During a one-month research cruise to the Gulf of Mexico in deep water (800–2700 m W.D.), over 1,000 meters of sediment samples were obtained with a large-diameter long piston coring system and a large-diameter gravity corer. There is very good agreement between long core shear strength results and conventional boring data at three floating platform sites: Auger, Jolliet, and Marlin. The overall objective of the research project is to understand and predict seabed processes on the continental slope in the northwest Gulf of Mexico, related to the regional geology and engineering properties for the design of seafloor installations.
A new research program on seabed processes in deep water Gulf of Mexico is showing the value of undertaking integrated studies to determine geotechnical and geological properties for geohazard analysis, siting of facilities, and foundation design. A major milestone of the project was the August/September, 1998 research cruise to obtain large-diameter long piston cores of the sediment and perform in situ shear strength and pore pressure measurements. This research is part of a 5-year joint program by the University of Rhode Island (URI) and Texas A&M University (TAMU), which is funded principally by the National Science Foundation with supplemental sponsorship by a consortium of five oil companies and the participation of two consulting firms. The northwestern continental margin of the Gulf of Mexico (Fig. 1) has a very complex bathymetry and morphology, especially on the upper and lower slopes. The primary study area is a 180 km corridor south of Louisiana in water depths ranging from 800 m to 3000 m (Fig. 2). This corridor encompasses a wide range of seabed conditions, including stable plateau regions, slopes with various types of instabilities, basins, faulting, uplifl areas, sediment flows, diapirism, areas with fluid expulsion and gassy zones. Some basins (depressions) show up to 800 m relief, with slope inclinations ranging up to 25°. An example of a subbottom and side-scan record within the primary study corridor is shown in Fig. 3.