Publication Date:
2022-05-26
Description:
A deep operating self-contained high-frequency echo
sounder known as Deep Probe was recently developed at W.H.O.I.
under ERDA and Sea Grant contracts for the purpose of resolving
fine details of bottom and sub-bottom sediment layering in the
deep ocean. In August 1975 this system was mounted on R.V. KNORR
for a coring expedition (KNORR #51) to the Rockall Trough area
east of the United Kingdom under the direction of Dr. Charles
Hollister.
The purpose of this exercise was to determine the correlation
between the high frequency acoustic sounding records and
the stratification of several Giant Piston Cores (GPC) taken
in the same area.
Three of these cores, GPC-13, 17 and 19, have been analyzed
and compared graphically with the acoustic survey of each
core location, using Deep Probe, near-bottom, both as a 12 kHz
echo-sounder, and as a deep receiver for detecting returns
from a 3.5 kHz pinger mounted on the surface vessel. The
acoustic traces for both frequencies were then compared for
detail and depth of penetration with respect to the cores.
Good to excellent correlation with core stratigraphy is
indicated at 12 kHz. Resolution ranged from fair to poor at
3.5 kHz although transmission losses through the core were
lower at this frequency.
The general conclusion is that deep echo-sounding at
12 kHz is an excellent technique for delineation of shallow
bottom and sub-bottom sediments in high detail, and that deep
sounders having characteristics similar to Deep Probe could
therefore prove valuable for detailed surveys of small areas
preliminary to coring, or in deep-towed fish form, for general
seismic profiling of shallow sediments over longer tracts in the
deep ocean.
Description:
Prepared for the Sandia Laboratories under
contract number 07-7923.
Keywords:
Echo sounding
;
Marine sediments
;
Knorr (Ship : 1970-) Cruise KN51
Repository Name:
Woods Hole Open Access Server
Type:
Technical Report
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