Acoustic signals scattered from the sea floor at nearly vertical incidence contain information about the physical properties of the sea floor. Signals may be decomposed into spatially coherent and spatially incoherent components the relative magnitudes of which are primarily a function of small scale bottom roughness. Experimental interping coherence functions derived on the basis of a linear system scattering model are shown to characterize contrasting sediment lithologies. The use of interping coherence as a sediment remote classification criterion and hence as a tracer of gross geotechnical properties is explored.

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A multi-device high density survey of the seafloor was conducted in the outer Placentia Bay area of Newfoundland using the Bedford Institute of Oceanography research ship CSS Hudson. The acoustic records obtained from various systems, the seafloor soil samples collected by a piston corer and a grab sampler, and the in-situ data from a free-fall penetrometer were all subsequently analyzed. The correlation between the results of these different analyses is examined in this paper.

Shallow marine sediments can be remotely classified by the spatial correlation properties of their seismic reflection signatures provided one uses a highly repetitive broadband acoustic source. A classification scheme defined by three spatial coherence parameters is shown capable of automatically differentiating between several formations of unconsolidated sediments in a limited area of offshore Newfoundland. The consistency and generality of the technique are explored and comparisons with standard echograrn interpretation are made.Les formations marines skdimentaires h faible profondeur peuvent &tre classifikes B distance par corrklation dans l'espace de propriCtCs Cmanant des profils de sismique rkflexion pourvu que l'on utilise une source sonore h large bande fidklement rkpktitive. Une classification mktrique dkfinie par trois parametres de cohCrence spatiale permet automatiquement de distinguer entre elles plusieurs formations de skdiments nonconsolidCs dans une rCgion d'ttendue IimitCe sur I'offshore de Terre-Neuve. L'uniformitC des rCsultats et l'application gCnkraliske de la technique sont Ctudikes et des comparisons sont faites avec llinterprCtation d'kchogrammes types.[Traduit par le journal]Can.

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