Biography Citation for the Reginald Fessenden Award
Contributed by C. G. McBurney
The Society of Exploration Geophysicists honors Leroy C. Paslay with the SEG Medal Award for 1976. This great honor is in recognition of his pioneering accomplishments as the principal developer of the Marine Seismic Streamer now employed exclusively in marine exploration by most governments, oil companies, and geophysical contractors.
Leroy Paslay received a B.S. in Electrical Engineering (with high honors) from Kansas State College in 1930. Then, after two years with General Electric Co., he returned to Kansas State where he received an M.S. in Electrical Engineering and served as Professor of Electrical Engineering for three years. He then entered the geophysical industry in 1936 as director of research with National Geophysical Co. Here, he was a leader in the modernization and improvement of seismic recording instrumentation and exploration techniques until the beginning of World War II, at which time he agreed to serve as Director of the Underwater Sound Division of the Naval Ordnance Laboratories. During this period of service he gained valuable knowledge and wide experience from work in antisubmarine warfare, in the design and operation of antitorpedo devices, and in the design and deployment of sweep-resistant acoustic mines. In recognition of his services, Paslay received the U.S. Navy Distinguished Civilian Service Award.
On termination of hostilities he returned to the geophysical industry resolved to employ his experience and knowledge of underwater sound engineering in the development of an efficient system for the conduct of marine seismic exploration which recently had begun off Texas and Louisiana. His general idea was to develop a system which would require the use of only one ship and would also allow data gathering operations with the ship at a steady cruise. In 1947, he formed Marine Instrument Co., headquartered in Dallas, Texas, to carry out the expansion and development of these ideas.
Paslay had long before determined in his own mind that attainment of his goal called for an entirely new and revolutionary underwater seismic wave detector array, or so-called detector spread. It must be neutrally buoyant so as to be controllable at proper depth; it must be rugged enough to permit detonation of adequate explosive charges below the surface in the space above the array; it must be streamlined or faired to produce the least possible water flow noise; and its sensors must be faithfully sensitive to the seismic pressure wave, but relatively insensitive to velocity of motion in the water.
Following many months of design and testing, the Marine Instrument group had in the water a seismic detector line array which, with the ship at a steady cruise of six knots, fulfilled all of the requirements set out above. Being encased in smooth plastic tubing of relatively uniform diameter and filled with light oil to give it neutral buoyancy, this array streamed out behind the towing head at uniform depth and so was soon termed the Marine Streamer; in the industry, at times the Paslay Streamer. Its performance equaled or exceeded, in every respect, that of any approach anywhere employed therefore; however, in one respect, that of speed and adaptability, the streamer had ushered in a new day. Very shortly the average obtainable miles of seismic profiling per month had increased more than four-fold over the current industry average, and this at greatly reduced cost per month.
Only the marine streamer, with its later refinements focused primarily on reduction of its sensitivity to towing accelerations, makes practical present-day practice of stacked profiling employing low-level energy sources. Thus, Leroy C. Paslay indeed made a fundamental, and still vital, contribution to development of marine seismic data acquisition. His many friends and associates will be pleased by your possibly somewhat overdue recognition.