iautyey,. ally Echo sounding profiles across (a) a small canyon and (b) small 
isolated bumps on the relatively flat sea floor of the Blake Plateau. Resolution: 
15 milliseconds per inch. Vertical exaggeration: 30 to l, 
Big. 2, High resolution soundings indicating sediment ponding. In (a) the 
ship's motion on the ocean waves causes oscillations in the echo sequences from 
the bottom, In (b) the effect of two pulse lengths, not greatly different, is compared 
(From Hersey °) 
Fig, 3. High resolution echo soundings of the Nares Abyssal Plain. Indications 
of sediment ponding are interrupted by a small seamount at the right end of record. 
Resolution: Approx. 15 milliseconds per inch. Pulse Length: 0. 2 millisecond. 
Vertical exaggeration: 40 tol. 
Fig. 4. A Block diagram of the Continuous Seismic Profiler. The two- 
channel Precision Graphic Recorder is a part of this system. 
Fig. 9. A seismic reflection profile across the southern tip of Stellwagen 
Bank, Massachusetts Bay. Successive signals maintain their similarity after 
many reflections. (From Hoskins and Knott 19) 
Bie) 6, Seismic reflection records across Georges Bank taken on two, 
synchronized PGR's. The rippled trace on the left is the sea floor and arrows 
indicate seismic reflections from deeply buried acoustic and probable geological 
discontinuities, which are accentuated by this oblique view. Note that these returns 
correlate and background noise generally does not. 
Fig. 7. In an oblique seismic reflection and refraction profile, the travel 
time of the direct arrivals changes as the source and receiver are separated on 
the sea surface. Refracted signals having travelled at greater compressional wave 
velocities than that of water arrive earlier than the directly received water-borne 
arrivals 10, 
Fig. 8. Pinger controlled instrument lowering. The difference in travel time 
between the direct and bottom reflected pings is measured between the traces 
displayed on the PGR record. 
Fig. 9. (a) Scattering layer migration at sunrise. (b) High resolution echoes 
from individual scatterers detected by lowering the sounding transducer among the 
scatterers, 
Fig. 10. Echo ranging on fish schools. One of the fish schools in the record 
to the left is examined with high resolution in the record to the right 2. 
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