Extrapolation of geoacoustic properties using seismic reflection data: A shallow water example

Abstract

In areas of the world that are bottom limited, sonar performance models require accurate seabed geoacoustic properties. Geoacoustic properties, e.g., sound speed, density, and attenuation as a function of depth, frequency and geographic position, are expensive to acquire over large areas. Most geoacoustic techniques, including direct sampling (e.g., cores, probes) or acoustic inversion methods (e.g., matched field methods) spatially sample either in 1‐D or 2‐D. Conducting these measurements in a dense grid over large areas is not feasible and as a consequence seabed database developers rely on seismic reflection data coupled with geologic models to spatially interpolate and extrapolate the geoacoustic properties. Seismic reflection data is attractive for this purpose because it has much greater geographic coverage and contains information on underlying geologic processes that ultimately control the geoacoustic properties. The inherent strengths and weaknesses of seismic data for geoacoustic extrapolation are explored using seismic reflection transects in the Straits of Sicily together with ground‐truth geoacoustic properties and their uncertainties (from wide‐angle reflection measurements) at each end of the transect. The uncertainties of the extrapolated geoacoustic properties are determined with and without the ground‐truth data. [Work supported by the Office of Naval Research OA321 and the NATO Undersea Research Centre.]