Virgil Kauffman Gold Medal for George 
A. McMechan, by Oz Yilmaz

The Society of Exploration Geophysicists hornors George McMechan, the Ida Green Professor of Geophysics at the University of Texas-Dallas, with the Virgil Kauffman Gold Medal for the broad scope of his sustained work in seismic wave field modeling and migration during the past ten years.

      George and his students have developed 2-D and 3-D wave field modeling and migration algorithms applicable to exploration targets associated with steep salt flanks and below complex overburden structures associated with overthrust and salt tectonics. Among the broad category of algorithms George has developed, those for acoustic reverse time migration with extensions to elastic, prestack and 3-D data, and multiparameter modeling and inversion stand out distinctively. George has combined his broad and deep theoretical knowledge of the wave field theory with his practical insight for efficient design of algorithms implemented in various domains -- space-time, space-frequency, and ray parameter. To make them usable in the industry, many of these algorithms were specifically developed for multiprocessor servers. While many researchers have done substantial work in wave field modeling and imaging, the research results by George are directly applicable to structural plays of interest in exploring oil and gas fields.

      George received a B.S. degree in geological engineering from the University of British Columbia and an M.S. in physics (1971) from the University of Toronto. He began his career in 1972 at a branch of the Canadian Department of Energy, Mines and Resources where he made his first contributions to the delineation of the upper mantle. During 1979-1980, he was a visiting scientist with the Stanford Exploration Project at Stanford University, which is where we first met. His warm and approachable character effortlessly led me to a lifelong friendship. His earlier work in the earth's depths evolved into inversion of reflection and refraction data based on p-tau transformation. It was evident that George would make his mark in seismic research and development.

      After a one-year term at the University of Virginia, George joined the University of Texas-Dallas as an associate professor. In 1983, he published his first paper on acoustic reverse-time migration and his first on seismic tomography. These were followed over the years by papers on extensions to elastic, prestack and 3-D reverse-time migration.

      In 1985 George became full professor and director of the Center for Lithospheric Studies. In 1986 he developed algorithms for analyzing VSP and crosshole seismic data. In 1987 he started the UT-Dallas Geophysical Consortium to produce results directly applicable to exploration and development problems. He foresaw the need for high-performance multiprocessor servers in data modeling and earth modeling applications and in 1991 initiated a second consortlure, the UT-Dallas Parallel Computing Consortium, for developing modeling and imaging algorithms suitable for large-scale 3-D data sets. Since then George has consulted for oil and service companies on projects involving development of 3-D prestack migration software.

      Recent research activities extended George's interests to reservoir characterization by way of modeling and inversion for AVO attributes, including viscoelasticity and scattering as well as elastic parameters. Then in 1994 he began investigating potential use of ground-penetrating radar for 3-D characterization of reservoir analogs in both clastic and carbonate environments. This work led to a third consortium, the UT-Dallas GPR Consortium, in 1991. Aside from seismic and GPR, George has done research in magnetotellurics, electromagnetic imaging, image processing, Biot theory, earthquake source imaging, solid earth modeling, and rock physics. Such broad scope of research over a 25-year career has made George a prolific author of morc than 150 papers, including 51 in GEOPHYSICS.

      George is a member of SEG, AGU, the Seismological Society of America, and the Environmental and Engineering Geophysical Society. He served as an associate editor of GEOPHYSlCS (1985-87, 1995-97), as an editorial board member of the International Journal of Imaging Systems and Technology (1988-94), and as an editorial board member of the Journal of Seismic Exploration (1991-97).

      For all his contributions, especially his extensive work on seismic wave field modeling and migration, we honor George with the Virgil Kauffman Award.