Unclassified 



Security Classific 



DOCUMENT CONTROL DATA R&D 



Naval Civil Engineering Laboratory 

 Port Hueneme, California 93043 



Unclassified 



OCEAN ENGINEERING SIGNIFICANCE OF MARINE SEISMIC REFLECTION 

 PROFILING TECHNOLOGY 



. DESCRIPTIVE NOTES (Typo of report and inclusive dmtet) 



Final; July 1969-May 1970 



E. F. Pawlowicz 



May 1 971 



NO YF 38.535.001.01.002 



45 



^5_ 



TN-1157 



libera thmt may be sailgned 



Approved for public release; distribution unlimited, 



Naval Facilities Engineering 

 Command 



Seismic Reflection Profiling (SRP) data of value to the seafloor 

 engineer include: (1) sediment ("soil") thickness, (2) sediment struc 

 ture, (3) the slope of the bedrock beneath the sediment layer, (4) 

 bedrock topography, if sufficient tracklines are run to permit con- 

 touring, (5) bedrock structure, if penetration permits, and (6) acous- 

 tical data from which certain physical, engineering, and load bearing 

 properties of an area can be approximated. 



Qualitative interpretations of acoustical data are made as a 

 matter of course by the experienced analyzer of SRP records and 

 include such parameters as: (1) echo intensity from the seafloor and 

 subbottom interfaces, indicating hard (high reflectivity) and soft 

 (low reflectivity) layers, (2) penetrability of the seafloor (in 

 unconsolidated sediments) is generally inversely proportional to 

 grain size, (3) point return, or discrete hyperbolic echo returns, 

 indicative of large irregularities compared to the sound frequency 

 recorded such as boulder beds, or a weathered bedrock surface. 



Quantitative interpretations of seismic reflection data include 

 the measurement of compressional wave velocities by underway wide 



Continued 



DD 



,1473 



Unclassified 



S/N 0101.807-6801 



