THE VELOCITY AND RAY PATHS OF SOUND WAVES IN DEEP SEA WATER

Abstract

Basic experiments conducted by the U. S. Coast and Geodetic Survey in 1933 and 1934 to determine the ray paths of sound in sea water are reported. Time‐distance, frequency, and amplitude measurements were obtained both in deep sea and shallow waters off the California coast. The mean velocity from a depth of 30 fathoms to a depth of about 1000 fathoms agreed with predictions within a few meters per second. The data indicate a velocity of 1,580 meters per second in the mud‐floor at the experimental site. A high velocity near the source was indicated and the underwater explosion acted as a multiple source. A maximum of five reflections was observed, and diffraction was a factor in the observance of reflections beyond certain critical distances as a result of ray curvature. Direct paths along the surface were also limited by ray curvature. Direct transmission along a narrow (nearly) constant velocity layer at a depth of 100 fathoms was found, but direct transmission along the 400‐fathom velocity inversion could not be definitely established although it seemed highly probable. The direction of first motion associated with several ray paths showed a gradual change of sign with increasing distance.