Acoustic and Mechanical Loading of Marine Sediments

Abstract

Measurements of acoustic and engineering properties of seafloor sediments show that while grain size parameters, along with porosity, dominate in any study of variations of the former, reasonably good prediction equations exist to be able to define the one knowing the other. Thus, while the static elastic moduli are several orders of magnitude less than the equivalent dynamic parameters, it is still possible to make an assessment of their magnitude from acoustic information.

Many of the measured variations can be predicted by the use of normal elastic theory, but such theory cannot account fully for the observed manner in which acoustic energy is lost in marine sediments. While inter-granular friction seems to be the main dissipating mechanism (giving a linear frequency dependence), viscous losses must also exist in any sediment.