High-Precision Instrumentation System for Sea-Bed Pressure Measurements in Muddy Sediments

A high-precision system for measuring pressure variations in fine-grained sediments has been developed using quartz oscillating pressure transducers and digital data-handling techniques. This instrument has the important feature of being capable of monitoring remotely both mean and fluctuating components of near-bottom or subbottom sediment density variations and at the same time obtaining a time history of surface water waves and tidal elevation changes. Utilizing this system, we expect to be able to resolve density variations of 0.001 g/cm³ and, with the addition of a porous ceramic stone, to detect pore-water pressure variations of 100 dynes/cm².