The search for sand deposits, referred to initially as the Sand 

 Inventory Program, started in 1964 with a survey off the New Jersey coast 

 (Duane, 1969). Subsequent data collection surveys have included the Inner 

 Continental Shelf areas off New England, Long Island, Delaware, Maryland, 

 Virginia, the Cape Fear area of North Carolina, the east coast of Florida, 

 and southern California. During the past 2 years broader application to 

 the CERC mission of the data collected has been recognized, especially 

 in deciphering the shallow structure of the Continental Shelf, understand- 

 ing shelf sedimentation and hydraulic processes, unraveling geologic his- 

 tory of the shelves, and evaluating the potential for engineering design 

 of manmade structures on the shelf. This more diversified program is 

 now referred to as the Inner Continental Shelf Sediment and Structure 

 (ICONS) Program. 



2. Field and Laboratory Procedures . 



The field exploration phase of the ICONS program uses continuous 

 seismic reflection profiling supplemented by cores of the bottom sediment. 

 Both of these sources of data are obtained by contractual agreement with 

 ocean industry firms. These data are analyzed and interpreted by the CERC 

 Geological Engineering Branch. Support data are obtained from the National 

 Ocean Survey (NOS) (formerly U.S. Coast and Geodetic Survey) hydrographic 

 boat sheets, pertinent professional papers, engineering logs from bore 

 holes, and published literature. 



a. Data Collection Planning . Geophysical survey tracklines are laid 

 out for the study areas in two basic patterns: grid and reconnaissance 

 lines. A grid pattern, with variable line spacing depending on regional 

 geology, is used to cover areas where a more detailed picture of sea floor 

 and subbottom geologic conditions is desirable, usually those areas sus- 

 pected of containing sand and gravel. Reconnaissance lines consist of one 

 or more continuous shore oblique zigzag lines which provide minimal cov- 

 erage for intermediate areas between grids, and a means of correlation of 

 geology between grid areas. Reconnaissance lines provide sufficient infor- 

 mation to reveal the general morphologic and geologic aspects of the area 

 and to identify sea floor areas where more detailed additional data collec- 

 tion may be advisable. 



Selection of individual core sites is based on a continuous study of 

 the seismic records as they become available from the contractor during 

 the survey. This procedure of picking core locations, based on geologic 

 conditions revealed on the seismic records, allows core-site selection on 

 the best information available and thus maximizes usefulness of both 

 sources of data. It also permits the contractor to complete the required 

 work of obtaining geophysics and cores in one area before moving his base 

 of operations to the next area. 



b. Seismic Reflection Profiling . Seismic reflection profiling is a 

 technique widely used for delineating subbottom geologic structures and 

 bedding surfaces in sea floor sediments and rocks. Continuous reflections 

 are obtained by generating repetitive, high-energy, sound pulses near the 

 water surface and recording "echoes" reflected from the sea floor-water 



