Phase change of PP and pP on reflection at a free surface*

Abstract

The question of phase change on reflection at a free surface is investigated for all values of Poisson's ratio σ. It is shown once again that for σ > 0.2631 there is always a phase change on reflection. For σ < 0.2631 there are certain angles of incidence for which there is no phase change on reflection. These angles are determined for values of σ between 0.26 and 0.00. The results are also expressed, for various focal depths, in terms of the epicentral distances for PP and for pP between which there has been no phase change on reflection.