M. King Hubbert
In 1931, Chief M.M. Leighton had a bold plan to invigorate the research capability of the Illinois State Geological Survey. Scouring the country for talent, he located the man he considered "one of the best trained geophysicists in the country", M. King Hubbert, then a 27-year-old Ph.D. candidate at the University of Chicago and an instructor at Columbia University. Although Chief Leighton was not successful in wooing the young Texan to his permanent staff, Hubbert was sufficiently intrigued to provide a geophysical assessment of a program outlined by Leighton and his staff. Hubbert asserted that electrical methods could be an effective and inexpensive tool to map fluorspar and fluorspar-controlling faults and to locate groundwater aquifers. Despite his admitted lack of experience in electrical methods, Hubbert offered to work summers for the Illinois State Geological Survey, conducting preliminary field tests and establishing a research group.
That first summer, the tests for locating both faults and groundwater supplies were very successful. The fluorspar study became a full-blown project, and Hubbert returned in 1932, 1934, and 1935 to complete the fieldwork in Illinois with J. Marvin Weller and in Kentucky with the U.S. Geological Survey. Meanwhile, Leighton, L.E. Workman, and later, Merlyn Buhle, followed up Hubbert's successful groundwater tests with a series of additional electrical investigations. They employed the Wenner method of investigation demonstrated by Hubbert. This method uses simple instrumentation and a symmetric, four-electrode array that is easy to explain to untrained helpers. In 1937, the researchers reported that, "although not infallible, it has been of great value to cities and villages that have heretofore found it difficult to obtain sufficient groundwater supplies." Electrical studies were established as an integral component to the groundwater service function of the Illinois State Geological Survey.
Hubbert leveraged his newfound expertise in electrical methods to provide key insight into the theory of groundwater flow. Using the mathematical analogy that exists between the flow of electricity and the flow of water in porous media as a starting point, Hubbert wrote the definitive Theory of Ground Water Motion in 1940.
Later, Hubbert would become internationally renowned for his keen insights and assessments. Most famous was his 1956 prediction that American oil production would peak in 1966 and then fall off as reserves dwindled. Although he underestimated the reserves, the concept was essentially validated during the oil shortages of the 1970s.
Hubbert went on to publish over 70 articles and several books and was highly honored for his scientific and societal contributions when he died in 1989 at the age of 86.