A note on the propagation of a sound pulse in a two‐layer liquid medium

The contribution from the branch line integral in Pekeris' formulation of the propagation of explosive sound in a two-layer liquid medium is investigated. It is shown that there is no net contribution to the solution in terms of pressure amplitude measured in the upper layer, which decays less rapidly than r−2. The horizontal range, designated by r, is large compared with the depth of the layer. This result is applicable to early arrival pressure signals and is in agreement with recently published model experiments.