Biographical Memoirs Volume 85 (2004) / Chapter Skim
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Louis Byrne Slichter
Louis Byrne Slichter
Pages 268-289
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From page 269... ...
He was a pioneer in studies of inverse problems of geophysics, heat flow and cooling of the earth, free oscillations of the earth, solid-earth tides, crustal seismology, and the application of physical methods to the exploration of mineral deposits. His was the first work in many of these fields.
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From page 270... ...
Mason's solution to improve the signal-to-noise problem was to set up phased, linear arrays of sonic receivers on each side of the bow of a destroyer.1 In the summer of 1917 Lake Mendota, next to the Wisconsin campus, was the site of the first experiments on this project. Later that year Louis and his work on submarine detection moved to the Naval Experiment Station at New London, Connecticut; he was commissioned Ensign Louis Slichter, USNR.
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From page 271... ...
As usual the fieldwork had a theoretical foundation. Slichter's first prospecting paper, in 1928, was a calculation of the susceptibility of dispersed magnetic particles as a function of their concentration, and showed that the great Kursk magnetic anomaly and his own magnetic profiles over the Falconbridge nickel body in Canada could be explained in terms of these susceptibilities.
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From page 272... ...
Most of his theoretical papers from this time forward on inverse problems, heat flow, and free oscillations display elegant skills in applied mathematics. Waldemar Lindgren, chair of the Geology Department at MIT, wanted to start a program of geophysics in his department, and during the Caltech year Louis was invited to join the MIT faculty.
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From page 273... ...
For an application of the inverse conductivity problem, Louis carried out an audacious experiment to measure the electrical conductivity of the earth at depth under Massachusetts. Thirty miles of public utility electric power lines, from Clinton to West Roxbury, were removed from public use and reconnected as a source circuit around midnight when public consumption was low.
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From page 274... ...
Crustal and upper mantle explorations of this type became a hugely popular, widespread activity in Europe and North America in the 1960s and 1970s. Slichter recognized that the problem of temperature distribution in the earth was fundamental to any discussion of the development of the earth and the formation of its surface features.
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From page 275... ...
Both the heat flow and the viscosity studies were important precursors to later work on modeling mantle convection. Well before the start of World War II, Louis' academic life at MIT was interrupted by his involvement once again with issues of national defense; as a member of Division 6 of the National Defense Research Council, he was again concerned with the problems of enemy submarines.
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From page 276... ...
Louis solved the latter problem by an ingenious modification of the air flow around the nose of the model.1 In 1944-1945 a new Institute of Geophysics at the University of California was proposed by members of the faculty at UCLA. Once the proposal was approved, a committee of faculty from both the northern and southern campuses of the University of California, appointed by President Sproul, agreed in October 1945 to locate the headquarters at UCLA, to define the activity of the Institute as research in "the physics of the atmosphere, of the ocean and of the solid earth," and to select Slichter, by then a member of the National Academy of Sciences, having been elected in 1944, as their first choice for director.
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From page 277... ...
In midJuly Slichter accepted an appointment as professor and director of the Institute of Geophysics, effective July 1, 1947.3 The Slichter family arrived in September. With Louis' appointment the model of an Institute at UCLA devoted exclusively to atmospheric science was moot.
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From page 278... ...
(The name had been changed in 1960.) "The Institute of Geophysics and Planetary Physics was Louis' greatest achievement."5 He brought distinguished scientists from a variety of disciplines to UCLA to participate in a continuing colloquy in the interdisciplinary fields of the physical sciences of the natural environment.
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From page 279... ...
A Vening Meinesz and by the models of Griggs, both strong advocates of mantle convection and continental drift, Louis organized expeditions to measure variations of gravity over topographic features of the sea floor by pendulum observations in submarines.
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From page 280... ...
All modes except the purely radial ones had uncertain central frequencies because of the unequal excitation of the multiplets, broadened due to attenuation. These observations of the earth's resonance spectrum formed a basic dataset for inversion to obtain earth structure.
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From page 281... ...
Second, the multiplet splitting of spectral resonances due to the earth's rotation and flattening, would be absent at the Pole, and it might be possible to measure the spectrum with greater accuracy than at lower latitudes. Louis was able to make the first direct observation of the fortnightly solid-earth tide, a considerable achievement because uninterrupted records of deformation over many fortnightly cycles were needed with a stable instrument at the Pole; the work appeared posthumously (1979)
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From page 282... ...
In July 1947, just before coming to UCLA, Louis and his family spent a holiday in Maine, where, of course, he rented a sailboat and entered the races. The rental craft was reputed to have had a very bad racing record over the years, but Louis quickly used his mechanical, fluid mechanics, and strategic skills to overcome its shortcomings.
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From page 283... ...
It is difficult to say whether Louis' own brilliant scientific achievements or his kindly personal influence over those associated with him were of greater significance. His postdoctoral students included leading geophysicists both in the United States and abroad.
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From page 284... ...
Slichter's detailed account of the acoustic submarine detection work of World War I and the torpedo entry work of World War II can be found on pages 212-217 and 227-229, respectively, of W Weaver.
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From page 285... ...
Louis Byrne Slichter: Builder of the Institute of Geophysics and Planetary Physics.
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From page 286... ...
An inverse boundary value problem in electrodynamics. Physics 4:411-418.
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From page 287... ...
Earth tide observations made during the International Geophysical Year.
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From page 288... ...
The residual daily earth tides at South Pole.
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