Abstract
While the effects of sound pressures in water have been studied extensively, very much less work has been done on seabed vibrations. Our previous work used finite element modeling to interpret the results of field trials, studying propagation through graded seabeds as excited by impulsive energy applied to a point. A new simulation has successfully replicated further features of the original observations, and more field work has addressed other questions. We have concentrated on the water-particle motion near the seabed, as this is well known to be critical for benthic species. The evanescent pressure sound fields set up as the impulsive vibration energy passes are expected to be important for the local species, such as crabs and flatfish. By comparison with effects occurring away from boundaries, these seismic interface waves create vigorous water-particle motion but proportionately less sound pressure. This comparative increase ratio exceeds 12 for unconsolidated sediment areas, as typically used for piling operations.
Highlights
The elastic waves as modeled showed most features of the observed seabed vibrations, so we studied the propagation from the idealized thrust to the consequent motion
The more intense retrograde mode is that which we previously studied, but we intended to further investigate the prograde mode, which cannot exist in the Rayleigh half-space model, but propagates stably in the graded half-space. Both hodographs are prograde, but with contrasting shapes. These examples show how the graded model dispersed energy between modes, but we found no evidence of dispersion within individual modes
Other checks on the validity of the finite element (FE) process include changing the boundary conditions of the FE model
Summary
The Need for More Research into Seabed Vibration. Sound pressure waves within the marine environment are regularly monitored and regulated to minimize adverse effects on marine life [1,2,3,4,5,6]. Few authors have raised concern over the potential effects of seabed vibration. The topic is more complex for many reasons. There are a large range of seabed types. Many measurements have been made, and the reviews by E.L. Hamilton [7] have been found useful. This work has concentrated on flat areas of saturated sediments
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
