Sea floor engineering geomorphology: recent achievements and future directions

New mapping technology is providing perspectives of the sea floor "as if th ere were no ocean", revealing that ocean floors exhibit a wide variety of r elief, sediment properties, and active geologic processes such as erosion, faulting, fluid expulsion, and landslides. The development of coastal and o ffshore resources, such as oil and gas and minerals, involves sea floor eng ineering in remote, complex, and sometimes hazardous environments. Optimum engineering design and construction practice require detailed surveys of se a floor geomorphology, geologic conditions on the sea bed and to various de pths beneath it, combined with geotechnical properties of the sediments and oceanographic information. Integrated site survey models attempt to predic t conditions and process frequencies and magnitudes relevant to the enginee ring design lifetimes of sea floor installations, such as cables, pipelines , production platforms, as well as supporting coastal infrastructure such a s jetties, wharves, bridges and harbors. Recent use of deep water areas for oil and gas production, pipelines, and cable routes are also showing that the "world's greatest slopes", beyond the continental shelves contain excit ing, exotic, and enigmatic geomorphological features and processes. Safe an d cost-effective engineering use of these regions depends upon exciting new technical and conceptual advances for understanding sea floor geomorpholog y - a task which has barely begun. (C) 1999 Elsevier Science B.V. All right s reserved.