve: (1) the normal-incidence magnitude, (2) the behavior at intermediate angles of about 30 degrees, and (3) the approach to critical angle. Thus the author approximately diagonalize the multivariate relationship between elastic properties and curve features. The coefficient for intermediate angles has two terms: one term is proportional to TRIAN OP sigma , the contrast in Poisson's ratio; and the other term is TRIAN OP A//0, which describes the bland decrease of R( theta ) in the absence of contract in Poisson's ratio. When angles approaching critical are not included, R( theta ) may be adequately approximated by a parabola.