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dc.contributor.authorFrisk, George V.  Concept link
dc.contributor.authorDoutt, James A.  Concept link
dc.contributor.authorHays, Earl E.  Concept link
dc.date.accessioned2018-04-18T18:45:11Z
dc.date.available2018-04-18T18:45:11Z
dc.date.issued1981-07
dc.identifier.urihttps://hdl.handle.net/1912/10269
dc.descriptionAlso published as: Journal of the Acoustical Society of America 69 (1981): 84-94en_US
dc.description.abstractThe results of a deep-ocean bottom interaction experiment are presented in which the effects of both bottom refraction and subbottom reflection were observed. Data were obtained in the Hatteras Abyssal Plain using a deep towed 220-Hz pulsed cw source and two receivers anchored near the bottom. For ranges between 1 and 6 km, corresponding to bottom grazing angles less than 13°, the quadrature components of the received signals were recorded digitally. The observed amplitude shows a strong spatial interference pattern which is composed of the direct and bottom interacting arrivals. It is shown that for small source-receiver separations, the bottom return is dominated by a strong subbollom reflection. With increasing separation, this arrival evolves into a refracted arrival due to the presence of a positive sound-speed gradient in the sediment overlying the subbottom. Because of the gradient, a caustic is formed, and corresponding high intensity regions are observed in the data at the expected ranges. Values of sediment layer thickness, sound-speed gradient, and sound-speed drop at the water-bollom interface are obtained from best fits to the data using ray theory, normal mode theory, and the parabolic equation method. These values are consistent with those obtained in nearby locations by other workers. The success of the parabolic equation method indicates that at small grazing angles, the bottom interaction process may be modeled as a propagation process combined with the effect of a perfect, soft subbollom reflector. A value of sediment attenuation, 0.0015 dB/mat 220Hz, is also inferred from the data and is among the lowest values reported to date in the literature.en_US
dc.description.sponsorshipPrepared for the Office of Naval Research under Contract N00014-77-C-0196 administered through NORDAen_US
dc.language.isoen_USen_US
dc.publisherWoods Hole Oceanographic Institutionen_US
dc.relation.ispartofseriesWHOI Technical Reportsen_US
dc.relation.ispartofseriesWHOI-81-64en_US
dc.subjectMarine sedimentsen_US
dc.subjectAcoustical engineeringen_US
dc.titleBottom interaction of low-frequency acoustic signals at small grazing angles in the deep oceanen_US
dc.typeTechnical Reporten_US
dc.identifier.doi10.1575/1912/10269


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