The criteria specified for the Virgil Kauffman Gold Medal Award require the recipient to have made an outstanding contribution to the advancement of the science of geophysical exploration during the previous five years. Stuart Crampin's research into shear-wave birefringence, for which the award is being given, goes back much further than this, but it has only been in the past five years that the significance and relevance of his work has been properly recognized by the geophysical community. Much of his studies into wave propagation in anisotropic media, culminating in his recognition of the concept of extensive dilatency anisotropy (EDA), have widespread applications in earthquake seismology and in exploration and production geophysics. Valuable new
     techniques with applications in the mining, hydrocarbon, and geothermal fields may yet result from his work.
     Stuart had a distinguished academic career at the Universities of London and Cambridge, followed by research fellowships at the Institute of Seismology at Uppsala in Sweden and the Seismology Unit at Edinburgh University. Between 1966 and 1969 he was Gassiot Fellow in Seismology at the Natural Environment Research Council in the UK.
     In 1969 Stuart joined the Institute of Geological Sciences, later renamed British Geological Survey (BGS), where he currently holds the position of deputy chief scientific officer. This is a personal appointment allowing him freedom to pursue his own lines of research.
     During his almost two decades with BGS, the earlier years were spent developing theory and computer programs for the propagation of surface and body waves in anisotropic and cracked rocks. Following analysis of data from small earthquakes in Turkey, USSR, Japan, California, and North Wales, Stuart first observed shear-wave splitting in seismic zones and recognized it as the most diagnostic effect of anisotropy on body wave propagation in the earth's crust. This led him to develop the concept of EDA and
     to realize that shear-wave splitting associated with it can be observed whenever suitably recorded data are available, indicating the existence of stress-aligned, fluid-filled cracks throughout most rocks in the upper 10-20 km of the earth's crust. More
     recently his work has followed two parallel lines the effect of the combination of EDA and periodic thin layer (PTL) anisotropy in sedimentary rocks, and the temporal changes in shear-wave splitting before and after earthquakes. The first of these may have great importance in estimating the crack and stress structure of reservoirs for production engineering purposes; the second may prove to be a major advance in earthquake prediction.
     Stuart has published extensively (more than 80 papers to date) with several more either in preparation or already submitted. In addition, he has found time to be a visiting professor at Hokkaido University in Japan and co-organizer of the IASPEI/UNESCO sponsored international workshops on seismic anisotropy in Russia in '82 and '86; the symposia in Tokyo in '85 and Vancouver in '87; and the AGU Chapman Conference in Berkeley in '88.
     In 1986 Stuart embarked on a campaign to persuade the industry to support a research consortium to investigate the internal structure of reservoirs. It is a measure of the esteem in which he is held that on July 5, 1988 six international oil companies, two service companies and UK Government agencies committed themselves to launch and fund the Edinburgh Anisotropy Project for which Stuart Crampin will be principal investigator. This is initially a three-year program based on the BGS establishment in Edinburgh.
     During his career Stuart has received many honors and awards, including Honorary Fellow and Honorary Professor at Edinburgh University, Fellow of the Royal Society of Edinburgh, and the Conrad Schlumberger Award of the EAEG. It is entirely appropriate that the SEG should award him the Virgil Kauffman Gold Medal for his outstanding contribution to our science; and given his unfailing enthusiasm for all he does, we can expect much more from him in the future.
     Stuart is a delightful person to know, and it is a personal privilege and pleasure to have been asked to contribute to his honor in this way.

      Peter Kennett