Jie Zhang PhD ’97 elected to National Academy of Engineering

Jie Zhang PhD ’97, an alum of MIT Earth Resources Laboratory/EAPS who founded GeoTomo and is now a professor at the University of Science and Technology of China, is one of 87 new members of the US National Academy of Engineering announced this week. Election to the Academy is one of the highest professional honors an engineer can receive. Zhang’s induction is, “for advances in earthquake seismology, geophysical imaging, and medical technology.”

From a biographical sketch of Jie Zhang by colleague Öz Yilmaz:

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.