Review of Geoacoustic Inversion in Underwater Acoustics

This paper reviews the progress in geoacoustic inversion over the past several decades. The review is separated into two parts. The first part reviews developments in model-based inversion methods that have led to present day usage of Bayesian inference. Theoretical foundations for the inversion methods are outlined, and limitations of model-based approaches are discussed. Examples are briefly described of applications of model-based inversion with different types of experimental data. The second part reviews recent developments in model-free inversion methods, focusing on discussion of distortion of estimated geoacoustic model parameters caused by model mismatch. It is shown that distortions in estimated model parameters lead to errors in interpreting characteristics of dispersion in the ocean waveguide, in particular the frequency dependence of sound attenuation in marine sediment. This review concludes with perspectives on new directions in research that promise improvement in inversion performance.