C. SUBBOTTOM DEPTH RECORDER (SDR) (cont'd) 



16. Evaluation and recommendations: 



a„ Equipment has been used by Lamont Geological Observatory 

 and Alpine Geophysical Associates for routine surveys. 



b. Equipment is capable of either high resolution or relatively 



deep penetration with the selection of suitable frequencies. 



c. The speed of sound in sediments can be measured by using 



this equipment with a wide separation of the transmitter 

 and receiver. 



d. The SDR is used with a PDR or PGR 



e. The use of a PGR with the SDR is preferable to using a PDR. 



17. References: X-l and X-2 



D. SEISMIC PROFILER 



Patents on the equipment and method used by the Seismic Profiler 

 have been applied for by the Woods Hole Oceanographic Institution 

 (WHOI). 



1. Model: No model number; designed by S. T. Knott 



2. Manufacturer: Woods Hole Oceanographic Institution, Woods Hole, 



Mass. 



3. Approximate cost new: $6,000, not including the PGR 



4. Maximum water depth in which operative: 



Empirically determined: 15,800 feet with all ship noise 

 stopped; 2,400 feet with ship moving at 6 knots (S. T. 

 Knott, written communication) 



Estimated: Not known 



5. Maximum penetration of sediment: 



Empirically determined: 1,200 feet (600 feet of penetration 

 is a more practical value when the instrument is used 

 in water 50 to 60 feet deep: S. T. Knott, written communi- 

 cation) 



Estimated: Not known 



D-6 



