John W. C. Sherwood A simple axiom "A geophysical success is accurate estimation of the earth model for recorded data" has been the motivating force for John Sherwood's career these last 40 years. How successful have John's contributions been? Today's younger geophysicists would find it difficult to imagine the range of influence that John's work has had on the direction that exploration geophysics has taken. In this regard, the SEG honors John Sherwood with Honorary Membership for his "insights that transposed complicated wave propagation problems into simplified concepts ... (and) being a leading contributor in the field of seismic modeling and imaging. It seems appropriate that John's early work at Imperial College in the mid1950s centered on one of geophysics' more difficult problems, the definition of the near-surface using both physical and theoretical models. After Imperial College, it was two years with the National Research Council of Canada, before John joined forces with the California Research Corporation (Chevron). In the 1960s, at Chevron Research, John developed the analog model for dereverberating the early marine records from the Gulf of Mexico with a spectrum-balancing technique referred to as the CAL Filter. With the computer still in its infancy, John's work on the Seismoline, a tool for both forward and inverse analog modeling of the earth, satisfied Chevron's dream of having "instantaneous" synthetic seismograms. Closely tied to this work were John's contributions to minimum-phase propagation effects and the lucid explanation of the proper sampling technique of the density and velocity logs. Moving from 1-D to 2-D, John still gets a twinkle in his eye when he recalls the results from his digital migration algorithms in the mid-1960s, from the unraveling of the seismic bowties from the San Joaquin Valley to the collapsing of the shallow North Sea fault diffractions. Or, was the twinkle related to his migration patent that ended up in the U.S. Supreme Court? In the early 1970s, John became director of research at Digicon and shortly produced prestack time and depth migrations which led to another significant geophysical contribution, "partial migration before stack," which John named "Devilish," a method we commonly call DMO and MZO. For such a "devilishly" clever idea, the SEG honored John with the Virgil Kauffman Gold Medal in 1986. In 1981, John cofounded Geophysical Development Corporation where he is vice-president of research. During his tenure at GDC, John has continued his efforts to better define the earth model. The SEG again recognized the importance of his work in 1989, when he was asked to be a Distinguished Lecturer. John spoke on the state of the art in seismic depthing and included examples of his robust linearized inversion (RLI) of a depth velocity model from seismic data, a procedure that he recognizes as his major achievement for defining the earth model. In fact, a few years ago, John astonished his colleagues when the RLI technique dramatically demonstrated the field surveying accuracy requirements necessary for seismic depth conversion. The contributions to the SEG and the field of geophysics continue to be an active part of John's life, from reviewing manuscripts, acting as associate editor, speaking at geophysical meetings, to overseeing PhD dissertations. This fervor carries over to John's personal life with stock and business ventures and a museum-quality collection of African art. Step-by-step with John is his dynamic wife, Edith, a biomedical scientist and amateur horticulturist. Of course, the Sherwoods' pride and joy are their three children, who are distinguishing themselves in the fields of medicine and computer science. Few individuals have contributed and distributed as significantly as John has to the SEG. I am proud to summarize a few of John's scientific accomplishments and to be part of this event, as the SEG bestows Honorary Membership on John W. C. Sherwood.

John W.C. Sherwood*, SverreBrandsberg-Dahl, JosteinLima, Following two years in Radar with the UK Royal Air Force, John Sherwood studied Physics at Imperial College, London, this leading to a Ph.D. in Acoustics in 1956. From 1956 - 1958 he was a Post Doc. Fellow at the National Research Council of Canada. Basic studies in Seismology led to employment in 1959 at the California Research Corporation, Chevron, where he was fortunate to be part of the 'Digital Revolution' and remain in it thereafter. From 1969 - 1981 he was with Digicon, becoming V.P. Research while it expanded from 84 employees to around 1500. In 1981 he cofounded Geophysical Development Corporation with Fred Hilterman and RegNeale. Following its sale to Geokineticsin 1998 he became a principal in Applied Geophysical Services, subsequently helping exploit Beam depth migration. Since AGS' acquisition by PGS in 2007, he and son Kevin have remained at PGS and continue to innovate Beam technology. John is privileged to be an Honorary Member of GSH. Due to help from many colleagues he is also fortunate to be the recipient of prestigious awards from SEG, including the Maurice Ewing Medal, the Kauffman Gold Medal, the Cecil Green Enterprise Award and Honorary Membership.

John W. C. Sherwood President of Applied Geophysical Services. Prior to joining AGS, Dr. Sherwood co-founded Geophysical Development Corporation's where he held the position of VP of Research for seventeen years and led development work on prestack migration, DMO, tomography, AVO, FX-Decon, and anisotropy. Dr. Sherwood was also Vice-President of Research at Digicon Geophysical Corporation where he made significant contributions to DISCO, the industry leading seismic computing system. Dr. Sherwood began his career in geophysics as a researcher at California Research Corporation (Chevron) where he was granted the patent for Chevron's first digital migration. He has served as an Associate Editor for Geophysics on several occasions including Associate Editor for Tomography and Seismic Wave Propagation. He is an Honorary Member of the Geophysical Society of Houston and the SEG and received the prestigious Virgil Kauffman Gold Medal Award for his pioneering work in dip moveout and migration. Dr. Sherwood holds a B.Sc. A.R.C.S., D.I.C. and Ph. D. from Imperial College of London and was a Fellow of the National Research Council of Canada.

In 1981, John Sherwood, Reg Neale and he founded Geophysical Development Corporation (GDC) where he was VP of Development.

John W. C. Sherwood A simple axiom-"A geophysical success is accurate estimation of the earth model for recorded data"-has been the motivating force for John Sherwood's career these last 40 years.How successful have John's contributions been?Today's younger geophysicists would find it difficult to imagine the range of influence that John's work has had on the direction that exploration geophysics has taken.In this regard, the SEG honors John Sherwood with Honorary Membership for his "insights that transposed complicated wave propagation problems into simplified concepts ... (and) being a leading contributor in the field of seismic modeling and imaging. It seems appropriate that John's early work at Imperial College in the mid1950s centered on one of geophysics' more difficult problems, the definition of the near-surface using both physical and theoretical models.After Imperial College, it was two years with the National Research Council of Canada, before John joined forces with the California Research Corporation (Chevron). In the 1960s, at Chevron Research, John developed the analog model for dereverberating the early marine records from the Gulf of Mexico with a spectrum-balancing technique referred to as the CAL Filter.With the computer still in its infancy, John's work on the Seismoline, a tool for both forward and inverse analog modeling of the earth, satisfied Chevron's dream of having "instantaneous" synthetic seismograms.Closely tied to this work were John's contributions to minimum-phase propagation effects and the lucid explanation of the proper sampling technique of the density and velocity logs. Moving from 1-D to 2-D, John still gets a twinkle in his eye when he recalls the results from his digital migration algorithms in the mid-1960s, from the unraveling of the seismic bowties from the San Joaquin Valley to the collapsing of the shallow North Sea fault diffractions.Or, was the twinkle related to his migration patent that ended up in the U.S. Supreme Court? In the early 1970s, John became director of research at Digicon and shortly produced prestack time and depth migrations which led to another significant geophysical contribution, "partial migration before stack," which John named "Devilish," a method we commonly call DMO and MZO.For such a "devilishly" clever idea, the SEG honored John with the Virgil Kauffman Gold Medal in 1986. In 1981, John cofounded Geophysical Development Corporation where he is vice-president of research.During his tenure at GDC, John has continued his efforts to better define the earth model.The SEG again recognized the importance of his work in 1989, when he was asked to be a Distinguished Lecturer.John spoke on the state of the art in seismic depthing and included examples of his robust linearized inversion (RLI) of a depth velocity model from seismic data, a procedure that he recognizes as his major achievement for defining the earth model.In fact, a few years ago, John astonished his colleagues when the RLI technique dramatically demonstrated the field surveying accuracy requirements necessary for seismic depth conversion. The contributions to the SEG and the field of geophysics continue to be an active part of John's life, from reviewing manuscripts, acting as associate editor, speaking at geophysical meetings, to overseeing PhD dissertations.This fervor carries over to John's personal life with stock and business ventures and a museum-quality collection of African art.Step-by-step with John is his dynamic wife, Edith, a biomedical scientist and amateur horticulturist.Of course, the Sherwoods' pride and joy are their three children, who are distinguishing themselves in the fields of medicine and computer science. Few individuals have contributed and distributed as significantly as John has to the SEG.I am proud to summarize a few of John's scientific accomplishments and to be part of this event, as the SEG bestows Honorary Membership on John W. C. Sherwood.