William Maurice "Doc" Ewing was an American geophysicist and oceanographer.
Background
He was born in Lockney, Texas, the fourth of ten children of Floyd Ford Ewing and Hope Hamilton. The eldest three children died very young, in New Mexico, before the family moved to the small town of Lockney. There Ewing's father was a farmer and a dealer in hardware and farm equipment.
Education
Both parents were intent upon their children acquiring a good education.
Ewing attended Rice Institute (now University) in Houston, Texas, on a scholarship after his first year.
There he received a B. A. in physics in 1926, an M. A. in 1927, and a Ph. D. in 1931.
Career
During college summers Ewing worked for oil-prospecting companies, which provided field experience in seismic techniques in shallow lakes in Louisiana. Ewing became instructor in physics at the University of Pittsburgh in 1929, and a year later he took a similar position at Lehigh University, where he was named associate professor in 1940.
There he initiated the use at sea of explosives, called seismic refraction, to determine subsurface structure, a technique well established by then in exploration for oil on land.
In 1935 he completed the first seismic-refraction lines across the continental shelf of the eastern United States and determined the sediment thickness. The next year he measured gravity at the Puerto Rico Trench.
About 1939, with John Lamar Worzel and Allyn C. Vine, Ewing designed a prototype underwater camera; his photos were the first to show ripple marks on the ocean floor in deep water, suggesting previously unsuspected motion at such depths. Gradually, using ships of various agencies, Ewing extended his studies beyond the continental shelf to the deep ocean, modifying equipment and techniques.
On leave from Lehigh in 1940, Ewing, Vine, and Worzel went to Woods Hole Oceanographic Institution in Massachusetts to carry out basic oceanic studies for the U. S. Navy. An early report by Ewing, Worzel, and Columbus Iselin, "Sound Transmission in Sea Water" (1940), became a standard navy reference on the complex factors that affect underwater sound.
Ewing, Worzel, and Vine also improved the bathythermograph, an oceanographic research device invented by Athelstan Spilhaus, so that it could instantly record ocean temperatures at depth from moving ships.
Ewing discovered the low-velocity sound channel in the ocean called SOFAR, in which sound carries for unusually great distances.
Apparently at the instigation of Walter H. Bucher, Ewing established a program in geophysics at Columbia University in 1946.
He was named Higgins Professor of Geology at Columbia in 1947. When the 125-acre estate of Thomas Lamont was given to the university in 1948, Ewing's group, which required a quiet location for instruments, moved to that site, a few miles from the city campus, and the facility was named Lamont Geological Observatory.
A major donation from the Doherty Foundation in 1969 brought about a change in name to Lamont-Doherty Geological Observatory.
Ewing generated all programs at the observatory and participated in most of the publications by its staff from 1948 until 1972. Colleagues and students found him inexhaustible, on land or at sea, and an inspiring teacher through ideas and by example.
He was a good improvisor of techniques to accomplish the task and thoroughly enjoyed research aboard ship.
In 1949 Ewing first used two research vessels for seismic-refraction studies, in order to gain the longer distances necessary for measurements of the thickness of the earth's crust through the ocean and its floor.
At the same time, as another approach to determining subsurface structure, with Frank Press he began a network of seismographs to record the long, slow oscillations from earthquakes.
These programs confirmed the universal difference in crustal thickness between the ocean floor and the continents. Oceanography advanced greatly during the 1950's, especially with support from the Office of Naval Research.
For Lamont, Ewing acquired his first ship in 1953, which made possible worldwide expeditions with multiple programs.
He obtained a second research ship in 1962. Ewing and his colleagues improved the depth recorder for underway use, adapted the airborne magnetometer for its first use towed behind a ship, developed a technique for releasing deep-sea equipment free-fall for return by gasoline-filled balloons, and refined a method of measuring gravity from surface ships.
With Bruce C. Heezen he identified the effects of turbidity currents in deep water, and he participated in the definition of the Mid-Atlantic Ridge as part of a worldwide feature. Researchers and technicians at Lamont constantly developed and improved equipment for deep-sea use. The Lamont geophysical records contributed significantly to the understanding of seafloor spreading as proposed in the mid-1960's that eventually led to understanding the movement of continents.
Ewing was not an early believer in the revolutionary theory, but came to accept it. Ewing participated in the establishment in midcentury of a worldwide deep-ocean drilling program to define the earth's history. Ewing and Worzel led the first voyage on the drilling ship in 1968.
There he was provided with research facilities and a small ship, from which he began studying the subsurface structure of the Gulf of Mexico.
Member of the Foreign Member of the Royal Society (1972)
Member of the American Academy of Arts and Sciences
Member of the American Philosophical Society
Foreign Member of the Geological Society of London, 1964
Connections
In 1928 Ewing married fellow student Avarilla Hildenbrand; they had one son. Ewing was divorced in 1941, and in 1944 he married Margaret Kidder. Ewing and his second wife were divorced in 1965, and he married Harriet Bassett that same year.