Abstract

Shallow, high-resolution multichannel 2-D seismic data, with acquisition parameters designed to image core- and outcrop-scale stratigraphic features, were collected across the outer shelf and upper slope, offshore Louisiana. Errors during seismic acquisition led to complications in data processing; however, the quality of the processed data was still excellent. Frequencies up to 1000-1200 Hz were recovered from the subsurface to approximately 150-250 ms (112.5-187.5 m) below the sea-floor, permitting resolution of beds as thin as 0.4 m. Frequencies of 400 Hz or greater are needed to resolve the detailed internal geometry of the middle to upper Pleistocene shelf-edge deltas targeted by this study, where the average spacing between the major deltaic clinoform reflections is approximately 2 ms (1.5 m). The deltaic clinoforms dip at angles up to 8 degrees, and may be spatially aliased at frequencies above 854 Hz at the 3.125 m CDP spacing of this survey. A CDP spacing of 2.2 m or less would be required in order to avoid spatial aliasing of the 1200 Hz events at a dip angle of 8 degrees.

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