J. T. (Ted) Cherry was a pioneer in the development and application of the shear wave vibrator.
Biography Citation for the Virgil Kauffman Gold Medal
Contributed by Carl Kisslinger
The Virgil Kauffman Gold Medal is awarded for an outstanding contribution to the advancement of the science of geophysical exploration as manifested during the previous five years. The wisdom of the authors of this carefully phrased statement is certainly clear in the case of the 1982 Kauffman medalist. J. T. "Ted" Cherry was well out in front of the field when he did his pioneering work on the development and applications of shear-wave VIBROSEIS at Conoco's research laboratories in the early 1960s. During its history to that time, exploration seismology had worked almost exclusively with traveltimes, then amplitudes of compressional waves. Every seismologist knew about shear waves and knew that they carried useful information about the properties of the materials through which they traveled. But the sources in common use, explosive or mechanical, were poor generators of shear waves and seismograms record only with vertical component geophones which were not suitable for detecting shear waves arriving at the surface near normal incidence.
It took a scientist with imagination and foresight to push for a program of research to investigate the potential for exploration applications of shear-wave observations. The climate at Conoco was very favorable for new work at the frontiers of the field. Together with Ken Waters, the co-recipient of the 1982 Kauffman Medal, and the rest of the research group, Ted conceived and designed the field experiments that established the feasibility and value for exploration of shear-wave reflection data. This research was a logical follow-on to Ted's Ph.D. research at St. Louis University, completed in 1961. He had worked on extensions of the theory of wave radiation from force systems applied at the earth's surface.
It often takes time for new technology to be transferred from the research mode in which it is created to operation use. An examination of recent papers in exploration seismology shows the burgeoning impact of the availability of shear-wave data. Physical properties of formations, inaccessible without such data, including Poisson's ratio and anisotropy, are now under active investigation as means for evaluating fundamental characteristics of formations, including fluid content.
Ted Cherry has demonstrated that he is a first rate-theorist who moves easily and enthusiastically into the real world of observations and interpretation of structures and processes in the earth. His work has always been inspired by his perceptions of truly important problems, the solutions to which were needed if geophysics was to make progress. He has given wise direction to the development of the practical tools needed to put his theoretical advances to work. He has shown strong leadership planning, organizing and inspiring quality research by his associates. Ted Cherry is a worthy nominee to join the ranks of the distinguished geophysicists who have received the Kauffman Medal in the past. Ted was my first Ph.D. student, so I take particular pleasure in witnessing this recognition of his achievements and in being given the opportunity to prepare this citation.
Ted moved to Livermore, California in 1963, where he joined the then-called Lawrence Radiation Laboratory as a scientist in the Plowshare Program, devoted to research on peaceful uses of nuclear explosives. His research turned from a primary emphasis on elastic wave propagation to studies of non-linear stress-waves with very large amplitudes. His investigations of cratering phenomena associated with shallow underground explosives led to the development of computer codes yielding accurate predictions of crater dimensions and associated characteristics. You will find the papers based on the work during this period in the rock-mechanics literature, rather than the geophysical journals.
In 1972, he moved from Livermore to LaJolla, California, where he joined Systems, Science, and Software, Inc., as head of the then ascent geophysics group. Now a Senior Vice-President of S3, he has assembled a group of outstanding geophysicists, especially strong in theoretical studies. Their contributions have ranged from the most advanced studies of seismic wave generation by earthquakes and explosions to investigations of methods of exploration for geothermal resources. Their work on the interpretation of combined seismic and gravity data has been productive in shedding light on complicated subsurface structures.