Skip to Main Content
Book Chapter

LONG-RANGE SOUND TRANSMISSION

By
Maurice Ewing
Maurice Ewing
Search for other works by this author on:
J. Lamar Worzel
J. Lamar Worzel
Search for other works by this author on:
Published:
January 01, 1948

Experiments are described to demonstrate a new method of sonic signalling at extremely long ranges in the oceans, utilizing the natural sound channel. Signals were made by causing a 4-lb. charge of TNT to explode at about 4000-foot depth.

These signals have the following qualities:

(1) Extremely long-range transmission (probably 10,000 miles).

(2) Signal is positively identifiable.

(3) Abrupt termination of the signal allows the arrival time to be read with an accuracy better than 0.05 second. This permits location of the source to within a mile, if the signal is received at three suitably located stations.

(4) The relation of signal duration to distance is such that the distance may be estimated to 30 miles in 1000 from reception at a single station.

The limitations are:

(1) The great-circle path which the sound follows between source and receiver must lie entirely in deep water (probably at least 1000 fathoms).

(2) Sound travels in water at about 1 mile per second, so that the interval between the origin of the signal and its reception becomes sufficiently great to be a handicap for some uses, particularly with aircraft.

The signals were received to distances of 900 miles. In subsequent work, not included in this report, a J-lb. bomb was heard with abundant signal strength at over 800 miles, a 4-lb. bomb at 2300 miles, and a 6-lb. bomb at 3100 miles.

Two receiving arrangements have been used, a hydrophone hung 4000 feet deep over the side of a ship which was hove to, and a shore-connected hydrophone lying on bottom 4000 feet deep. Extrapolation of the results indicated a range of at least 10,000 miles from a 4-lb. charge. Recommendation is made to utilize a network of monitoring stations to locate planes, ships,and life rafts in distress on the open oceans. Three or more stations receiving a signal could locate the source within 1 mile. An experimental network of listening stations is being installed by the Navy Department in the western Pacific, and this system of signalling has been given the name SOFAR.

Three applications of SOFAR to geological problems have been proposed: (1) position fixing, (2) discovery of shoal areas, and (3) submarine volcano location.

You do not currently have access to this article.

Figures & Tables

Contents

GSA Memoirs

Propagation of Sound in the Ocean

J. Lamar Worzel
J. Lamar Worzel
Search for other works by this author on:
Maurice Ewing
Maurice Ewing
Search for other works by this author on:
C. L. Pekeris
C. L. Pekeris
Search for other works by this author on:
Geological Society of America
Volume
27
ISBN print:
9780813710273
Publication date:
January 01, 1948

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal