Xianhuai Zhu and Jie Zhang are recognized for their outstanding joint contributions to the development of seismic tomographic solutions to the problem of accurate imaging with complex near-surface geology. Their idea and development from the turning ray tomography to full wave front first arrival travel time tomography enabled a more robust imaging approach, with less reliance on the initial model. The vast application areas of this method include many shallow water and land data imaging challenges associated with shallow gas, sand dunes, and structural overthrusts, among others.
Biography Citation for the Reginald Fessenden Award
Contributed by Öz Yilmaz
It is most appropriate for SEG to recognize Jie Zhang with the Reginald Fessenden Award for his pioneering work on nonlinear traveltime tomography. Modeling the near-surface in exploration seismology has been a challenge to us all. The work of Jie Zhang and Xianhuai Zhu have indeed made possible the practical applications of nonlinear tomography and turning-ray tomography, respectively, to estimate near-surface models to correct for the deleterious effect of the complex near-surface more accurately than any other method to date. Moreover, modeling the complex subsurface still poses more challenges. The work of Jie and Xianhuai has inspired many researchers to strive to develop methods for accurate modeling of the subsurface.
Jie received his bachelor’s degree in geophysics (1986) from University of Science and Technology of China (USTC), his master’s in geophysics (1991) from Penn State, and his PhD in geophysics (1996) from MIT. Jie joined the Earth Resources Lab at MIT in 1992 and began to work on methods for near-surface imaging with balanced effort in both fieldwork and theoretical development.
During weekends, he conducted refraction surveys at a dozen of sites in New England. In 1994, Jie took one semester off from MIT and went to Antarctica as a USGS contractor to design and execute 200-km refraction profiles for crustal structure imaging. He was the only representative from US to participate and manage a large international project with partners from three other countries. The Antarctic experience inspired him to develop an algorithm for refraction imaging, and later a career in near-surface imaging. When he developed nonlinear refraction traveltime tomography, he looked into “apparent slowness” and “average slowness” in the traveltime, and fitted not just traveltime, but also physically meaningful shapes of traveltime curves in 2D and traveltime surfaces in 3D.
While applying the method to numerous data sets, Jie continued to improve the refraction imaging technology for better results under the supervision of Nafi Toksöz at MIT. These include nonlinear refraction and reflection traveltime tomography, joint seismic wavefront traveltime tomography and migration, and joint seismic and electrical tomography. These refraction-related imaging methods were presented in 8 of his 20 publications while in graduate school. At the same time, he worked with several other faculty members at MIT and completed and published many projects in earthquake seismology, electrical methods, and environmental and engineering geophysics.
When Jie founded GeoTomo in 1998 in Colorado, he had a clear vision — helping the seismic industry to address the near-surface problems. The GeoTomo team under Jie’s supervision developed integrated near-surface imaging solutions, including conventional delay-time, nonlinear traveltime tomography, early arrival waveform tomography, and joint seismic and gravity inversion.
Not only has the near-surface solution range been extended over the years, but Jie’s refraction imaging method has addressed many significant problems along the way: automatic geometry corrections, large data problems, methods for quality control, iterative picking and imaging process, and refraction interferometric imaging. Today, the near-surface technology developed by Jie’s team at GeoTomo is now being used worldwide for near-surface modeling.
In 2009, Jie began to make plans for his academic career. He taught a graduate course on near-surface geophysics at MIT and Stanford, and inspired several students in their research work. In 2011, Jie returned to China, and founded the Geophysical Research Institute at the University of Science and Technology of China (USTC), his alma mater. He is directly supervising a group of 15 graduate students with research focused on near-surface imaging, particularly on waveform tomography. The SEG Reginald Fessenden Award is a testimony to his scientific accomplishments.