Reverberation imaging.

Abstract

Reverberation imaging is a technique that creates an image of surface and bottom scatterers using low-frequency reverberation data. Reverberation from explosive charges of moderate size are known to last tens of minutes covering a basin-wide ocean. The backscattered signals (reverberations) carry information on the nature and locations of boundary features, thus affording wide-area knowledge from a single measurement location. Because of the multipath propagations, conventional processing of backscattered (reverberation) data cannot separate long-range returns arriving simultaneously from the surface and the bottom, except where there is a dominant feature such as a seamount. Matched field/mode processing could in principle be used to localize the surface and bottom scatterers separately except that these methods assume pointlike sources whereas in reality the scatterers are extended objects. This paper addresses modified matched field/mode processing to create images of surface and bottom scatterers separately.