SEG Reginald Fessenden Award 2016 
Sheng Xu and Gilles Lambaré are both being recognized as the researchers who initiated the concept of common-angle migration and who first demonstrated the potential of that approach to seismic imaging. The file of recommendation letters is massive and includes some real SEG heavyweights. These letter writers point out an oversight that must be corrected; i.e., SEG has given two Reginald Fessenden Awards to people who expanded the ideas of Xu and Lambaré, but we have failed to recognize the duo who initiated the idea.
Biography Citation for the SEG Reginald Fessenden Award 2015
Gilles Lambaré is a former student from École Normale Supérieure in Paris, a prestigious teaching and research institute in France. What might appear surprising today is that he started to learn chemistry before discovering geophysics at a research master level. In 1991, he defended a PhD in geophysics from Paris VII on ray-based preserved-amplitude migration under the supervision of Raúl Madariaga and Jean Virieux. That was really the topic he wanted to further investigate.
Gilles spent one year at Politecnico di Milano in Italy with Fabio Rocca and Giuseppe Drufuca. He then became associate professor at MINES ParisTech within the geophysical center led by Pascal Podvin. He participated in European and COPREP projects and the DIG consortium. In 2000, he defended his “habilitation” (HDR) required to supervise PhD students. He joined CGG in 2006 and is currently the research and development director of the subsurface imaging research department in Massy, France. Since 2012, Gilles has been an associate professor at the Institut de Physique du Globe de Paris (IPGP) in France. Gilles has participated since 2004 in the EAGE Technical Program Committee for its annual meeting and is a member of the EAGE Research Committee. He is also an associate editor for Geophysical Prospecting and the Journal of Seismic Exploration.
The award is dedicated to the development of reflection angle domain migration. Together with Sheng Xu, Gilles’ former PhD student and cowinner, they both realized that classical offset migration was suffering from artifacts in complex media. As a solution, they proposed to consider angle gathers. In 2001, their paper was published in Geophysics and is still largely cited today. If this idea appears to be natural today, it was a real change to sort the data according to a physical parameter (angle) instead of acquisition parameter (offset). I think Gilles had the perfect background and way of thinking to come up with such an idea. Here are the reasons:
Angle migration is indeed only one aspect of seismic imaging that Gilles has developed within the high-frequency framework. He is excellent at understanding how rays provide a physical interpretation of the wave propagation. In the 1990s, he developed a wavefront construction tool to compute traveltimes in a given velocity model. With the adaptive mesh refinement, he was able to control the numerical precision. Beyond traveltimes, he fully used the ray framework to compute paraxial quantities and Fréchet derivatives needed for tomography. He came up with stereotomography, a slope tomography approach that takes into account traveltimes and slopes picked in the data. This approach is very attractive as there is no need to pick events on continuous reflectors. Since that time, it was extended to S-tomography and successfully applied on real data sets. Angle migration naturally arose as pairs of rays joining the image point and the source/receiver coordinates explicitly define an angle used in Kirchhoff migration. Gilles also reformulated migration such that it becomes quantitative, with extensions later proposed for the viscoelastic cases. Angle migration today has been extended beyond rays.
Gilles transmitted his passion for geophysics to his former PhD students and among them to Sheng Xu, also honored for the award and with whom he had the opportunity to work again as colleague from 2007 to 2012 at CGGVeritas. To date, he has published more than 30 articles and has coauthored more than 175 conference presentations. He has supervised eight PhD students and five postdocs, and has participated in more than 50 PhD defenses: this is a clear sign that Gilles Lambaré is recognized as an expert in the field of seismic modeling and quantitative imaging, with an intuitive understanding of wave propagation.
- SEG Honors and Awards Ceremony, SEG Dallas 18 October 2016, Omni Dallas Hotel, Dallas Ballroom, International Exposition and Eighty-Sixth Annual Meeting, Dallas, Tx, p, 25.