A preliminary study of the geoacoustic parameters of gassy sediment in St. Margaret's Bay, Nova Scotia

Marie-Noël R. Matthews, Francine Desharnais, David J. Thomson, Gordon Ebbeson, Garry J. Heard

Abstract


The geoacoustic parameters of gassy sediment of St. Margert's Bay, Nova Scotia, were investigated. The geoacoustic parameters of gassy sediment such as sound speed (cs), attenuation (αs), and density were analyzed at frequencies below 500 Hz by comparing the measured and modeled transmission loss (TL) as function of range. A low-frequency underwater source was towed along a straight transit and two set of TL was measured for each hydrophone of the vertical array and simulated signal propagating over seabed models using a parabolic equations. The acoustic propagation of simulated signals were modeled for two different seabed models to calculate the TL vs range. These curves are then compared to measure TL from real underwater sources. It was observed that geoacoustic parameters of gassy layers showed correlation between real and modeled TL. Result shows that geoacoustic model for St. Margert's Bay produce TL match at frequencies below 500 Hz.

Keywords


Acoustics; Correlation methods; Geophysics; Mathematical models; Parameter estimation; Gassy sediments; Geoacoustic parameters; Simulated signals

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