Determining the structural stability of sediments requires probing the microscopic world of soil particles to measure such unconventional quantities as the amount of water between sediment particles, or ‘pore pressure,’ and the mierostructure, or fabric, of clay sediments. The National Oceanic and Atmospheric Administration recently completed a 2-year series of measurements of pore pressure in sediments where they lie: in their pressurized underwater environment.
Richard Bennett and other NOAA researchers took measurements in the shallow marine waters in heavily drilled shelf areas south of the Mississippi Delta, using a 19-m weighted cylindrical probe. Deployed from a ship, it digs into the soft sediment floor, sensing pore pressure at three locations along its length. This information is recorded by equipment on a nearby oil platform.