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Comparaison des données de réflectivité issues des sondeurs multifaisceaux, sondeurs de sédiments, et sismique HR3D

Abstract : The aim of this study is to understand the variations of acoustic reflectivity values, obtained with differents geophysical tools (different frequency bandwidth), through the same surface. According to Eckart's model, a plane wave echo reflected from a rough surface is reduced in amplitude compared to the one issued from a smooth surface. The difference in amplitude may be evaluated using the Rayleigh parameter defined as the ratio of the acoustic wavenumber over the roughness surface. A validation of this model is proposed through laboratory experimentation then a new pulse compression processing sequence of subbottom profiler data is proposed. This new approach leads to the evaluation of a set of frequency related reflection coefficient values which allows a seabottom roughness evaluation following Eckart's theory and a thin layer detection. The methodology was applied on a marine geophysical data set, and reflectivity values evaluated through different frequency bandwidths (10² Hz, 103 Hz, 104 Hz) were compared. A new deconvolution approach, mixed to the roughness studding could explain differences between reflectivity maps obtained with different geophysical tools.
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https://tel.archives-ouvertes.fr/tel-00113506
Contributor : Sandie Le Conte <>
Submitted on : Monday, November 13, 2006 - 4:30:17 PM
Last modification on : Thursday, January 14, 2021 - 11:40:32 AM
Long-term archiving on: : Tuesday, April 6, 2010 - 6:40:04 PM

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  • HAL Id : tel-00113506, version 1

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Sandie Le Conte. Comparaison des données de réflectivité issues des sondeurs multifaisceaux, sondeurs de sédiments, et sismique HR3D. Acoustique [physics.class-ph]. Université Rennes 1, 2004. Français. ⟨tel-00113506⟩

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