Norman S. Neidell, 1987. "G. Non-Normal Incidence Reflections and the Determination of Lithology - Use of Shear Waves and Amplitude with Offset", Geophysical Determination of Lithology: Using Shear Waves and Amplitudes with Offsets, Norman S. Neidell
Download citation file:
In correlating seismic data with subsurface information, It often proves convenient to use normal incidence reflections as the analytic formalism. Recall that the one-dimensional approaches as represented by seismogram synthesis assume a flat-layered subsurface and so the vertical travel paths employed are also taken to be normal incidence. Where two and even three-dimensional simulations are employed, normal incidence rays are important because they approximate the CDP stacked traces guite well and under a wide variety of circumstances. Indeed, the usual field technigues for acguiring seismic data are geared toward satisfying this approximation. Nence it is worthwhile to review the acquisition criteria in order to note how relaxation of certain of them might provide additional information about the subsurface.
A Figure and discussion from the familiar text by Dobrin (1) points out that a compressional wave incident on an acoustic impedance contrast (or boundary) generates both compressional and shear reflection and transmission components. Intuitively, the reason that such complex behavior occurs is analogous to the logic which suggests that fractures in rocks must stand vertically rather than horizontally.
Figures & Tables
Geophysical Determination of Lithology: Using Shear Waves and Amplitudes with Offsets
In correlating seismic data with subsurface information, it often proves convenient to use normal incidence reflections as the analytic formalism. This publication covers shear waves, in both land and marine applications, as well as considerations, studies, and modeling techniques dealing with amplitude variation with offset.