Technology Description

Friction-sound is a simple and robust technique for in-situ, screening-level measurement of grain size. Friction-sound is believed to be generated when phonons are produced by the breaking or excitation of atomic or molecular bonds as the probe moves over or through the sediment. Theory and previous empirical studies suggest that friction-sound intensity is linearly related to grain size and probe velocity. A prototype SED-FSP has been constructed and tested in the laboratory. In the prototype SED-FSP, the acoustic pickup was integrated into an existing Trident porewater probe that had been sealed to preclude damage to the microphone. The results confirmed that a Trident-based SED-FSP provides a sensitive measure of grain size and that the amplitude of the sound intensity can clearly delineate between sediments with mean diameters in the clay, silt, and sand size ranges. In the prototype embodiment to be demonstrated in this project, the SED-FSP will be integrated with the Trident Probe for GSI sites and a Sediment Profile Imaging (SPI) system for traditional contaminated sediment sites. The Trident Probe is a screening probe for identifying groundwater discharge zones. Its configuration will provide an effective platform for rapid in-situ screening of both contaminated sediment sites and GSI sites. The SPI system is a profiling camera system that provides a rapid, cost-effective method for optically mapping physical, chemical, and biological characteristics of the surface of the seafloor. The SPI platform provides another ideal deployment strategy to demonstrate the SED-FSP.