Estimation of seafloor geoacoustic parameters from cross correlation of measured and simulated broadband signals

Abstract

The ratio R of the compressional (P) wave velocity to water sound speed, and g, the gradient of P wave velocity, have been measured for an abyssal plains environment by maximizing the similarity between measured and simulated low‐frequency broadband acoustic signals from a single shot (explosive source) at long range. Simulated time series were produced by a computational model that predicts low‐frequency bottom interacting waveforms that agree well with small grazing angle acoustic data from this environment [D. P. Knobles and P. J. Vidmar, J. Acoust. Soc. Am. 79, 1760–1766 (1986)]. Our measure similarity is Cmax, the maximum of the absolute value of the cross‐correlation function of two time series, and Cmax has a strong dependence on R, g, and the experimental geometry; it has a weak dependence on the sediment density and P wave attenuation. Estimates of R and g agree with reported values. [Work supported by the NORDA Bottom Interaction Program.]