Sea floor characterization by multiples’ amplitude in monochannel surveys

Abstract

Abstract Lithological characterization of the seafloor is key information for offshore engineering, especially when it comes to pier and platform design. Drilling and coring can be used for local sampling, but continuous profiles or even areal coverage are far preferable. High-resolution seismic profiles are successfully used when ports are not too busy, but otherwise single-channel systems must be used. We show in this paper that even these simpler systems can be used to estimate parameters such as the acoustic impedance of shallow sediments directly beneath the seafloor. We exploit the amplitude decay of the multiple reflections between the seafloor and the surface, which does not depend on the source energy. If the offset between source and receiver is not too small, we can estimate the shallow P velocity and, via the acoustic impedance, also the rock density.